Nanomaterials

14 pages, 5375 KiB

Open AccessArticle

Degradation of Perovskite Thin Films and Solar Cells with Candle Soot C/Ag Electrode Exposed in a Control Ambient

by Mohammad Aminul Islam, Hamidreza Mohafez, Khan Sobayel, Sharifah Fatmadiana Wan Muhamad Hatta, Abul Kalam Mahmud Hasan, Mayeen Uddin Khandaker, Md. Akhtaruzzaman, Ghulam Muhammad and Nowshad Amin

Nanomaterials 2021, 11(12), 3463; https://doi.org/10.3390/nano11123463 - 20 Dec 2021

Cited by 9 | Viewed by 3325

Abstract

Perovskite solar cells (PSCs) have already achieved efficiencies of over 25%; however, their instability and degradation in the operational environment have prevented them from becoming commercially viable. Understanding the degradation mechanism, as well as improving the fabrication technique for achieving high-quality perovskite films, [...] Read more.

Perovskite solar cells (PSCs) have already achieved efficiencies of over 25%; however, their instability and degradation in the operational environment have prevented them from becoming commercially viable. Understanding the degradation mechanism, as well as improving the fabrication technique for achieving high-quality perovskite films, is crucial to overcoming these shortcomings. In this study, we investigated details in the changes of physical properties associated with the degradation and/or decomposition of perovskite films and solar cells using XRD, FESEM, EDX, UV-Vis, Hall-effect, and current-voltage (I-V) measurement techniques. The dissociation, as well as the intensity of perovskite peaks, have been observed as an impact of film degradation by humidity. The decomposition rate of perovskite film has been estimated from the structural and optical changes. The performance degradation of novel planner structure PSCs has been investigated in detail. The PSCs were fabricated in-room ambient using candle soot carbon and screen-printed Ag electrode. It was found that until the perovskite film decomposed by 30%, the film properties and cell efficiency remained stable. Full article

► Show Figures

Figure 1

13 pages, 28561 KiB

Open AccessFeature PaperArticle

Ordered Porous TiO₂@C Layer as an Electrocatalyst Support for Improved Stability in PEMFCs

by Gaoyang Liu, Zhaoyi Yang, Xindong Wang and Baizeng Fang

Nanomaterials 2021, 11(12), 3462; https://doi.org/10.3390/nano11123462 - 20 Dec 2021

Cited by 7 | Viewed by 3284

Abstract

Proton exchange membrane fuel cells (PEMFCs) are the most promising clean energy source in the 21st century. In order to achieve a high power density, electrocatalytic performance, and electrochemical stability, an ordered array structure membrane electrode is highly desired. In this paper, a [...] Read more.

Proton exchange membrane fuel cells (PEMFCs) are the most promising clean energy source in the 21st century. In order to achieve a high power density, electrocatalytic performance, and electrochemical stability, an ordered array structure membrane electrode is highly desired. In this paper, a new porous Pt-TiO₂@C ordered integrated electrode was prepared and applied to the cathode of a PEMFC. The utilization of the TiO₂@C support can significantly decrease the loss of catalyst caused by the oxidation of the carbon from the conventional carbon layer due to the strong interaction of TiO₂ and C. Furthermore, the thin carbon layer coated on TiO₂ provides the rich active sites for the Pt growth, and the ordered support and catalyst structure reduces the mass transport resistance and improves the stability of the electrode. Due to its unique structural characteristics, the ordered porous Pt-TiO₂@C array structure shows an excellent catalytic activity and improved Pt utilization. In addition, the as-developed porous ordered structure exhibits superior stability after 3000 cycles of accelerated durability test, which reveals an electrochemical surface area decay of less than 30%, considerably lower than that (i.e., 80%) observed for the commercial Pt/C. Full article

(This article belongs to the Special Issue Advances in Novel Nanostructured Materials for Electrocatalysis–Trends and Future)

► Show Figures

Figure 1

11 pages, 1945 KiB

Open AccessFeature PaperArticle

Quantitative Evidence for the Dependence of Highly Crystalline Single Wall Carbon Nanotube Synthesis on the Growth Method

by Takashi Tsuji, Guohai Chen, Takahiro Morimoto, Yoshiki Shimizu, Jaeho Kim, Hajime Sakakita, Kenji Hata, Shunsuke Sakurai, Kazufumi Kobashi and Don N. Futaba

Nanomaterials 2021, 11(12), 3461; https://doi.org/10.3390/nano11123461 - 20 Dec 2021

Cited by 5 | Viewed by 3075

Abstract

We present a study quantitatively demonstrating that the method of synthesis (gas phase, fixed bed, non-fixed bed) represents a determining factor in the level of crystallinity in growing single wall carbon nanotubes (SWCNTs). Using far infrared spectroscopy, the “effective length” (associated with the [...] Read more.

We present a study quantitatively demonstrating that the method of synthesis (gas phase, fixed bed, non-fixed bed) represents a determining factor in the level of crystallinity in growing single wall carbon nanotubes (SWCNTs). Using far infrared spectroscopy, the “effective length” (associated with the level of crystallinity) was estimated for CNTs grown using various synthetic methods (lab-produced and supplemented by commercially purchased SWCNTs) as a metric for crystallinity (i.e., defect density). Analysis of the observed “effective lengths” showed that the SWCNTs fell into two general groups: long and short (high and low crystallinity) synthesized by gas-phase methods and all other supported catalyst methods, respectively. Importantly, the “long” group exhibited effective lengths in the range of 700–2200 nm, which was greater than double that of the typical values representing the “short” group (110–490 nm). These results highlight the significant difference in crystallinity. We interpret that the difference in the crystallinity stemmed from stress concentration at the nanotube-catalyst interface during the growth process, which originated from various sources of mismatch in growth rates (e.g., vertically aligned array) as well as impact stress from contact with other substrates during fluidization or rotation. These results are consistent with well-accepted belief, but now are demonstrated quantitatively. Full article

(This article belongs to the Section Synthesis, Interfaces and Nanostructures)

► Show Figures

Figure 1

14 pages, 3966 KiB

Open AccessArticle

A Novel 3D Hierarchical Plasmonic Functional Cu@Co₃O₄@Ag Array as Intelligent SERS Sensing Platform with Trace Droplet Rapid Detection Ability for Pesticide Residue Detection on Fruits and Vegetables

by Guanliang Sun, Ning Li, Dan Wang, Guanchen Xu, Xingshuang Zhang, Hongyu Gong, Dongwei Li, Yong Li, Huaipeng Pang, Meng Gao and Xiu Liang

Nanomaterials 2021, 11(12), 3460; https://doi.org/10.3390/nano11123460 - 20 Dec 2021

Cited by 11 | Viewed by 3632

Abstract

Rapid and effective detection of pesticide residues from complex surfaces of fruits and vegetables has important significance. Herein, we report a novel three-dimensional (3D) hierarchical porous functional surface-enhanced Raman scattering (SERS) substrate, which is fabricated by successive two-step hydrothermal synthesis strategy of silver [...] Read more.

Rapid and effective detection of pesticide residues from complex surfaces of fruits and vegetables has important significance. Herein, we report a novel three-dimensional (3D) hierarchical porous functional surface-enhanced Raman scattering (SERS) substrate, which is fabricated by successive two-step hydrothermal synthesis strategy of silver nanoparticles (Ag NPs) and cobalt oxide nanowires (Co₃O₄ NWs) on the 3D copper foam framework as Cu@Co₃O₄@Ag-H. The strategy offers a new avenue for localized plasmonic materials distribution and construction, which exhibits better morphology regulation ability and SERS activity (or hotspots engineering) than physical spurring obtained Cu@Co₃O₄@Ag-S. The developed Cu@Co₃O₄@Ag-H possesses large surface area and rich hotspots, which contributes to the excellent SERS performance, including homogeneity (RSD of 7.8%), sensitivity (enhancement factor, EF of 2.24 × 10⁸) and stability. The Cu@Co₃O₄@Ag-H not only provides plenty of Electromagnetic enhancement (EM) hotspots but also the trace detection capability for droplet rapid sensing within 2 s. Cu@Co₃O₄@Ag-H substrate is further developed as an effective SERS sensing platform for pesticide residues detection on the surfaces of fruits and vegetables with excellent LOD of 0.1 ppm, which is lower than the most similar reported works. This work offers new potential for bioassay, disease POCT diagnosis, national security, wearable flexible devices, energy storage and other related fields. Full article

(This article belongs to the Special Issue Functional Plasmonic Nanostructures)

► Show Figures

Graphical abstract

19 pages, 5626 KiB

Open AccessFeature PaperArticle

Improvement in Tensile Quasi-Static and Fatigue Properties of Carbon Fiber-Reinforced Epoxy Laminates with Matrices Modified by Carbon Nanotubes and Graphene Nanoplatelets Hybrid Nanofillers

by Yi-Ming Jen and Yu-Ching Huang

Nanomaterials 2021, 11(12), 3459; https://doi.org/10.3390/nano11123459 - 20 Dec 2021

Cited by 9 | Viewed by 3496

Abstract

The monotonic and cyclic properties of carbon fiber-reinforced epoxy (CFEP) laminate specimens with matrices modified by multiwalled carbon nanotubes (MWCNTs) and graphene nanoplatelets (GNPs) were experimentally studied. The laminate specimens were fabricated by the hand lay-up procedure and six MWCNT:GNP weight ratios, i.e., [...] Read more.

The monotonic and cyclic properties of carbon fiber-reinforced epoxy (CFEP) laminate specimens with matrices modified by multiwalled carbon nanotubes (MWCNTs) and graphene nanoplatelets (GNPs) were experimentally studied. The laminate specimens were fabricated by the hand lay-up procedure and six MWCNT:GNP weight ratios, i.e., 0:0, 10:0, 0:10, 5:5, 9:1, and 1:9, were considered to prepare the nanoparticle-modified epoxy resin by using an ultrasonic homogenizer and a planetary centrifugal mixer. Then, these laminate specimens with their matrices modified under various nanofiller ratios were employed to investigate the influence of the number of nanofiller types and hybrid nanofiller ratios on the quasi-static strength, fatigue strength, and mode I fracture toughness. The experimental results show that adding individual types of nanoparticles has a slight influence on the quasi-static and fatigue strengths of the CFEP laminates. However, the remarkable synergistic effect of MWCNTs and GNPs on the studied mechanical properties of the CFEP laminates with matrices reinforced by hybrid nanoparticles has been observed. Examining the evolution of stiffness-based degradation indicates that adding hybrid nanoparticles to the matrix can reduce the degradation effectively. The high experimental data of the mode I fracture toughness of hybrid nano-CFEP laminates demonstrate that embedding hybrid nanoparticles in the matrix is beneficial to the interlaminar properties, further improving the fatigue strength. The pushout mechanism of the MWCNTs and the crack deflection effect of the GNPs suppress the growth and linkage of microcracks in the matrix. Furthermore, the bridging effect of the nanoparticles at the fiber/matrix interface retards the interfacial debonding, further improving the resistance to delamination propagation. Full article

(This article belongs to the Special Issue Fiber Reinforced Polymer Nanocomposites)

► Show Figures

Figure 1

14 pages, 3327 KiB

Open AccessArticle

MicroRNAs as a Suitable Biomarker to Detect the Effects of Long-Term Exposures to Nanomaterials. Studies on TiO₂NP and MWCNT

by Sandra Ballesteros, Gerard Vales, Antonia Velázquez, Susana Pastor, Mohamed Alaraby, Ricard Marcos and Alba Hernández

Nanomaterials 2021, 11(12), 3458; https://doi.org/10.3390/nano11123458 - 20 Dec 2021

Cited by 6 | Viewed by 2650

Abstract

The presence of nanomaterials (NMs) in the environment may represent a serious risk to human health, especially in a scenario of chronic exposure. To evaluate the potential relationship between NM-induced epigenetic alterations and carcinogenesis, the present study analyzed a panel of 33 miRNAs [...] Read more.

The presence of nanomaterials (NMs) in the environment may represent a serious risk to human health, especially in a scenario of chronic exposure. To evaluate the potential relationship between NM-induced epigenetic alterations and carcinogenesis, the present study analyzed a panel of 33 miRNAs related to the cell transformation process in BEAS-2B cells transformed by TiO₂NP and long-term MWCNT exposure. Our battery revealed a large impact on miRNA expression profiling in cells exposed to both NMs. From this analysis, a small set of five miRNAs (miR-23a, miR-25, miR-96, miR-210, and miR-502) were identified as informative biomarkers of the transforming effects induced by NM exposures. The usefulness of this reduced miRNA battery was further validated in other previously generated transformed cell systems by long-term exposure to other NMs (CoNP, ZnONP, MSiNP, and CeO₂NP). Interestingly, the five selected miRNAs were consistently overexpressed in all cell lines and NMs tested. These results confirm the suitability of the proposed set of mRNAs to identify the potential transforming ability of NMs. Particular attention should be paid to the epigenome and especially to miRNAs for hazard assessment of NMs, as wells as for the study of the underlying mechanisms of action. Full article

(This article belongs to the Special Issue Advances in Nano-Bio Interactions: Nanosafety and Nanotoxicology)

► Show Figures

Figure 1

9 pages, 6207 KiB

Open AccessArticle

Single-Port Coherent Perfect Loss in a Photonic Crystal Nanobeam Resonator

by Jihoon Choi and Heeso Noh

Nanomaterials 2021, 11(12), 3457; https://doi.org/10.3390/nano11123457 - 20 Dec 2021

Cited by 1 | Viewed by 2561

Abstract

We numerically demonstrated single-port coherent perfect loss (CPL) with a Fabry–Perot resonator in a photonic crystal (PC) nanobeam by using a perfect magnetic conductor (PMC)-like boundary. The CPL mode with even symmetry can be reduced to a single-port CPL when a PMC boundary [...] Read more.

We numerically demonstrated single-port coherent perfect loss (CPL) with a Fabry–Perot resonator in a photonic crystal (PC) nanobeam by using a perfect magnetic conductor (PMC)-like boundary. The CPL mode with even symmetry can be reduced to a single-port CPL when a PMC boundary is applied. The boundary which acts like a PMC boundary, here known as a PMC-like boundary, and can be realized by adjusting the phase shift of the reflection from the PC when the wavelength of the light is within the photonic bandgap wavelength range. We designed and optimized simple Fabry–Perot resonator and coupler in nanobeam to get the PMC-like boundary. To satisfy the loss condition in CPL, we controlled the coupling loss in the resonator by modifying the lattice constant of the PC used for coupling. By optimizing the coupling loss, we achieved zero reflection (CPL) in a single port with a PMC-like boundary. Full article

► Show Figures

Figure 1

16 pages, 5683 KiB

Open AccessArticle

Three-Layer PdO/CuWO₄/CuO System for Hydrogen Gas Sensing with Reduced Humidity Interference

by Nirmal Kumar, Stanislav Haviar and Petr Zeman

Nanomaterials 2021, 11(12), 3456; https://doi.org/10.3390/nano11123456 - 20 Dec 2021

Cited by 9 | Viewed by 2877

Abstract

The growing hydrogen industry is stimulating an ongoing search for new materials not only for hydrogen production or storage but also for hydrogen sensing. These materials have to be sensitive to hydrogen, but additionally, their synthesis should be compatible with the microcircuit industry [...] Read more.

The growing hydrogen industry is stimulating an ongoing search for new materials not only for hydrogen production or storage but also for hydrogen sensing. These materials have to be sensitive to hydrogen, but additionally, their synthesis should be compatible with the microcircuit industry to enable seamless integration into various devices. In addition, the interference of air humidity remains an issue for hydrogen sensing materials. We approach these challenges using conventional reactive sputter deposition. Using three consequential processes, we synthesized multilayer structures. A basic two-layer system composed of a base layer of cupric oxide (CuO) overlayered with a nanostructured copper tungstate (CuWO₄) exhibits higher sensitivity than individual materials. This is explained by the formation of microscopic heterojunctions. The addition of a third layer of palladium oxide (PdO) in forms of thin film and particles resulted in a reduction in humidity interference. As a result, a sensing three-layer system working at 150 °C with an equalized response in dry/humid air was developed. Full article

(This article belongs to the Special Issue Nanostructured Materials for Gas Sensor Applications)

► Show Figures

Figure 1

15 pages, 3239 KiB

Open AccessFeature PaperArticle

Sol-Gel Synthesis, Structure, Morphology and Magnetic Properties of Ni_0.6Mn_0.4Fe₂O₄ Nanoparticles Embedded in SiO₂ Matrix

by Thomas Dippong, Erika Andrea Levei, Iosif Grigore Deac, Ioan Petean, Gheorghe Borodi and Oana Cadar

Nanomaterials 2021, 11(12), 3455; https://doi.org/10.3390/nano11123455 - 20 Dec 2021

Cited by 41 | Viewed by 3301

Abstract

The structure, morphology and magnetic properties of (Ni_0.6Mn_0.4Fe₂O₄)_α(SiO₂)_100−α (α = 0–100%) nanocomposites (NCs) produced by sol-gel synthesis were investigated using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), atomic force [...] Read more.

The structure, morphology and magnetic properties of (Ni_0.6Mn_0.4Fe₂O₄)_α(SiO₂)_100−α (α = 0–100%) nanocomposites (NCs) produced by sol-gel synthesis were investigated using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), atomic force microscopy (AFM) and vibrating sample magnetometry (VSM). At low calcination temperatures (300 °C), poorly crystallized Ni_0.6Mn_0.4Fe₂O₄, while at high calcination temperatures, well-crystallized Ni_0.6Mn_0.4Fe₂O₄ was obtained along with α-Fe₂O₃, quartz, cristobalite or iron silicate secondary phase, depending on the Ni_0.6Mn_0.4Fe₂O₄ content in the NCs. The average crystallite size increases from 2.6 to 74.5 nm with the increase of calcination temperature and ferrite content embedded in the SiO₂ matrix. The saturation magnetization (Ms) enhances from 2.5 to 80.5 emu/g, the remanent magnetization (M_R) from 0.68 to 12.6 emu/g and the coercive field (H_C) from 126 to 260 Oe with increasing of Ni_0.6Mn_0.4Fe₂O₄ content in the NCs. The SiO₂ matrix has a diamagnetic behavior with a minor ferromagnetic fraction, Ni_0.6Mn_0.4Fe₂O₄ embedded in SiO₂ matrix displays superparamagnetic behavior, while unembedded Ni_0.6Mn_0.4Fe₂O₄ has a high-quality ferromagnetic behavior. Full article

(This article belongs to the Special Issue Characterization and Applications of Metal Ferrite Nanocomposites)

► Show Figures

Figure 1

10 pages, 3208 KiB

Open AccessArticle

Coaxial Electrospinning Construction Si@C Core–Shell Nanofibers for Advanced Flexible Lithium-Ion Batteries

by Li Zeng, Hongxue Xi, Xingang Liu and Chuhong Zhang

Nanomaterials 2021, 11(12), 3454; https://doi.org/10.3390/nano11123454 - 20 Dec 2021

Cited by 16 | Viewed by 3874

Abstract

Silicon (Si) is expected to be a high-energy anode for the next generation of lithium-ion batteries (LIBs). However, the large volume change along with the severe capacity degradation during the cycling process is still a barrier for its practical application. Herein, we successfully [...] Read more.

Silicon (Si) is expected to be a high-energy anode for the next generation of lithium-ion batteries (LIBs). However, the large volume change along with the severe capacity degradation during the cycling process is still a barrier for its practical application. Herein, we successfully construct flexible silicon/carbon nanofibers with a core–shell structure via a facile coaxial electrospinning technique. The resultant Si@C nanofibers (Si@C NFs) are composed of a hard carbon shell and the Si-embedded amorphous carbon core framework demonstrates an initial reversible capacity of 1162.8 mAh g⁻¹ at 0.1 A g⁻¹ with a retained capacity of 762.0 mAh g⁻¹ after 100 cycles. In addition, flexible LIBs assembled with Si@C NFs were hardly impacted under an extreme bending state, illustrating excellent electrochemical performance. The impressive performances are attributed to the high electric conductivity and structural stability of the porous carbon fibers with a hierarchical porous structure, indicating that the novel Si@C NFs fabricated using this electrospinning technique have great potential for advanced flexible energy storage. Full article

(This article belongs to the Special Issue Carbon Nanomaterials for Electrochemical Energy Storage)

► Show Figures

Figure 1

13 pages, 936 KiB

Open AccessArticle

Behaviour of PMMA Resin Composites Incorporated with Nanoparticles or Fibre following Prolonged Water Storage

by Abdulaziz Alhotan, Julian Yates, Saleh Zidan, Julfikar Haider, Carlos Alberto Jurado and Nikolaos Silikas

Nanomaterials 2021, 11(12), 3453; https://doi.org/10.3390/nano11123453 - 20 Dec 2021

Cited by 2 | Viewed by 3731

Abstract

When PMMA denture base acrylics are exposed to oral environments for prolonged periods, the denture base absorbs water, which has a negative influence on the denture material and the degree to which the denture base will be clinically effective. This study assessed the [...] Read more.

When PMMA denture base acrylics are exposed to oral environments for prolonged periods, the denture base absorbs water, which has a negative influence on the denture material and the degree to which the denture base will be clinically effective. This study assessed the water sorption, desorption, and hygroscopic expansion processes within PMMA denture-base resins reinforced with nanoparticles or fibre in comparison to the non-reinforced PMMA. The surfaces of the fillers were modified using a silane coupling agent (y-MPS) before mixing with PMMA. Group C consisted of specimens of pure PMMA whereas groups Z, T, and E consisted of PMMA specimens reinforced with ZrO₂, TiO₂ nanoparticles, or E-glass fibre, respectively. The reinforced groups were subdivided into four subgroups according to the percentage filler added to the PMMA resin by weight (1.5%, 3.0%, 5.0%, or 7.0%). Five specimens in disc shape (25 ± 1 mm × 2.0 ± 0.2 mm) were tested for each group. To assess water sorption and hygroscopic expansion, specimens from each group were individually immersed in water at 37 ± 1 °C for 180 days. The samples were then desorbed for 28 days at 37 ± 1 °C, to measure solubility. Water sorption and solubility were calculated using an electronic balance in accordance with ISO Standard 20795-1, and hygroscopic expansion was measured using a laser micrometre. Statistical analysis was undertaken at a p ≤ 0.05 significance level using a one-way ANOVA followed by Tukey post-hoc tests. The results demonstrated that the values of sorption (W_sp), mass sorption (M_s%), and % expansion within the tested groups reached equilibrium within 180 days. A noticeable difference was observed in groups Z and E for (W_sp)/(M_s%) compared to the Group C, but this was not significant. However, the difference between Group C and Group T for these measurements was significant. Non-significant differences also existed between each respective reinforced group and the control group in terms of hygroscopic expansion % values. During the 28-day desorption period, there were no differences in the values of solubility (W_sl)/mass desorption (M_d%) between Group C and each of the reinforced tested groups. The findings indicate that the inclusion of ZrO₂ nanoparticles or E-glass fibres does not increase the water solubility/sorption of the PMMA. However, modifying the PMMA with TiO₂ did significantly increase the water sorption level. Full article

(This article belongs to the Special Issue Biocompatible Dental Nanomaterials: State of the Art and Perspectives)

► Show Figures

Figure 1

21 pages, 4015 KiB

Open AccessArticle

Nanostructured Modifications of Titanium Surfaces Improve Vascular Regenerative Properties of Exosomes Derived from Mesenchymal Stem Cells: Preliminary In Vitro Results

by Chiara Gardin, Letizia Ferroni, Yaşar Kemal Erdoğan, Federica Zanotti, Francesco De Francesco, Martina Trentini, Giulia Brunello, Batur Ercan and Barbara Zavan

Nanomaterials 2021, 11(12), 3452; https://doi.org/10.3390/nano11123452 - 20 Dec 2021

Cited by 21 | Viewed by 4785

Abstract

(1) Background: Implantation of metal-based scaffolds is a common procedure for treating several diseases. However, the success of the long-term application is limited by an insufficient endothelialization of the material surface. Nanostructured modifications of metal scaffolds represent a promising approach to faster biomaterial [...] Read more.

(1) Background: Implantation of metal-based scaffolds is a common procedure for treating several diseases. However, the success of the long-term application is limited by an insufficient endothelialization of the material surface. Nanostructured modifications of metal scaffolds represent a promising approach to faster biomaterial osteointegration through increasing of endothelial commitment of the mesenchymal stem cells (MSC). (2) Methods: Three different nanotubular Ti surfaces (TNs manufactured by electrochemical anodization with diameters of 25, 80, or 140 nm) were seeded with human MSCs (hMSCs) and their exosomes were isolated and tested with human umbilical vein endothelial cells (HUVECs) to assess whether TNs can influence the secretory functions of hMSCs and whether these in turn affect endothelial and osteogenic cell activities in vitro. (3) Results: The hMSCs adhered on all TNs and significantly expressed angiogenic-related factors after 7 days of culture when compared to untreated Ti substrates. Nanomodifications of Ti surfaces significantly improved the release of hMSCs exosomes, having dimensions below 100 nm and expressing CD63 and CD81 surface markers. These hMSC-derived exosomes were efficiently internalized by HUVECs, promoting their migration and differentiation. In addition, they selectively released a panel of miRNAs directly or indirectly related to angiogenesis. (4) Conclusions: Preconditioning of hMSCs on TNs induced elevated exosomes secretion that stimulated in vitro endothelial and cell activity, which might improve in vivo angiogenesis, supporting faster scaffold integration. Full article

(This article belongs to the Special Issue Nanostructured Materials for Biomedicine and Bioengineering)

► Show Figures

Figure 1

13 pages, 4627 KiB

Open AccessArticle

The Fingerprints of Resonant Frequency for Atomic Vacancy Defect Identification in Graphene

by Liu Chu, Jiajia Shi and Eduardo Souza de Cursi

Nanomaterials 2021, 11(12), 3451; https://doi.org/10.3390/nano11123451 - 20 Dec 2021

Cited by 4 | Viewed by 2691

Abstract

The identification of atomic vacancy defects in graphene is an important and challenging issue, which involves inhomogeneous spatial randomness and requires high experimental conditions. In this paper, the fingerprints of resonant frequency for atomic vacancy defect identification are provided, based on the database [...] Read more.

The identification of atomic vacancy defects in graphene is an important and challenging issue, which involves inhomogeneous spatial randomness and requires high experimental conditions. In this paper, the fingerprints of resonant frequency for atomic vacancy defect identification are provided, based on the database of massive samples. Every possible atomic vacancy defect in the graphene lattice is considered and computed by the finite element model in sequence. Based on the sample database, the histograms of resonant frequency are provided to compare the probability density distributions and interval ranges. Furthermore, the implicit relationship between the locations of the atomic vacancy defects and the resonant frequencies of graphene is established. The fingerprint patterns are depicted by mapping the locations of atomic vacancy defects to the resonant frequency magnitudes. The geometrical characteristics of computed fingerprints are discussed to explore the feasibility of atomic vacancy defects identification. The work in this paper provides meaningful supplementary information for non-destructive defect detection and identification in nanomaterials. Full article

(This article belongs to the Special Issue Computational Discrete Methods in Nanomaterials)

► Show Figures

Figure 1

10 pages, 2135 KiB

Open AccessArticle

Observation of Cu Spin Fluctuations in High-T_c Cuprate Superconductor Nanoparticles Investigated by Muon Spin Relaxation

by Suci Winarsih, Faisal Budiman, Hirofumi Tanaka, Tadashi Adachi, Akihiro Koda, Yoichi Horibe, Budhy Kurniawan, Isao Watanabe and Risdiana Risdiana

Nanomaterials 2021, 11(12), 3450; https://doi.org/10.3390/nano11123450 - 20 Dec 2021

Cited by 6 | Viewed by 3660

Abstract

The nano-size effects of high-T_c cuprate superconductor La₂_−xSr_xCuO₄ with x = 0.20 are investigated using X-ray diffractometry, Transmission electron microscopy, and muon-spin relaxation (μSR). It is investigated whether an increase in the [...] Read more.

The nano-size effects of high-T_c cuprate superconductor La₂_−xSr_xCuO₄ with x = 0.20 are investigated using X-ray diffractometry, Transmission electron microscopy, and muon-spin relaxation (μSR). It is investigated whether an increase in the bond distance of Cu and O atoms in the conducting layer compared to those of the bulk state might affect its physical and magnetic properties. The μSR measurements revealed the slowing down of Cu spin fluctuations in La₂_−xSr_xCuO₄ nanoparticles, indicating the development of a magnetic correlation at low temperatures. The magnetic correlation strengthens as the particle size reduces. This significantly differs from those observed in the bulk form, which show a superconducting state below T_c. It is indicated that reducing the particle size of La₂_−xSr_xCuO₄ down to nanometer size causes the appearance of magnetism. The magnetism enhances with decreasing particle size. Full article

(This article belongs to the Special Issue Superconductivity in Nanosystems)

► Show Figures

Figure 1

12 pages, 2706 KiB

Open AccessArticle

Ti₃Si_0.75Al_0.25C₂ Nanosheets as Promising Anode Material for Li-Ion Batteries

by Jianguang Xu, Qiang Wang, Boman Li, Wei Yao and Meng He

Nanomaterials 2021, 11(12), 3449; https://doi.org/10.3390/nano11123449 - 20 Dec 2021

Cited by 7 | Viewed by 3197

Abstract

Herein we report that novel two-dimensional (2D) Ti₃Si_0.75Al_0.25C₂ (TSAC) nanosheets, obtained by sonically exfoliating their bulk counterpart in alcohol, performs promising electrochemical activities in a reversible lithiation and delithiation procedure. The as-exfoliated 2D TSAC nanosheets show [...] Read more.

Herein we report that novel two-dimensional (2D) Ti₃Si_0.75Al_0.25C₂ (TSAC) nanosheets, obtained by sonically exfoliating their bulk counterpart in alcohol, performs promising electrochemical activities in a reversible lithiation and delithiation procedure. The as-exfoliated 2D TSAC nanosheets show significantly enhanced lithium-ion uptake capability in comparison with their bulk counterpart, with a high capacity of ≈350 mAh g⁻¹ at 200 mA g⁻¹, high cycling stability and excellent rate performance (150 mAh g⁻¹ after 200 cycles at 8000 mA g⁻¹). The enhanced electrochemical performance of TSAC nanosheets is mainly a result of their fast Li-ion transport, large surface area and small charge transfer resistance. The discovery in this work highlights the uniqueness of a family of 2D layered MAX materials, such as Ti₃GeC₂, Ti₃SnC₂ and Ti₂SC, which will likely be the promising choices as anode materials for lithium-ion batteries (LIBs). Full article

(This article belongs to the Special Issue Nanotechnologies and Nanomaterials: Selected Papers from CCMR)

► Show Figures

Figure 1

26 pages, 14657 KiB

Open AccessArticle

The Effect of Silicon Grade and Electrode Architecture on the Performance of Advanced Anodes for Next Generation Lithium-Ion Cells

by Alexandra Meyer, Fabian Ball and Wilhelm Pfleging

Nanomaterials 2021, 11(12), 3448; https://doi.org/10.3390/nano11123448 - 20 Dec 2021

Cited by 18 | Viewed by 3840

Abstract

To increase the specific capacity of anodes for lithium-ion cells, advanced active materials, such as silicon, can be utilized. Silicon has an order of magnitude higher specific capacity compared to the state-of-the-art anode material graphite; therefore, it is a promising candidate to achieve [...] Read more.

To increase the specific capacity of anodes for lithium-ion cells, advanced active materials, such as silicon, can be utilized. Silicon has an order of magnitude higher specific capacity compared to the state-of-the-art anode material graphite; therefore, it is a promising candidate to achieve this target. In this study, different types of silicon nanopowders were introduced as active material for the manufacturing of composite silicon/graphite electrodes. The materials were selected from different suppliers providing different grades of purity and different grain sizes. The slurry preparation, including binder, additives, and active material, was established using a ball milling device and coating was performed via tape casting on a thin copper current collector foil. Composite electrodes with an areal capacity of approximately 1.70 mAh/cm² were deposited. Reference electrodes without silicon were prepared in the same manner, and they showed slightly lower areal capacities. High repetition rate, ultrafast laser ablation was applied to these high-power electrodes in order to introduce line structures with a periodicity of 200 µm. The electrochemical performance of the anodes was evaluated as rate capability and operational lifetime measurements including pouch cells with NMC 622 as counter electrodes. For the silicon/graphite composite electrodes with the best performance, up to 200 full cycles at a C-rate of 1C were achieved until end of life was reached at 80% relative capacity. Additionally, electrochemical impedance spectroscopies were conducted as a function of state of health to correlate the used silicon grade with solid electrolyte interface (SEI) formation and charge transfer resistance values. Full article

(This article belongs to the Special Issue Functionalized Nanostructures for Novel Energy Storage Systems)

► Show Figures

Figure 1

10 pages, 4381 KiB

Open AccessArticle

Perfect Optical Absorbers by All-Dielectric Photonic Crystal/Metal Heterostructures Due to Optical Tamm State

by Guang Lu, Kaiyuan Zhang, Yunpeng Zhao, Lei Zhang, Ziqian Shang, Haiyang Zhou, Chao Diao and Xiachen Zhou

Nanomaterials 2021, 11(12), 3447; https://doi.org/10.3390/nano11123447 - 20 Dec 2021

Cited by 10 | Viewed by 2955

Abstract

In this study, we theoretically and experimentally investigated the perfect optical absorptance of a photonic heterostructure composed of a truncated all-dielectric photonic crystal (PC) and a thick metal film in the visible regions. The three simulated structures could achieve narrow-band perfect optical absorption [...] Read more.

In this study, we theoretically and experimentally investigated the perfect optical absorptance of a photonic heterostructure composed of a truncated all-dielectric photonic crystal (PC) and a thick metal film in the visible regions. The three simulated structures could achieve narrow-band perfect optical absorption at wavelengths of 500 nm, 600 nm, and 700 nm, respectively. Based on the measured experimental results, the three experimental structures achieved over 90% absorption at wavelengths of 489 nm, 604 nm, and 675 nm, respectively. The experimental results agreed well with the theoretical values. According to electromagnetic field intensity distributions at the absorption wavelengths, the physical mechanism of perfect absorption was derived from the optical Tamm state (OTS). The structure was simple, and the absorption characteristics were not significantly affected by the thickness of the thick metal layer, which creates convenience in the preparation of the structure. In general, the proposed perfect absorbers have exciting prospects in solar energy, optical sensor technology, and other related fields. Full article

(This article belongs to the Section Nanophotonics Materials and Devices)

► Show Figures

Figure 1

13 pages, 628 KiB

Open AccessEditor’s ChoiceReview

Metal and Metal Oxide Nanoparticles in Caries Prevention: A Review

by Mohammed Zahedul Islam Nizami, Veena W. Xu, Iris X. Yin, Ollie Y. Yu and Chun-Hung Chu

Nanomaterials 2021, 11(12), 3446; https://doi.org/10.3390/nano11123446 - 20 Dec 2021

Cited by 44 | Viewed by 5915

Abstract

Nanoparticles based on metal and metallic oxide have become a novel trend for dental use as they interfere with bacterial metabolism and prevent biofilm formation. Metal and metal oxide nanoparticles demonstrate significant antimicrobial activity by metal ion release, oxidative stress induction and non-oxidative [...] Read more.

Nanoparticles based on metal and metallic oxide have become a novel trend for dental use as they interfere with bacterial metabolism and prevent biofilm formation. Metal and metal oxide nanoparticles demonstrate significant antimicrobial activity by metal ion release, oxidative stress induction and non-oxidative mechanisms. Silver, zinc, titanium, copper, and magnesium ions have been used to develop metal and metal oxide nanoparticles. In addition, fluoride has been used to functionalise the metal and metal oxide nanoparticles. The fluoride-functionalised nanoparticles show fluoride-releasing properties that enhance apatite formation, promote remineralisation, and inhibit demineralisation of enamel and dentine. The particles’ nanoscopic size increases their surface-to-volume ratio and bioavailability. The increased surface area facilitates their mechanical bond with tooth tissue. Therefore, metal and metal oxide nanoparticles have been incorporated in dental materials to strengthen the mechanical properties of the materials and to prevent caries development. Another advantage of metal and metal oxide nanoparticles is their easily scalable production. The aim of this study is to provide an overview of the use of metal and metal oxide nanoparticles in caries prevention. The study reviews their effects on dental materials regarding antibacterial, remineralising, aesthetic, and mechanical properties. Full article

(This article belongs to the Special Issue Metallic and Metal Oxide Nanoparticles and Their Applications)

► Show Figures

Figure 1

19 pages, 4982 KiB

Open AccessArticle

Recycling Rusty Iron with Natural Zeolite Heulandite to Create a Unique Nanocatalyst for Green Hydrogen Production

by Mohamed Shaban, Mohammad BinSabt, Ashour M. Ahmed and Fatma Mohamed

Nanomaterials 2021, 11(12), 3445; https://doi.org/10.3390/nano11123445 - 20 Dec 2021

Cited by 8 | Viewed by 3600

Abstract

Corrosion-induced iron rust causes severe danger, pollution, and economic problems. In this work, nanopowders of Fe₂O₃ and Fe₂O₃/zeolite are synthesized for the first time using rusted iron waste and natural zeolite heulandite by chemical precipitation. The [...] Read more.

Corrosion-induced iron rust causes severe danger, pollution, and economic problems. In this work, nanopowders of Fe₂O₃ and Fe₂O₃/zeolite are synthesized for the first time using rusted iron waste and natural zeolite heulandite by chemical precipitation. The chemical composition, nanomorphologies, structural parameters, and optical behaviors are investigated using different techniques. The Fe₂O₃/zeolite nanocomposite showed smaller sizes and greater light absorption capability in visible light than Fe₂O₃ nanopowder. The XRD pattern shows crystalline hematite (α-Fe₂O₃) with a rhombohedral structure. The crystallite sizes for the plane (104) of the Fe₂O₃ and Fe₂O₃/zeolite are 64.84 and 56.53 nm, respectively. The Fe₂O₃ and Fe₂O₃/zeolite have indirect bandgap values of 1.87 and 1.91 eV and direct bandgap values of 2.04 and 2.07 eV, respectively. Fe₂O₃ and Fe₂O₃/zeolite nanophotocatalysts are used for solar photoelectrochemical (PEC) hydrogen production. The Fe₂O₃/zeolite exhibits a PEC catalytic hydrogen production rate of 154.45 mmol/g.h @ 1 V in 0.9 M KOH solution, which is the highest value yet for Fe₂O₃-based photocatalysts. The photocurrent density of Fe₂O₃/zeolite is almost two times that of Fe₂O₃ catalyst, and the IPCE (incident photon-to-current conversion efficiency) reached ~27.34%@307 nm and 1 V. The electrochemical surface area (ECSA) values for Fe₂O₃ and Fe₂O₃/zeolite photocatalysts were 7.414 and 21.236 m²/g, respectively. The rate of hydrogen production for Fe₂O₃/zeolite was 154.44 mmol h⁻¹/g. This nanophotocatalyst has a very low PEC corrosion rate of 7.6 pm/year; it can retain ~97% of its initial performance. Therefore, the present research can be applied industrially as a cost-effective technique to address two issues at once by producing solar hydrogen fuel and recycling the rusted iron wires. Full article

(This article belongs to the Special Issue Nanomaterials for Electrochemical Applications)

► Show Figures

Figure 1

11 pages, 980 KiB

Open AccessEditor’s ChoiceArticle

Crystallization in Zirconia Film Nano-Layered with Silica

by Brecken Larsen, Christopher Ausbeck, Timothy F. Bennet, Gilberto DeSalvo, Riccardo DeSalvo, Tugdual LeBohec, Seth Linker, Marina Mondin and Joshua Neilson

Nanomaterials 2021, 11(12), 3444; https://doi.org/10.3390/nano11123444 - 19 Dec 2021

Cited by 6 | Viewed by 2721

Abstract

Gravitational waves are detected using resonant optical cavity interferometers. The mirror coatings’ inherent thermal noise and photon scattering limit sensitivity. Crystals within the reflective coating may be responsible for either or both noise sources. In this study, we explored crystallization reduction in zirconia [...] Read more.

Gravitational waves are detected using resonant optical cavity interferometers. The mirror coatings’ inherent thermal noise and photon scattering limit sensitivity. Crystals within the reflective coating may be responsible for either or both noise sources. In this study, we explored crystallization reduction in zirconia through nano-layering with silica. We used X-ray diffraction (XRD) to monitor crystal growth between successive annealing cycles. We observed crystal formation at higher temperatures in thinner zirconia layers, indicating that silica is a successful inhibitor of crystal growth. However, the thinnest barriers break down at high temperatures, thus allowing crystal growth beyond each nano-layer. In addition, in samples with thicker zirconia layers, we observe that crystallization saturates with a significant portion of amorphous material remaining. Full article

(This article belongs to the Special Issue Metallic Oxide Nanostructures)

► Show Figures

Figure 1

15 pages, 4348 KiB

Open AccessArticle

Interface Optimization and Transport Modulation of Sm₂O₃/InP Metal Oxide Semiconductor Capacitors with Atomic Layer Deposition-Derived Laminated Interlayer

by Jinyu Lu, Gang He, Jin Yan, Zhenxiang Dai, Ganhong Zheng, Shanshan Jiang, Lesheng Qiao, Qian Gao and Zebo Fang

Nanomaterials 2021, 11(12), 3443; https://doi.org/10.3390/nano11123443 - 19 Dec 2021

Cited by 7 | Viewed by 2572

Abstract

In this paper, the effect of atomic layer deposition-derived laminated interlayer on the interface chemistry and transport characteristics of sputtering-deposited Sm₂O₃/InP gate stacks have been investigated systematically. Based on X-ray photoelectron spectroscopy (XPS) measurements, it can be noted that [...] Read more.

In this paper, the effect of atomic layer deposition-derived laminated interlayer on the interface chemistry and transport characteristics of sputtering-deposited Sm₂O₃/InP gate stacks have been investigated systematically. Based on X-ray photoelectron spectroscopy (XPS) measurements, it can be noted that ALD-derived Al₂O₃ interface passivation layer significantly prevents the appearance of substrate diffusion oxides and substantially optimizes gate dielectric performance. The leakage current experimental results confirm that the Sm₂O₃/Al₂O₃/InP stacked gate dielectric structure exhibits a lower leakage current density than the other samples, reaching a value of 2.87 × 10⁻⁶ A/cm². In addition, conductivity analysis shows that high-quality metal oxide semiconductor capacitors based on Sm₂O₃/Al₂O₃/InP gate stacks have the lowest interfacial density of states (D_it) value of 1.05 × 10¹³ cm⁻² eV⁻¹. The conduction mechanisms of the InP-based MOS capacitors at low temperatures are not yet known, and to further explore the electron transport in InP-based MOS capacitors with different stacked gate dielectric structures, we placed samples for leakage current measurements at low varying temperatures (77–227 K). Based on the measurement results, Sm₂O₃/Al₂O₃/InP stacked gate dielectric is a promising candidate for InP-based metal oxide semiconductor field-effect-transistor devices (MOSFET) in the future. Full article

(This article belongs to the Special Issue Nanoscale Ferroic Materials—Ferroelectric, Piezoelectric, Magnetic, and Multiferroic Materials)

► Show Figures

Figure 1

11 pages, 4808 KiB

Open AccessArticle

Armchair Janus MoSSe Nanoribbon with Spontaneous Curling: A First-Principles Study

by Naizhang Sun, Mingchao Wang, Ruge Quhe, Yumin Liu, Wenjun Liu, Zhenlin Guo and Han Ye

Nanomaterials 2021, 11(12), 3442; https://doi.org/10.3390/nano11123442 - 19 Dec 2021

Cited by 5 | Viewed by 2794

Abstract

Based on density functional theory, we theoretically investigate the electronic structures of free-standing armchair Janus MoSSe nanoribbons (A-MoSSeNR) with width up to 25.5 nm. The equilibrium structures of nanoribbons with spontaneous curling are obtained by energy minimization in molecular dynamics (MD). The curvature [...] Read more.

Based on density functional theory, we theoretically investigate the electronic structures of free-standing armchair Janus MoSSe nanoribbons (A-MoSSeNR) with width up to 25.5 nm. The equilibrium structures of nanoribbons with spontaneous curling are obtained by energy minimization in molecular dynamics (MD). The curvature is 0.178 nm⁻¹ regardless of nanoribbon width. Both finite element method and analytical solution based on continuum theory provide qualitatively consistent results for the curling behavior, reflecting that relaxation of intrinsic strain induced by the atomic asymmetry acts as the driving force. The non-edge bandgap of curled A-MoSSeNR reduces faster with the increase of width compared with planar nanoribbons. It can be observed that the real-space wave function at the non-edge VBM is localized in the central region of the curled nanoribbon. When the curvature is larger than 1.0 nm⁻¹, both edge bandgap and non-edge bandgap shrink with the further increase of curvature. Moreover, we explore the spontaneous curling and consequent sewing process of nanoribbon to form nanotube (Z-MoSSeNT) by MD simulations. The spontaneously formed Z-MoSSeNT with 5.6 nm radius possesses the lowest energy. When radius is smaller than 0.9 nm, the bandgap of Z-MoSSeNT drops rapidly as the radius decreases. We expect the theoretical results can help build the foundation for novel nanoscale devices based on Janus TMD nanoribbons. Full article

(This article belongs to the Section Theory and Simulation of Nanostructures)

► Show Figures

Figure 1

21 pages, 4242 KiB

Open AccessReview

Ink Formulation and Printing Parameters for Inkjet Printing of Two Dimensional Materials: A Mini Review

by Ho-Young Jun, Se-Jung Kim and Chang-Ho Choi

Nanomaterials 2021, 11(12), 3441; https://doi.org/10.3390/nano11123441 - 19 Dec 2021

Cited by 31 | Viewed by 6977

Abstract

Inkjet printing of two-dimensional (2D) material has been a center of interest for wearable electronics and has become a promising platform for next-generation technologies. Despite the enormous progress made in printed 2D materials, there are still challenges in finding the optimal printing conditions [...] Read more.

Inkjet printing of two-dimensional (2D) material has been a center of interest for wearable electronics and has become a promising platform for next-generation technologies. Despite the enormous progress made in printed 2D materials, there are still challenges in finding the optimal printing conditions involving the ink formulation and printing parameters. Adequate ink formulation and printing parameters for target 2D materials rely on empirical studies and repeated trials. Therefore, it is essential to compile promising strategies for ink formulation and printing parameters. In this context, this review discusses the optimal ink formulations to prepare stable ink and steady ink jetting and then explores the critical printing parameters for fabricating printed 2D materials of a high quality. The summary and future prospects for inkjet-printed 2D materials are also addressed. Full article

(This article belongs to the Special Issue Scalable Fabrication of Nanostructured Materials and Devices)

► Show Figures

Figure 1

30 pages, 1839 KiB

Open AccessEditor’s ChoiceReview

Microfluidics Technology for the Design and Formulation of Nanomedicines

by Eman Jaradat, Edward Weaver, Adam Meziane and Dimitrios A. Lamprou

Nanomaterials 2021, 11(12), 3440; https://doi.org/10.3390/nano11123440 - 18 Dec 2021

Cited by 33 | Viewed by 6391

Abstract

In conventional drug administration, drug molecules cross multiple biological barriers, distribute randomly in the tissues, and can release insufficient concentrations at the desired pathological site. Controlling the delivery of the molecules can increase the concentration of the drug in the desired location, leading [...] Read more.

In conventional drug administration, drug molecules cross multiple biological barriers, distribute randomly in the tissues, and can release insufficient concentrations at the desired pathological site. Controlling the delivery of the molecules can increase the concentration of the drug in the desired location, leading to improved efficacy, and reducing the unwanted effects of the molecules under investigation. Nanoparticles (NPs), have shown a distinctive potential in targeting drugs due to their unique properties, such as large surface area and quantum properties. A variety of NPs have been used over the years for the encapsulation of different drugs and biologics, acting as drug carriers, including lipid-based and polymeric NPs. Applying NP platforms in medicines significantly improves the disease diagnosis and therapy. Several conventional methods have been used for the manufacturing of drug loaded NPs, with conventional manufacturing methods having several limitations, leading to multiple drawbacks, including NPs with large particle size and broad size distribution (high polydispersity index), besides the unreproducible formulation and high batch-to-batch variability. Therefore, new methods such as microfluidics (MFs) need to be investigated more thoroughly. MFs, is a novel manufacturing method that uses microchannels to produce a size-controlled and monodispersed NP formulation. In this review, different formulation methods of polymeric and lipid-based NPs will be discussed, emphasizing the different manufacturing methods and their advantages and limitations and how microfluidics has the capacity to overcome these limitations and improve the role of NPs as an effective drug delivery system. Full article

(This article belongs to the Special Issue Nanomaterials for Applied Nanotechnology and Nanoscience)

► Show Figures

Figure 1

26 pages, 5551 KiB

Open AccessArticle

Green Hydrogels Composed of Sodium Mannuronate/Guluronate, Gelatin and Biointeractive Calcium Silicates/Dicalcium Phosphate Dihydrate Designed for Oral Bone Defects Regeneration

by Maria Giovanna Gandolfi, Fausto Zamparini, Sabrina Valente, Greta Parchi, Gianandrea Pasquinelli, Paola Taddei and Carlo Prati

Nanomaterials 2021, 11(12), 3439; https://doi.org/10.3390/nano11123439 - 18 Dec 2021

Cited by 17 | Viewed by 3389

Abstract

Innovative green, eco-friendly, and biologically derived hydrogels for non-load bearing bone sites were conceived and produced. Natural polysaccharides (copolymers of sodium D-mannuronate and L-guluronate) with natural polypeptides (gelatin) and bioactive mineral fillers (calcium silicates CaSi and dicalcium phosphate dihydrate DCPD) were used to [...] Read more.

Innovative green, eco-friendly, and biologically derived hydrogels for non-load bearing bone sites were conceived and produced. Natural polysaccharides (copolymers of sodium D-mannuronate and L-guluronate) with natural polypeptides (gelatin) and bioactive mineral fillers (calcium silicates CaSi and dicalcium phosphate dihydrate DCPD) were used to obtain eco-sustainable biomaterials for oral bone defects. Three PP-x:y formulations were prepared (PP-16:16, PP-33:22, and PP-31:31), where PP represents the polysaccharide/polypeptide matrix and x and y represent the weight % of CaSi and DCPD, respectively. Hydrogels were tested for their chemical-physical properties (calcium release and alkalizing activity in deionized water, porosity, solubility, water sorption, radiopacity), surface microchemistry and micromorphology, apatite nucleation in HBSS by ESEM-EDX, FT-Raman, and micro-Raman spectroscopies. The expression of vascular (CD31) and osteogenic (alkaline phosphatase ALP and osteocalcin OCN) markers by mesenchymal stem cells (MSCs) derived from human vascular walls, cultured in direct contact with hydrogels or with 10% of extracts was analysed. All mineral-filled hydrogels, in particular PP-31:31 and PP-33:22, released Calcium ions and alkalized the soaking water for three days. Calcium ion leakage was high at all the endpoints (3 h–28 d), while pH values were high at 3 h–3 d and then significantly decreased after seven days (p < 0.05). Porosity, solubility, and water sorption were higher for PP-31:31 (p < 0.05). The ESEM of fresh samples showed a compact structure with a few pores containing small mineral granules agglomerated in some areas (size 5–20 microns). PP-CTRL degraded after 1–2 weeks in HBSS. EDX spectroscopy revealed constitutional compounds and elements of the hydrogel (C, O, N, and S) and of the mineral powders (Ca, Si and P). After 28 days in HBSS, the mineral-filled hydrogels revealed a more porous structure, partially covered with a thicker mineral layer on PP-31:31. EDX analyses of the mineral coating showed Ca and P, and Raman revealed the presence of B-type carbonated apatite and calcite. MSCs cultured in contact with mineral-filled hydrogels revealed the expression of genes related to vascular (CD31) and osteogenic (mainly OCN) differentiation. Lower gene expression was found when cells were cultured with extracts added to the culture medium. The incorporation of biointeractive mineral powders in a green bio-derived algae-based matrix allowed to produce bioactive porous hydrogels able to release biologically relevant ions and create a suitable micro-environment for stem cells, resulting in interesting materials for bone regeneration and healing in oral bone defects. Full article

(This article belongs to the Special Issue Nanomaterials for Oral Medicine)

► Show Figures

Figure 1

11 pages, 2873 KiB

Open AccessArticle

Controllable Fabrication of SiC@C-Fe₃O₄ Hybrids and Their Excellent Electromagnetic Absorption Properties

by Liqun Duan, Xiaoqing Dai, Fan Wu, Aming Xie, Jian-An Wu, Minqian Sun and Yilu Xia

Nanomaterials 2021, 11(12), 3438; https://doi.org/10.3390/nano11123438 - 18 Dec 2021

Cited by 3 | Viewed by 2284

Abstract

In this work, a batch of novel ternary hybrids (SiC@C-Fe₃O₄), characterized by SiC nanowires core, carbon shell, and adhered Fe₃O₄ nanoparticles were controllably synthesized via surface carbonization of SiC_nw followed by hydrothermal reaction. Carbon, which [...] Read more.

In this work, a batch of novel ternary hybrids (SiC@C-Fe₃O₄), characterized by SiC nanowires core, carbon shell, and adhered Fe₃O₄ nanoparticles were controllably synthesized via surface carbonization of SiC_nw followed by hydrothermal reaction. Carbon, which was derived from SiC with nanometer thickness, possesses an amorphous structure, while Fe₃O₄ nanoparticles are in a crystalline state. Simultaneously, the inducement of Fe₃O₄ nanoparticles can provide significant magnetic loss, which is well-tuned by changing the molar content of iron precursors (FeCl₃·6H₂O and FeCl₂·4H₂O). SiC@C-Fe₃O₄ hybrids show great electromagnetic absorption performance owing to the synergy effect of dielectric and magnetic losses. The minimum refection loss can reach to −63.71 dB at 11.20 GHz with a thickness of 3.10 mm, while the broad effective absorption bandwidth (EAB) can reach to 7.48 GHz in range of 10.52–18.00 GHz with a thickness of 2.63 mm. Moreover, the EAB can also cover the whole X band and Ku band. The outstanding performance of the obtained material implys that it is a promising candidate as an electromagnetic absorber. Full article

(This article belongs to the Special Issue Rational Design of Carbon-Based Composites and Their Microwave Absorption)

► Show Figures

Figure 1

14 pages, 5348 KiB

Open AccessArticle

Polymer Micro and Nanoparticles Containing B(III) Compounds as Emissive Soft Materials for Cargo Encapsulation and Temperature-Dependent Applications

by Frederico Duarte, Cristián Cuerva, Carlos Fernández-Lodeiro, Javier Fernández-Lodeiro, Raquel Jiménez, Mercedes Cano and Carlos Lodeiro

Nanomaterials 2021, 11(12), 3437; https://doi.org/10.3390/nano11123437 - 18 Dec 2021

Cited by 5 | Viewed by 2988

Abstract

Polymer nanoparticles doped with fluorescent molecules are widely applied for biological assays, local temperature measurements, and other bioimaging applications, overcoming several critical drawbacks, such as dye toxicity, increased water solubility, and allowing imaging of dyes/drug delivery in water. In this work, some polymethylmethacrylate [...] Read more.

Polymer nanoparticles doped with fluorescent molecules are widely applied for biological assays, local temperature measurements, and other bioimaging applications, overcoming several critical drawbacks, such as dye toxicity, increased water solubility, and allowing imaging of dyes/drug delivery in water. In this work, some polymethylmethacrylate (PMMA), polyvinylpyrrolidone (PVP) and poly(styrene-butadiene-styrene) (SBS) based micro and nanoparticles with an average size of about 200 nm and encapsulating B(III) compounds have been prepared via the reprecipitation method by using tetrahydrofuran as the oil phase and water. The compounds are highly hydrophobic, but their encapsulation into a polymer matrix allows obtaining stable colloidal dispersions in water (3.39 µM) that maintain the photophysical behavior of these dyes. Although thermally activated non-radiative processes occur by increasing temperature from 25 to 80 °C, the colloidal suspension of the B(III) particles continues to emit greenish light (λ = 509 nm) at high temperatures. When samples are cooling back to room temperature, the emission is restored, being reversible. A probe of concept drug delivery study was conducted using coumarin 6 as a prototype of a hydrophobic drug. Full article

► Show Figures

Figure 1

12 pages, 1863 KiB

Open AccessArticle

Efficient Achromatic Broadband Focusing and Polarization Manipulation of a Novel Designed Multifunctional Metasurface Zone Plate

by Shaobo Ge, Weiguo Liu, Xueping Sun, Jin Zhang, Pengfei Yang, Yingxue Xi, Shun Zhou, Yechuan Zhu and Xinxin Pu

Nanomaterials 2021, 11(12), 3436; https://doi.org/10.3390/nano11123436 - 18 Dec 2021

Cited by 5 | Viewed by 2727

Abstract

In this paper, comprehensively utilizing the diffraction theory and electromagnetic resonance effect is creatively employed to design a multifunctional metasurface zone plate (MMZP) and achieve the control of polarization states, while maintaining a broadband achromatic converging property in a near-IR region. The MMZP [...] Read more.

In this paper, comprehensively utilizing the diffraction theory and electromagnetic resonance effect is creatively employed to design a multifunctional metasurface zone plate (MMZP) and achieve the control of polarization states, while maintaining a broadband achromatic converging property in a near-IR region. The MMZP consists of several rings with fixed width and varying heights; each ring has a number of nanofins (usually called meta-atoms). The numerical simulation method is used to analyze the intensity distribution and polarization state of the emergent light, and the results show that the designed MMZP can realize the polarization manipulation while keeping the broadband in focus. For a specific design wavelength (0.7 μm), the incident light can be converted from left circularly polarized light to right circularly polarized light after passing through the MMZP, and the focusing efficiency reaches above 35%, which is more than twice as much as reported in the literature. Moreover, the achromatic broadband focusing property of the MMZP is independent with the polarization state of the incident light. This approach broadens degrees of freedom in micro-nano optical design, and is expected to find applications in multifunctional focusing devices and polarization imaging. Full article

(This article belongs to the Special Issue Plasmon Assisted Near-Field Manipulation and Photocatalysis)

► Show Figures

Figure 1

16 pages, 4988 KiB

Open AccessArticle

Solid Oxide Cell Electrode Nanocomposites Fabricated by Inkjet Printing Infiltration of Ceria Scaffolds

by Simone Anelli, Luis Moreno-Sanabria, Federico Baiutti, Marc Torrell and Albert Tarancón

Nanomaterials 2021, 11(12), 3435; https://doi.org/10.3390/nano11123435 - 18 Dec 2021

Cited by 5 | Viewed by 3069

Abstract

The enhancement of solid oxide cell (SOC) oxygen electrode performance through the generation of nanocomposite electrodes via infiltration using wet-chemistry processes has been widely studied in recent years. An efficient oxygen electrode consists of a porous backbone and an active catalyst, which should [...] Read more.

The enhancement of solid oxide cell (SOC) oxygen electrode performance through the generation of nanocomposite electrodes via infiltration using wet-chemistry processes has been widely studied in recent years. An efficient oxygen electrode consists of a porous backbone and an active catalyst, which should provide ionic conductivity, high catalytic activity and electronic conductivity. Inkjet printing is a versatile additive manufacturing technique, which can be used for reliable and homogeneous functionalization of SOC electrodes via infiltration for either small- or large-area devices. In this study, we implemented the utilization of an inkjet printer for the automatic functionalization of different gadolinium-doped ceria scaffolds, via infiltration with ethanol:water-based La_1−xSr_xCo_1−yFe_yO_3−δ (LSCF) ink. Scaffolds based on commercial and mesoporous Gd-doped ceria (CGO) powders were used to demonstrate the versatility of inkjet printing as an infiltration technique. Using yttrium-stabilized zirconia (YSZ) commercial electrolytes, symmetrical LSCF/LSCF–CGO/YSZ/LSCF–CGO/LSCF cells were fabricated via infiltration and characterized by SEM-EDX, XRD and EIS. Microstructural analysis demonstrated the feasibility and reproducibility of the process. Electrochemical characterization lead to an ASR value of ≈1.2 Ω cm² at 750 °C, in the case of nanosized rare earth-doped ceria scaffolds, with the electrode contributing ≈0.18 Ω cm². These results demonstrate the feasibility of inkjet printing as an infiltration technique for SOC fabrication. Full article

(This article belongs to the Special Issue Inkjet Printing of Nanomaterials for Renewable and Sustainable Energy)

► Show Figures

Figure 1

15 pages, 5231 KiB

Open AccessArticle

Mussel-Inspired Fabrication of PDA@PAN Electrospun Nanofibrous Membrane for Oil-in-Water Emulsion Separation

by Haodong Zhao, Yali He, Zhihua Wang, Yanbao Zhao and Lei Sun

Nanomaterials 2021, 11(12), 3434; https://doi.org/10.3390/nano11123434 - 17 Dec 2021

Cited by 15 | Viewed by 3542

Abstract

Emulsified oily wastewater threatens human health seriously, and traditional technologies are unable to separate emulsion containing small sized oil droplets. Currently, oil–water emulsions are usually separated by special wettability membranes, and researchers are devoted to developing membranes with excellent antifouling performance and high [...] Read more.

Emulsified oily wastewater threatens human health seriously, and traditional technologies are unable to separate emulsion containing small sized oil droplets. Currently, oil–water emulsions are usually separated by special wettability membranes, and researchers are devoted to developing membranes with excellent antifouling performance and high permeability. Herein, a novel, simple and low-cost method has been proposed for the separation of emulsion containing surfactants. Polyacrylonitrile (PAN) nanofibers were prepared via electrospinning and then coated by polydopamine (PDA) by using self-polymerization reactions in aqueous solutions. The morphology, structure and oil-in-water emulsion separation properties of the as-prepared PDA@PAN nanofibrous membrane were tested. The results show that PDA@PAN nanofibrous membrane has superhydrophilicity and almost no adhesion to crude oil in water, which exhibits excellent oil–water separation ability. The permeability and separation efficiency of n-hexane/water emulsion are up to 1570 Lm⁻² h⁻¹ bar⁻¹ and 96.1%, respectively. Furthermore, after 10 cycles of separation, the permeability and separation efficiency values do not decrease significantly, indicating its good recycling performance. This research develops a new method for preparing oil–water separation membrane, which can be used for efficient oil-in-water emulsion separation. Full article

► Show Figures

Figure 1

Journal Menu

Journal Browser

Nanomaterials, Volume 11, Issue 12 (December 2021) – 303 articles

Further Information

Guidelines

MDPI Initiatives

Follow MDPI