Nanomaterials

13 pages, 4473 KiB

Open AccessArticle

Development of Thermo-Responsive Polycaprolactone–Polydimethylsiloxane Shrinkable Nanofibre Mesh

by Chia-Hsuan Hsieh, Nur Adila Mohd Razali, Wei-Chih Lin, Zhi-Wei Yu, Dwita Istiqomah, Yohei Kotsuchibashi and Hsing-Hao Su

Nanomaterials 2020, 10(7), 1427; https://doi.org/10.3390/nano10071427 - 21 Jul 2020

Cited by 16 | Viewed by 5043

Abstract

A thermally activated shape memory polymer based on the mixture of polycaprolactone (PCL) and polydimethylsiloxane (PDMS) was fabricated into the nanofibre mesh using the electrospinning process. The added percentages of the PDMS segment in the PCL-based polymer influenced the mechanical properties. Polycaprolactone serves [...] Read more.

A thermally activated shape memory polymer based on the mixture of polycaprolactone (PCL) and polydimethylsiloxane (PDMS) was fabricated into the nanofibre mesh using the electrospinning process. The added percentages of the PDMS segment in the PCL-based polymer influenced the mechanical properties. Polycaprolactone serves as a switching segment to adjust the melting temperature of the shape memory electro-spun PCL–PDMS scaffolds to our body temperature at around 37 °C. Three electro-spun PCL–PDMS copolymer nanofibre samples, including PCL₆–PDMS₄, PCL₇–PDMS₃ and PCL₈–PDMS₂, were characterised to study the thermal and mechanical properties along with the shape memory responses. The results from the experiment showed that the PCL switching segment ratio determines the crystallinity of the copolymer nanofibres, where a higher PCL ratio results in a higher degree of crystallinity. In contrast, the results showed that the mechanical properties of the copolymer samples decreased with the PCL composition ratio. After five thermomechanical cycles, the fabricated copolymer nanofibres exhibited excellent shape memory properties with 98% shape fixity and above 100% recovery ratio. Moreover, biological experiments were applied to evaluate the biocompatibility of the fabricated PCL–PDMS nanofibre mesh. Owing to the thermally activated shape memory performance, the electro-spun PCL–PDMS fibrous mesh has a high potential for biomedical applications such as medical shrinkable tubing and wire. Full article

(This article belongs to the Special Issue Nanofibers and Their Applications in Energy, Biomedical Engineering, Environmental Engineering, and Sensing)

► Show Figures

Figure 1

14 pages, 7260 KiB

Open AccessArticle

Synthesis of In Situ Photoinduced Halloysite-Polypyrrole@Silver Nanocomposite for the Potential Application in Humidity Sensors

by Khouloud Jlassi, Shoaib Mallick, Hafsa Mutahir, Zubair Ahmad and Farid Touati

Nanomaterials 2020, 10(7), 1426; https://doi.org/10.3390/nano10071426 - 21 Jul 2020

Cited by 16 | Viewed by 3085

Abstract

Halloysite-polypyrrole-silver nanocomposite has been prepared via in situ photopolymerizations of pyrrole in the presence of silanized halloysite and silver nitrate as a photoinitiator. The halloysite nanoclay (HNT) was modified using the hydrogen donor silane coupling agent (DMA) in order to provide anchoring sites [...] Read more.

Halloysite-polypyrrole-silver nanocomposite has been prepared via in situ photopolymerizations of pyrrole in the presence of silanized halloysite and silver nitrate as a photoinitiator. The halloysite nanoclay (HNT) was modified using the hydrogen donor silane coupling agent (DMA) in order to provide anchoring sites for the polypyrrole/silver composite (PPy@Ag). The mass loadings for both PPy and Ag have been estimated to be 21 and 26 wt%, respectively. The anchored Ag particles were found in the metallic state. The resulting PPy@Ag-modified silanized HNT has been evaluated for the potential application for impedance humidity sensors. HNT-DMA-PPy@Ag nanocomposite with different weight % of PPy@Ag (0.25 wt%, 0.5 wt%, and 1 wt%) was deposited on the pre-patterned interdigital Indium Tin Oxide (ITO) electrodes by spin coating technique. The addition of Ag nanoparticles within the nanocomposite enhances the hydrophilicity of the sensing film, which improves the sensitivity of the humidity sensors. The HNT-DMA-PPy@Ag (0.5 wt%) nanocomposite-based impedance sensors showed good sensitivity and lowered hysteresis as compared to the other ratios of the composite. The maximum calculated hysteresis loss of the HNT-DMA-PPy@Ag (0.5 wt%)-based humidity sensor is around 4.5% at 80% RH (relative humidity), and the minimum hysteresis loss estimated to be 0.05% at 20% RH levels. The response and recovery time of HNT-DMA-PPy@Ag (0.5 wt%) nanocomposite-based impedance sensors were found to be 30 and 35 s, respectively. The interesting humidity-dependent impedance properties of this novel composite make it promising in humidity sensing. Full article

(This article belongs to the Section Nanoelectronics, Nanosensors and Devices)

► Show Figures

Figure 1

13 pages, 4667 KiB

Open AccessArticle

Non-Linear Optical Properties of Er³⁺–Yb³⁺-Doped NaGdF₄ Nanostructured Glass–Ceramics

by José J. Velázquez, Giulio Gorni, Rolindes Balda, Joaquin Fernández, Laura Pascual, Alicia Durán and Maria J. Pascual

Nanomaterials 2020, 10(7), 1425; https://doi.org/10.3390/nano10071425 - 21 Jul 2020

Cited by 8 | Viewed by 3285

Abstract

Transparent oxyfluoride glass–ceramics containing NaGdF₄ nanocrystals were prepared by melt-quenching and doped with Er³⁺ (0.5 mol%) and different amounts of Yb³⁺ (0–2 mol%). The selected dopant concentration the crystallization thermal treatments were chosen to obtain the most efficient visible up-conversion [...] Read more.

Transparent oxyfluoride glass–ceramics containing NaGdF₄ nanocrystals were prepared by melt-quenching and doped with Er³⁺ (0.5 mol%) and different amounts of Yb³⁺ (0–2 mol%). The selected dopant concentration the crystallization thermal treatments were chosen to obtain the most efficient visible up-conversion emissions, together with near infrared emissions. The crystal size increased with dopant content and treatment time. NaGdF₄ NCs with a size ranging 9–30 nm were obtained after heat treatments at T_g + 20–80 °C as confirmed by X-ray diffraction and high-resolution transmission electron microscopy. Energy dispersive X-ray analysis shows the incorporation of rare earth ions into the NaGdF₄ nanocrystals. Near-infrared emission spectra, together with the up-conversion emissions were measured. The optical characterization of the glass–ceramics clearly shows that Er³⁺ and Yb³⁺ ions are incorporated in the crystalline phase. Moreover, visible up-conversion emissions could be tuned by controlling the nanocrystals size through appropriated heat treatment, making possible a correlation between structural and optical properties. Full article

(This article belongs to the Special Issue Preparation and Application of Nanostructured Glass–Ceramics and Nanocomposites)

► Show Figures

Figure 1

32 pages, 2027 KiB

Open AccessReview

Lipid-Based Drug Delivery Nanoplatforms for Colorectal Cancer Therapy

by Chunhua Yang and Didier Merlin

Nanomaterials 2020, 10(7), 1424; https://doi.org/10.3390/nano10071424 - 21 Jul 2020

Cited by 53 | Viewed by 7172

Abstract

Colorectal cancer (CRC) is a prevalent disease worldwide, and patients at late stages of CRC often suffer from a high mortality rate after surgery. Adjuvant chemotherapeutics (ACs) have been extensively developed to improve the survival rate of such patients, but conventionally formulated ACs [...] Read more.

Colorectal cancer (CRC) is a prevalent disease worldwide, and patients at late stages of CRC often suffer from a high mortality rate after surgery. Adjuvant chemotherapeutics (ACs) have been extensively developed to improve the survival rate of such patients, but conventionally formulated ACs inevitably distribute toxic chemotherapeutic drugs to healthy organs and thus often trigger severe side effects. CRC cells may also develop drug resistance following repeat dosing of conventional ACs, limiting their effectiveness. Given these limitations, researchers have sought to use targeted drug delivery systems (DDSs), specifically the nanotechnology-based DDSs, to deliver the ACs. As lipid-based nanoplatforms have shown the potential to improve the efficacy and safety of various cytotoxic drugs (such as paclitaxel and vincristine) in the clinical treatment of gastric cancer and leukemia, the preclinical progress of lipid-based nanoplatforms has attracted increasing interest. The lipid-based nanoplatforms might be the most promising DDSs to succeed in entering a clinical trial for CRC treatment. This review will briefly examine the history of preclinical research on lipid-based nanoplatforms, summarize the current progress, and discuss the challenges and prospects of using such approaches in the treatment of CRC. Full article

(This article belongs to the Special Issue Nanomaterials: 10th Anniversary)

► Show Figures

Figure 1

10 pages, 3433 KiB

Open AccessArticle

Refractometric Sensitivity Enhancement of Weakly Tilted Fiber Bragg Grating Integrated with Black Phosphorus

by Zhao Zhang, Kun Liu, Junfeng Jiang, Tianhua Xu, Shuang Wang, Jinying Ma, Pengxiang Chang, Jiahang Zhang and Tiegen Liu

Nanomaterials 2020, 10(7), 1423; https://doi.org/10.3390/nano10071423 - 21 Jul 2020

Cited by 8 | Viewed by 2883

Abstract

The sensitivity enhancement of the weakly tilted fiber Bragg grating (WTFBG) integrated with black phosphorus (BP) was investigated via numerical simulations and experimental demonstrations. BP nanosheets were deposited twice on the cylindrical WTFBG surface using the in situ layer-by-layer (i-LbL) deposition technique. The [...] Read more.

The sensitivity enhancement of the weakly tilted fiber Bragg grating (WTFBG) integrated with black phosphorus (BP) was investigated via numerical simulations and experimental demonstrations. BP nanosheets were deposited twice on the cylindrical WTFBG surface using the in situ layer-by-layer (i-LbL) deposition technique. The resonance intensity of the deepest cladding mode located around 1552 nm of WTFBG had a 9.2 dB decrease after the BP deposition process. This allows for the application of the intensity-modulated refractive index (RI) sensor. The sensing platform was implemented on the use of the BP integrated with WTFBG (BP-WTFBG). The refractometric sensing was achieved with the sensitivity enhancement of the resonance intensity modulation of the deepest cladding mode for the BP-WTFBG. The sensitivities were 137.6 dB/RIU and 75.6 dB/RIU in the RI region of 1.33–1.35 and 1.35–1.38, respectively. This platform shows great potential applications for biochemical sensing because of its highly sensitive RI sensing ability around the biochemical sensing window. Full article

► Show Figures

Figure 1

15 pages, 9321 KiB

Open AccessArticle

Atomistic Modelling of Size-Dependent Mechanical Properties and Fracture of Pristine and Defective Cove-Edged Graphene Nanoribbons

by Daniela A. Damasceno, R.K.N.D. Nimal Rajapakse and Euclides Mesquita

Nanomaterials 2020, 10(7), 1422; https://doi.org/10.3390/nano10071422 - 21 Jul 2020

Cited by 13 | Viewed by 3657

Abstract

Cove-edged graphene nanoribbons (CGNR) are a class of nanoribbons with asymmetric edges composed of alternating hexagons and have remarkable electronic properties. Although CGNRs have attractive size-dependent electronic properties their mechanical properties have not been well understood. In practical applications, the mechanical properties such [...] Read more.

Cove-edged graphene nanoribbons (CGNR) are a class of nanoribbons with asymmetric edges composed of alternating hexagons and have remarkable electronic properties. Although CGNRs have attractive size-dependent electronic properties their mechanical properties have not been well understood. In practical applications, the mechanical properties such as tensile strength, ductility and fracture toughness play an important role, especially during device fabrication and operation. This work aims to fill a gap in the understanding of the mechanical behaviour of CGNRs by studying the edge and size effects on the mechanical response by using molecular dynamic simulations. Pristine graphene structures are rarely found in applications. Therefore, this study also examines the effects of topological defects on the mechanical behaviour of CGNR. Ductility and fracture patterns of CGNR with divacancy and topological defects are studied. The results reveal that the CGNR become stronger and slightly more ductile as the width increases in contrast to normal zigzag GNR. Furthermore, the mechanical response of defective CGNRs show complex dependency on the defect configuration and distribution, while the direction of the fracture propagation has a complex dependency on the defect configuration and position. The results also confirm the possibility of topological design of graphene to tailor properties through the manipulation of defect types, orientation, and density and defect networks. Full article

(This article belongs to the Special Issue Advanced Mechanical Modeling of Nanomaterials and Nanostructures)

► Show Figures

Figure 1

21 pages, 19188 KiB

Open AccessReview

Segmented Microfluidic Flow Reactors for Nanomaterial Synthesis

by Yujuan He, Ki-Joong Kim and Chih-hung Chang

Nanomaterials 2020, 10(7), 1421; https://doi.org/10.3390/nano10071421 - 21 Jul 2020

Cited by 26 | Viewed by 4384

Abstract

Microfluidic reactors have remarkably promoted the synthesis and investigation of advanced nanomaterials due to their continuous mode and accelerated heat/mass transfer. Notably, segmented microfluidic flow reactors (SMFRs) are an important class of microfluidic reactors that have been developed to accurately manipulate nanomaterial synthesis [...] Read more.

Microfluidic reactors have remarkably promoted the synthesis and investigation of advanced nanomaterials due to their continuous mode and accelerated heat/mass transfer. Notably, segmented microfluidic flow reactors (SMFRs) are an important class of microfluidic reactors that have been developed to accurately manipulate nanomaterial synthesis by further improvement of the residence time distributions and unique flow behaviors. This review provided a survey of the nanomaterial synthesis in SMFRs for the aspects of fluid dynamics, flow patterns, and mass transfer among and within distinct phases and provided examples of the synthesis of versatile nanomaterials via the use of different flow patterns. Full article

(This article belongs to the Special Issue 10th Anniversary of Nanomaterials—Recent Advances in Synthesis, Interfaces and Nanostructures)

► Show Figures

Figure 1

21 pages, 3726 KiB

Open AccessArticle

Coupling Hydrogenation of Guaiacol with In Situ Hydrogen Production by Glycerol Aqueous Reforming over Ni/Al₂O₃ and Ni-X/Al₂O₃ (X = Cu, Mo, P) Catalysts

by Ziyin Chen, Roman G. Kukushkin, Petr M. Yeletsky, Andrey A. Saraev, Olga A. Bulavchenko and Marcos Millan

Nanomaterials 2020, 10(7), 1420; https://doi.org/10.3390/nano10071420 - 21 Jul 2020

Cited by 15 | Viewed by 3729

Abstract

Biomass-derived liquids, such as bio-oil obtained by fast pyrolysis, can be a valuable source of fuels and chemicals. However, these liquids have high oxygen and water content, needing further upgrading typically involving hydrotreating using H₂ at high pressure and temperature. The harsh [...] Read more.

Biomass-derived liquids, such as bio-oil obtained by fast pyrolysis, can be a valuable source of fuels and chemicals. However, these liquids have high oxygen and water content, needing further upgrading typically involving hydrotreating using H₂ at high pressure and temperature. The harsh reaction conditions and use of expensive H₂ have hindered the progress of this technology and led to the search for alternative processes. In this work, hydrogenation in aqueous phase is investigated using in-situ produced hydrogen from reforming of glycerol, a low-value by-product from biodiesel production, over Ni-based catalysts. Guaiacol was selected as a bio-oil model compound and high conversion (95%) to phenol and aromatic ring hydrogenation products was obtained over Ni/γ-Al₂O₃ at 250 °C and 2-h reaction time. Seventy percent selectivity to cyclohexanol and cyclohexanone was achieved at this condition. Hydrogenation capacity of P and Mo modified Ni/γ-Al₂O₃ was inhibited because more hydrogen undergoes methanation, while Cu showed a good performance in suppressing methane formation. These results demonstrate the feasibility of coupling aqueous phase reforming of glycerol with bio-oil hydrogenation, enabling the reaction to be carried out at lower temperatures and pressures and without the need for molecular H₂. Full article

(This article belongs to the Special Issue Synthesis of Nanocomposites and Catalysis Applications)

► Show Figures

Graphical abstract

15 pages, 2987 KiB

Open AccessArticle

Ti₃C₂T_x MXene-Based Light-Responsive Hydrogel Composite for Bendable Bilayer Photoactuator

by Sifani Zavahir, Patrik Sobolčiak, Igor Krupa, Dong Suk Han, Jan Tkac and Peter Kasak

Nanomaterials 2020, 10(7), 1419; https://doi.org/10.3390/nano10071419 - 21 Jul 2020

Cited by 25 | Viewed by 5812

Abstract

Soft actuators based on hydrogel materials, which can convert light energy directly into mechanical energy, are of the utmost importance, especially with enhancements in device development. However, the hunt for specific photothermal nanomaterials with distinct performance remains challenging. In this study, we successfully [...] Read more.

Soft actuators based on hydrogel materials, which can convert light energy directly into mechanical energy, are of the utmost importance, especially with enhancements in device development. However, the hunt for specific photothermal nanomaterials with distinct performance remains challenging. In this study, we successfully fabricated a bilayer hydrogel actuator consisting of an active photothermal layer from incorporated Ti₃C₂T_x MXene in poly(N-isopropylacrylamide) p(NIPAm)hydrogel structure and a passive layer from the N-(2-hydroxylethylpropyl)acrylamide (HEAA) hydrogel structure. The uniform and effective incorporation of MXene into the NIPAm hydrogel structures were characterized by a battery of techniques. The light responsive swelling properties of the MXene-embedded NIPAm-based hydrogel demonstrated fully reversible and repeatable behavior in the light on–off regime for up to ten consecutive cycles. The effect of MXene loading, the shape of the actuator, and the light source effects on the bilayer NIPAm-HEAA hydrogel structure were investigated. The bilayer hydrogel with MXene loading of 0.3% in the NIPAm hydrogel exhibited a 200% change of the bending angle in terms of its bidirectional shape/volume after 100 s exposure to white light at an intensity of 70 mW cm⁻². Additionally, the bending behavior under real sunlight was evaluated, showing the material’s potential applicability in practical environments. Full article

(This article belongs to the Special Issue Stimuli-Responsive Nanosystems Based on Polymers and Hybrid Nanoparticles)

► Show Figures

Figure 1

17 pages, 3114 KiB

Open AccessArticle

Toxicity to RAW264.7 Macrophages of Silica Nanoparticles and the E551 Food Additive, in Combination with Genotoxic Agents

by Fanny Dussert, Pierre-Adrien Arthaud, Marie-Edith Arnal, Bastien Dalzon, Anaëlle Torres, Thierry Douki, Nathalie Herlin, Thierry Rabilloud and Marie Carriere

Nanomaterials 2020, 10(7), 1418; https://doi.org/10.3390/nano10071418 - 21 Jul 2020

Cited by 21 | Viewed by 4060

Abstract

Synthetic amorphous silica (SAS) is used in a plethora of applications and included in many daily products to which humans are exposed via inhalation, ingestion, or skin contact. This poses the question of their potential toxicity, particularly towards macrophages, which show specific sensitivity [...] Read more.

Synthetic amorphous silica (SAS) is used in a plethora of applications and included in many daily products to which humans are exposed via inhalation, ingestion, or skin contact. This poses the question of their potential toxicity, particularly towards macrophages, which show specific sensitivity to this material. SAS represents an ideal candidate for the adsorption of environmental contaminants due to its large surface area and could consequently modulate their toxicity. In this study, we assessed the toxicity towards macrophages and intestinal epithelial cells of three SAS particles, either isolated SiO₂ nanoparticles (LS30) or SiO₂ particles composed of agglomerated-aggregates of fused primary particles, either food-grade (E551) or non-food-grade (Fumed silica). These particles were applied to cells either alone or in combination with genotoxic co-contaminants, i.e., benzo[a]pyrene (B[a]P) and methane methylsulfonate (MMS). We show that macrophages are much more sensitive to these toxic agents than a non-differenciated co-culture of Caco-2 and HT29-MTX cells, used here as a model of intestinal epithelium. Co-exposure to SiO₂ and MMS causes DNA damage in a synergistic way, which is not explained by the modulation of DNA repair protein mRNA expression. Together, this suggests that SiO₂ particles could adsorb genotoxic agents on their surface and, consequently, increase their DNA damaging potential. Full article

(This article belongs to the Special Issue Toxicology and Biocompatibility of Nanomaterials)

► Show Figures

Graphical abstract

17 pages, 7466 KiB

Open AccessArticle

On the Effect of Modified Carbohydrates on the Size and Shape of Gold and Silver Nanostructures

by Idris Yazgan, Abdurrahman Gümüş, Kutalmış Gökkuş, Mehmet Ali Demir, Senanur Evecen, Hamide Ayçin Sönmez, Roland M. Miller, Fatma Bakar, Ayhan Oral, Sergei Popov and Muhammet S. Toprak

Nanomaterials 2020, 10(7), 1417; https://doi.org/10.3390/nano10071417 - 21 Jul 2020

Cited by 16 | Viewed by 3563

Abstract

Gold (Au) and silver (Ag) nanostructures have widespread utilization from biomedicine to materials science. Therefore, their synthesis with control of their morphology and surface chemistry have been among the hot topics over the last decades. Here, we introduce a new approach relying on [...] Read more.

Gold (Au) and silver (Ag) nanostructures have widespread utilization from biomedicine to materials science. Therefore, their synthesis with control of their morphology and surface chemistry have been among the hot topics over the last decades. Here, we introduce a new approach relying on sugar derivatives that work as reducing, stabilizing, and capping agents in the synthesis of Au and Ag nanostructures. These sugar derivatives are utilized alone and as mixture, resulting in spherical, spheroid, trigonal, polygonic, and star-like morphologies. The synthesis approach was further tested in the presence of acetate and dimethylamine as size- and shape-directing agents. With the use of transmission electron microscopy (TEM), selected area electron diffraction (SAED), x-ray diffraction (XRD), scanning electron microscopy (SEM), and ultraviolet-visible (UV-vis) absorption spectroscopy techniques, the particle size, shape, assembly, aggregation, and film formation characteristics were evaluated. NPs’ attributes were shown to be tunable by manipulating the sugar ligand selection and sugar ligand/metal-ion ratio. For instance, with an imine side group and changing the sugar moiety from cellobiose to lactose, the morphology of the Ag nanoparticles (NPs) transformed from well dispersed cubic to rough and aggregated. The introduction of acetate and dimethylamine further extended the growth pattern and morphological properties of these NPs. As examples, L5 AS, G5AS, and S5AS ligands formed spherical or sheet-like structures when used alone, which upon the use of these additives transformed into larger multicore and rough NPs, revealing their significant effect on the NP morphology. Selected samples were tested for their stability against protein corona formation and ionic strength, where a high chemical stability and resistance to protein coating were observed. The findings show a promising, benign approach for the synthesis of shape- and size-directed Au and Ag nanostructures, along with a selection of the chemistry of carbohydrate-derivatives that can open new windows for their applications. Full article

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

► Show Figures

Graphical abstract

12 pages, 5608 KiB

Open AccessCommunication

New Mussel Inspired Polydopamine-Like Silica-Based Material for Dye Adsorption

by Marina Massaro, Vincenzo Campisciano, César Viseras Iborra, Leonarda F. Liotta, Manuel Sánchez-Polo, Serena Riela and Michelangelo Gruttadauria

Nanomaterials 2020, 10(7), 1416; https://doi.org/10.3390/nano10071416 - 20 Jul 2020

Cited by 7 | Viewed by 3085

Abstract

A straightforward and economic procedure has been developed for the synthesis of a new polydopamine-like silica-based material that has been obtained by oxidation of catechol with KIO₄ followed by reaction with 3-aminopropyltrimethoxysilane. All techniques adopted for characterization showed that the obtained material [...] Read more.

A straightforward and economic procedure has been developed for the synthesis of a new polydopamine-like silica-based material that has been obtained by oxidation of catechol with KIO₄ followed by reaction with 3-aminopropyltrimethoxysilane. All techniques adopted for characterization showed that the obtained material is rich in different functional groups and the morphological analyses revealed dimensions in the nanometric range. The hybrid material has been characterized by several techniques showing its polydopamine-like nature, and preliminary observations for dye adsorption have been reported. Full article

► Show Figures

Graphical abstract

21 pages, 14597 KiB

Open AccessArticle

Spectroscopic Properties of Si-nc in SiO_x Films Using HFCVD

by Zaira Jocelyn Hernández Simón, Jose Alberto Luna López, Alvaro David Hernández de la Luz, Sergio Alfonso Pérez García, Alfredo Benítez Lara, Godofredo García Salgado, Jesus Carrillo López, Gabriel Omar Mendoza Conde and Hayde Patricia Martínez Hernández

Nanomaterials 2020, 10(7), 1415; https://doi.org/10.3390/nano10071415 - 20 Jul 2020

Cited by 13 | Viewed by 3087

Abstract

In the present work, non-stoichiometric silicon oxide films (SiO_x) deposited using a hot filament chemical vapor deposition technique at short time and simple parameters of depositions are reported. This is motivated by the numerous potential applications of SiO_x films in [...] Read more.

In the present work, non-stoichiometric silicon oxide films (SiO_x) deposited using a hot filament chemical vapor deposition technique at short time and simple parameters of depositions are reported. This is motivated by the numerous potential applications of SiO_x films in areas such as optoelectronics. SiO_x films were characterized with different spectroscopic techniques. The deposited films have interesting characteristics such as the presence of silicon nanoclusters without applying thermal annealing, in addition to a strong photoluminescence after applying thermal annealing in the vicinity of 1.5 eV, which may be attributed to the presence of small, oxidized silicon grains (less than 2 nm) or silicon nanocrystals (Si-nc). An interesting correlation was found between oxygen content, the presence of hydrogen, and the formation of defects in the material, with parameters such as the band gap and the Urbach energies. This correlation is interesting in the development of band gap engineering for this material for applications in photonic devices. Full article

(This article belongs to the Special Issue Nano-Hybrids: Synthesis, Characterization and Applications)

► Show Figures

Figure 1

22 pages, 1223 KiB

Open AccessReview

Emerging Nanotechnology in Non-Surgical Periodontal Therapy in Animal Models: A Systematic Review

by Adrian Brun, Nicolas Moignot, Marie-Laure Colombier and Elisabeth Dursun

Nanomaterials 2020, 10(7), 1414; https://doi.org/10.3390/nano10071414 - 20 Jul 2020

Cited by 9 | Viewed by 3406

Abstract

Periodontitis is one of the most prevalent inflammatory diseases. Its treatment, mostly mechanical and non-surgical, shows limitations. The aim of this systematic review was to investigate the effect of nanoparticles as a treatment alone in non-surgical periodontal therapy in animal models. A systematic [...] Read more.

Periodontitis is one of the most prevalent inflammatory diseases. Its treatment, mostly mechanical and non-surgical, shows limitations. The aim of this systematic review was to investigate the effect of nanoparticles as a treatment alone in non-surgical periodontal therapy in animal models. A systematic search was conducted in Medline/PubMed, Web of Science, The Cochrane Library and Science Direct. The eligibility criteria were: studies (i) using nanoparticles as chemotherapeutic agent or as delivery system; (ii) including preclinical controlled animal model (experimental periodontitis); (iii) reporting alveolar bone loss; (iv) written in English; and (v) published up to June 2019. Risk of bias was evaluated according to the SYstematic Review Centre for Laboratory Animal Experimentation. On the 1324 eligible studies, 11 were included. All reported advantages in using nanoparticles for the treatment of periodontitis, highlighted by a reduction in bone loss. Agents modulating inflammation seem to be more relevant than antibiotics, in terms of efficiency and risk of antibiotic resistance. In addition, poly(lactic-co-glycolic acid) or drugs used as their own carrier appear to be the most interesting nanoparticles in terms of biocompatibility. Risk of bias assessment highlighted many criteria scored as unclear. There are encouraging preclinical data of using nanoparticles as a contribution to the treatment of periodontitis. Full article

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

► Show Figures

Figure 1

14 pages, 4689 KiB

Open AccessArticle

Kinetics of Hydrogen Generation from Oxidation of Hydrogenated Silicon Nanocrystals in Aqueous Solutions

by Gauhar Mussabek, Sergei A. Alekseev, Anton I. Manilov, Sergii Tutashkonko, Tetyana Nychyporuk, Yerkin Shabdan, Gulshat Amirkhanova, Sergei V. Litvinenko, Valeriy A. Skryshevsky and Vladimir Lysenko

Nanomaterials 2020, 10(7), 1413; https://doi.org/10.3390/nano10071413 - 20 Jul 2020

Cited by 20 | Viewed by 5795

Abstract

Hydrogen generation rate is one of the most important parameters which must be considered for the development of engineering solutions in the field of hydrogen energy applications. In this paper, the kinetics of hydrogen generation from oxidation of hydrogenated porous silicon nanopowders in [...] Read more.

Hydrogen generation rate is one of the most important parameters which must be considered for the development of engineering solutions in the field of hydrogen energy applications. In this paper, the kinetics of hydrogen generation from oxidation of hydrogenated porous silicon nanopowders in water are analyzed in detail. The splitting of the Si-H bonds of the nanopowders and water molecules during the oxidation reaction results in powerful hydrogen generation. The described technology is shown to be perfectly tunable and allows us to manage the kinetics by: (i) varying size distribution and porosity of silicon nanoparticles; (ii) chemical composition of oxidizing solutions; (iii) ambient temperature. In particular, hydrogen release below 0 °C is one of the significant advantages of such a technological way of performing hydrogen generation. Full article

(This article belongs to the Special Issue Photoactive Nanomaterials)

► Show Figures

Figure 1

12 pages, 3622 KiB

Open AccessArticle

Glass Ionomer Cement Modified by Resin with Incorporation of Nanohydroxyapatite: In Vitro Evaluation of Physical-Biological Properties

by Luis Eduardo Genaro, Giovana Anovazzi, Josimeri Hebling and Angela Cristina Cilense Zuanon

Nanomaterials 2020, 10(7), 1412; https://doi.org/10.3390/nano10071412 - 19 Jul 2020

Cited by 8 | Viewed by 3579

Abstract

Resin-modified glass ionomer cement (RMGIC) has important properties. However, like other restorative materials, it has limitations such as decreased biocompatibility. The incorporation of nanoparticles (NP) in the RMGIC resulted in improvements in some of its properties. The aim of this study was to [...] Read more.

Resin-modified glass ionomer cement (RMGIC) has important properties. However, like other restorative materials, it has limitations such as decreased biocompatibility. The incorporation of nanoparticles (NP) in the RMGIC resulted in improvements in some of its properties. The aim of this study was to evaluate the physical-biological properties of RMGIC with the addition of nanohydroxyapatite (HANP). Material and Methods: Vitremer RMGIC was used, incorporating HANP by amalgamator, vortex and manual techniques, totaling ten experimental groups. The distribution and dispersion of the HANP were evaluated qualitatively by field emission scanning electron microscope (SEM-FEG). The evaluation of image porosity (SEM-FEG) with the help of imageJ. Cell viability 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyl tetrazoline bromide (MTT) and cell morphology analyses were performed on MDPC-23 odontoblastoid cells at 24 and 72 h. Results: It was possible to observe good dispersion and distribution of HANP in the samples in all experimental groups. The incorporation of 5% HANP into the vortex stirred RMGIC resulted in fewer pores. The increase in the concentration of HANP was directly proportional to the decrease in cytotoxicity. Conclusions: It is concluded that the use of a vortex with the incorporation of 5% HANP is the most appropriate mixing technique when considering the smallest number of pores inside the material. A higher concentration of HANP resulted in better cell viability, suggesting that this association is promising for future studies of new restorative materials. Full article

(This article belongs to the Special Issue Nanotechnology for Environmental and Biomedical Research)

► Show Figures

Figure 1

27 pages, 3912 KiB

Open AccessFeature PaperArticle

Impact of the Interband Transitions in Gold and Silver on the Dynamics of Propagating and Localized Surface Plasmons

by Krystyna Kolwas and Anastasiya Derkachova

Nanomaterials 2020, 10(7), 1411; https://doi.org/10.3390/nano10071411 - 19 Jul 2020

Cited by 83 | Viewed by 7183

Abstract

Understanding and modeling of a surface-plasmon phenomenon on lossy metals interfaces based on simplified models of dielectric function lead to problems when confronted with reality. For a realistic description of lossy metals, such as gold and silver, in the optical range of the [...] Read more.

Understanding and modeling of a surface-plasmon phenomenon on lossy metals interfaces based on simplified models of dielectric function lead to problems when confronted with reality. For a realistic description of lossy metals, such as gold and silver, in the optical range of the electromagnetic spectrum and in the adjacent spectral ranges it is necessary to account not only for ohmic losses but also for the radiative losses resulting from the frequency-dependent interband transitions. We give a detailed analysis of Surface Plasmon Polaritons (SPPs) and Localized Surface Plasmons (LPSs) supported by such realistic metal/dielectric interfaces based on the dispersion relations both for flat and spherical gold and silver interfaces in the extended frequency and nanoparticle size ranges. The study reveals the region of anomalous dispersion for a silver flat interface in the near UV spectral range and high-quality factors for larger nanoparticles. We show that the frequency-dependent interband transition accounted in the dielectric function in a way allowing reproducing well the experimentally measured indexes of refraction does exert the pronounced impact not only on the properties of SPP and LSP for gold interfaces but also, with the weaker but not negligible impact, on the corresponding silver interfaces in the optical ranges and the adjacent spectral ranges. Full article

(This article belongs to the Special Issue Computational Modeling and Simulation for Nanomaterials, Nanotechnology, and Nanoscience)

► Show Figures

Graphical abstract

11 pages, 3157 KiB

Open AccessArticle

A Polarization-Insensitive and Wide-Angle Terahertz Absorber with Ring-Porous Patterned Graphene Metasurface

by Hongyang Shen, Fengxiang Liu, Chunyang Liu, Dong Zeng, Banghong Guo, Zhongchao Wei, Faqiang Wang, Chunhua Tan, Xuguang Huang and Hongyun Meng

Nanomaterials 2020, 10(7), 1410; https://doi.org/10.3390/nano10071410 - 19 Jul 2020

Cited by 24 | Viewed by 3256

Abstract

A broadband terahertz (THz) absorber, based on a graphene metasurface, which consists of a layer of ring-porous patterned structure array and a metallic mirror separated by an ultrathin SiO₂ dielectric layer, is proposed and studied by numerical simulation. The simulated results show [...] Read more.

A broadband terahertz (THz) absorber, based on a graphene metasurface, which consists of a layer of ring-porous patterned structure array and a metallic mirror separated by an ultrathin SiO₂ dielectric layer, is proposed and studied by numerical simulation. The simulated results show that the absorptivity of the absorber reaches 90% in the range of 0.91–1.86 THz, and the normalized bandwidth of the absorptivity is 68.6% under normal incidence. In the simulation, the effects of the geometric parameters of the structure on the absorption band have been investigated. The results show that the absorber is insensitive to the incident polarization angle for both transverse electric (TE) and transverse magnetic (TM) under normal incidence. In addition, the absorber is not sensitive to oblique incidence of the light source under TE polarization conditions, and has an approximately stable absorption bandwidth at the incident angle from 0° to 50°. The absorption band can be adjusted by changing the bias voltage of the graphene Fermi level without varying the nanostructure. Furthermore, we propose that a two-layer graphene structure with the same geometric parameters is separated by a dielectric layer of appropriate thickness. The simulated results show that the absorptivity of the two-layer absorber reaches 90% in the range of 0.83-2.04 THz and the normalized bandwidth of the absorptivity is 84.3% under normal incidence. Because of its excellent characteristics based on graphene metamaterial absorbers, it has an important application value in the field of subwavelength photonic devices. Full article

► Show Figures

Figure 1

26 pages, 4740 KiB

Open AccessArticle

Kinetic and Thermodynamic Studies on Synthesis of Mg-Doped LiMn₂O₄ Nanoparticles

by Aleksei Llusco, Mario Grageda and Svetlana Ushak

Nanomaterials 2020, 10(7), 1409; https://doi.org/10.3390/nano10071409 - 19 Jul 2020

Cited by 24 | Viewed by 4699

Abstract

In this work, a first study on kinetics and thermodynamics of thermal decomposition for synthesis of doped LiMn₂O₄ nanoparticles is presented. The effect of Mg doping concentration on thermal decomposition of synthesis precursors, prepared by ultrasound-assisted Pechini-type sol–gel process, and [...] Read more.

In this work, a first study on kinetics and thermodynamics of thermal decomposition for synthesis of doped LiMn₂O₄ nanoparticles is presented. The effect of Mg doping concentration on thermal decomposition of synthesis precursors, prepared by ultrasound-assisted Pechini-type sol–gel process, and its significance on nucleation and growth of Mg-doped LiMn₂O₄ nanoparticles was studied through a method based on separation of multistage processes in single-stage reactions by deconvolution and transition state theory. Four zones of thermal decomposition were identified: Dehydration, polymeric matrix decomposition, carbonate decomposition and spinel formation, and spinel decomposition. Kinetic and thermodynamic analysis focused on the second zone. First-order Avrami-Erofeev equation was selected as reaction model representing the polymer matrix thermal decomposition. Kinetic and thermodynamic parameters revealed that Mg doping causes an increase in thermal inertia on conversion rate, and CO₂ desorption was the limiting step for formation of thermodynamically stable spinel phases. Based on thermogravimetry experiments and the effect of Mg on thermal decomposition, an optimal two-stage heat treatment was determined for preparation of LiMg_xMn_2−xO₄ (x = 0.00, 0.02, 0.05, 0.10) nanocrystalline powders as promising cathode materials for lithium-ion batteries. Crystalline structure, morphology, and stoichiometry of synthesized powders were characterized by XRD, FE-SEM, and AAS, respectively. Full article

(This article belongs to the Special Issue Innovative Advanced Materials for Energy Storage and Beyond: Synthesis, Characterization and Applications)

► Show Figures

Figure 1

13 pages, 1585 KiB

Open AccessArticle

Carbonate Micromotors for Treatment of Construction Effluents

by Purnesh Chattopadhyay, Priyanka Sharan, Andrej Berndt and Juliane Simmchen

Nanomaterials 2020, 10(7), 1408; https://doi.org/10.3390/nano10071408 - 19 Jul 2020

Cited by 4 | Viewed by 3157

Abstract

Concrete in construction has recently gained media coverage for its negative CO₂ footprint, but this is not the only problem associated with its use. Due to its chemical composition, freshly poured concrete changes the pH of water coming in contact with the [...] Read more.

Concrete in construction has recently gained media coverage for its negative CO₂ footprint, but this is not the only problem associated with its use. Due to its chemical composition, freshly poured concrete changes the pH of water coming in contact with the surface to very alkaline values, requiring neutralization treatment before disposal. Conventional methods include the use of mineral acid or CO₂ pumps, causing high costs to building companies. In this paper, we present a micromotor based remediation strategy, which consists of carbonate particles half-coated with citric acid. To achieve this half coverage spray coating is used for the first time to design Janus structures. The motors propel diffusiophoretically due to a self-generated gradient formed as the acid coverage dissolves. The locally lower pH contributes to the dissolution of the carbonate body. These motors have been employed to study neutralization of diluted concrete wash water (CWW) at microscopic scale and we achieve visualization of the pH changes occurring in the vicinity of motors using anthocyanine as pH indicator dye. The effect of citric acid-carbonates hybrid on neutralization of real CWW on macroscopic scale has also been studied. In addition, all employed chemicals are cheap, non-toxic and do not leave any solid residues behind. Full article

(This article belongs to the Special Issue Advances in Micro/Nanomotors)

► Show Figures

Figure 1

26 pages, 2433 KiB

Open AccessReview

Carbon Nanohorn-Based Electrocatalysts for Energy Conversion

by Antonia Kagkoura and Nikos Tagmatarchis

Nanomaterials 2020, 10(7), 1407; https://doi.org/10.3390/nano10071407 - 19 Jul 2020

Cited by 23 | Viewed by 4080

Abstract

In the context of even more growing energy demands, the investigation of alternative environmentally friendly solutions, like fuel cells, is essential. Given their outstanding properties, carbon nanohorns (CNHs) have come forth as promising electrocatalysts within the nanocarbon family. Carbon nanohorns are conical nanostructures [...] Read more.

In the context of even more growing energy demands, the investigation of alternative environmentally friendly solutions, like fuel cells, is essential. Given their outstanding properties, carbon nanohorns (CNHs) have come forth as promising electrocatalysts within the nanocarbon family. Carbon nanohorns are conical nanostructures made of sp² carbon sheets that form aggregated superstructures during their synthesis. They require no metal catalyst during their preparation and they are inexpensively produced in industrial quantities, affording a favorable candidate for electrocatalytic reactions. The aim of this article is to provide a comprehensive overview regarding CNHs in the field of electrocatalysis and especially, in oxygen reduction, methanol oxidation, and hydrogen evolution, as well as oxygen evolution from water splitting, underlining the progress made so far, and pointing out the areas where significant improvement can be achieved. Full article

(This article belongs to the Special Issue 10th Anniversary of Nanomaterials—Recent Advances in Nanomaterials for Energy and Catalysis)

► Show Figures

Graphical abstract

30 pages, 9021 KiB

Open AccessReview

Glycan Nanobiosensors

by Filip Kveton, Anna Blsakova, Peter Kasak and Jan Tkac

Nanomaterials 2020, 10(7), 1406; https://doi.org/10.3390/nano10071406 - 19 Jul 2020

Cited by 19 | Viewed by 4904

Abstract

This review paper comprehensively summarizes advances made in the design of glycan nanobiosensors using diverse forms of nanomaterials. In particular, the paper covers the application of gold nanoparticles, quantum dots, magnetic nanoparticles, carbon nanoparticles, hybrid types of nanoparticles, proteins as nanoscaffolds and various [...] Read more.

This review paper comprehensively summarizes advances made in the design of glycan nanobiosensors using diverse forms of nanomaterials. In particular, the paper covers the application of gold nanoparticles, quantum dots, magnetic nanoparticles, carbon nanoparticles, hybrid types of nanoparticles, proteins as nanoscaffolds and various nanoscale-based approaches to designing such nanoscale probes. The article covers innovative immobilization strategies for the conjugation of glycans on nanoparticles. Summaries of the detection schemes applied, the analytes detected and the key operational characteristics of such nanobiosensors are provided in the form of tables for each particular type of nanomaterial. Full article

(This article belongs to the Special Issue Functional Glyconanomaterials)

► Show Figures

Figure 1

25 pages, 10065 KiB

Open AccessArticle

Effects of Functionalized Fullerenes on ROS Homeostasis Determine Their Cytoprotective or Cytotoxic Properties

by Svetlana V. Kostyuk, Elena V. Proskurnina, Ekaterina A. Savinova, Elizaveta S. Ershova, Olga A. Kraevaya, Larisa V. Kameneva, Pavel E. Umryukhin, Olga A. Dolgikh, Sergey I. Kutsev, Pavel A. Troshin and Natalia N. Veiko

Nanomaterials 2020, 10(7), 1405; https://doi.org/10.3390/nano10071405 - 19 Jul 2020

Cited by 9 | Viewed by 2988

Abstract

Background: Functionalized fullerenes (FF) can be considered regulators of intracellular reactive oxygen species (ROS) homeostasis; their direct oxidative damage—as well as regulation of oxidant enzymes and signaling pathways—should be considered. Methods: Uptake of two water-soluble functionalized C₇₀ fullerenes with different types of [...] Read more.

Background: Functionalized fullerenes (FF) can be considered regulators of intracellular reactive oxygen species (ROS) homeostasis; their direct oxidative damage—as well as regulation of oxidant enzymes and signaling pathways—should be considered. Methods: Uptake of two water-soluble functionalized C₇₀ fullerenes with different types of aromatic addends (ethylphenylmalonate and thienylacetate) in human fetal lung fibroblasts, intracellular ROS visualization, superoxide scavenging potential, NOX4 expression, NRF2 expression, oxidative DNA damage, repair genes, cell proliferation and cell cycle were studied. Results & conclusion: The intracellular effects of ethylphenylmalonate C₇₀ derivative (FF1) can be explained in terms of upregulated NOX4 activity. The intracellular effects of thienylacetate C₇₀ derivative (FF2) can be probably resulted from its superoxide scavenging potential and inhibition of lipid peroxidation. FF1 can be considered a NOX4 upregulator and potential cytotoxicant and FF2, as a superoxide scavenger and a potential cytoprotector. Full article

(This article belongs to the Special Issue Cytotoxicity and Genotoxicity of Nanomaterials)

► Show Figures

Graphical abstract

7 pages, 2878 KiB

Open AccessCommunication

Memtransistors Based on Nanopatterned Graphene Ferroelectric Field-Effect Transistors

by Mircea Dragoman, Adrian Dinescu, Florin Nastase and Daniela Dragoman

Nanomaterials 2020, 10(7), 1404; https://doi.org/10.3390/nano10071404 - 19 Jul 2020

Cited by 10 | Viewed by 3488

Abstract

The ultimate memristor, which acts as resistive memory and an artificial neural synapse, is made from a single atomic layer. In this manuscript, we present experimental evidence of the memristive properties of a nanopatterned ferroelectric graphene field-effect transistor (FET). The graphene FET has, [...] Read more.

The ultimate memristor, which acts as resistive memory and an artificial neural synapse, is made from a single atomic layer. In this manuscript, we present experimental evidence of the memristive properties of a nanopatterned ferroelectric graphene field-effect transistor (FET). The graphene FET has, as a channel, a graphene monolayer transferred onto an HfO₂-based ferroelectric material, the channel being nanopatterned with an array of holes with a diameter of 20 nm. Full article

(This article belongs to the Section Nanoelectronics, Nanosensors and Devices)

► Show Figures

Figure 1

41 pages, 2933 KiB

Open AccessReview

Polymeric Nanoparticles for Drug Delivery: Recent Developments and Future Prospects

by Belén Begines, Tamara Ortiz, María Pérez-Aranda, Guillermo Martínez, Manuel Merinero, Federico Argüelles-Arias and Ana Alcudia

Nanomaterials 2020, 10(7), 1403; https://doi.org/10.3390/nano10071403 - 19 Jul 2020

Cited by 554 | Viewed by 30007

Abstract

The complexity of some diseases—as well as the inherent toxicity of certain drugs—has led to an increasing interest in the development and optimization of drug-delivery systems. Polymeric nanoparticles stand out as a key tool to improve drug bioavailability or specific delivery at the [...] Read more.

The complexity of some diseases—as well as the inherent toxicity of certain drugs—has led to an increasing interest in the development and optimization of drug-delivery systems. Polymeric nanoparticles stand out as a key tool to improve drug bioavailability or specific delivery at the site of action. The versatility of polymers makes them potentially ideal for fulfilling the requirements of each particular drug-delivery system. In this review, a summary of the state-of-the-art panorama of polymeric nanoparticles as drug-delivery systems has been conducted, focusing mainly on those applications in which the corresponding disease involves an important morbidity, a considerable reduction in the life quality of patients—or even a high mortality. A revision of the use of polymeric nanoparticles for ocular drug delivery, for cancer diagnosis and treatment, as well as nutraceutical delivery, was carried out, and a short discussion about future prospects of these systems is included. Full article

(This article belongs to the Special Issue New Avenues of Research for Nanoparticle Drug Delivery Systems)

► Show Figures

Graphical abstract

10 pages, 1658 KiB

Open AccessArticle

Troponin Aptamer on an Atomically Flat Au Nanoplate Platform for Detection of Cardiac Troponin I

by Hyoban Lee, Hyungjun Youn, Ahreum Hwang, Hyunsoo Lee, Jeong Young Park, Weon Kim, Youngdong Yoo, Changill Ban, Taejoon Kang and Bongsoo Kim

Nanomaterials 2020, 10(7), 1402; https://doi.org/10.3390/nano10071402 - 18 Jul 2020

Cited by 19 | Viewed by 4493

Abstract

Well-ordered bioreceptors on atomically flat Au surfaces can be a high-performance biosensor. Cardiac troponin I proteins (cTnIs) have been regarded as a specific biomarker for acute myocardial infarction (AMI). Here, we report the accurate detection of cTnIs using an aptamer-immobilized Au nanoplate platform. [...] Read more.

Well-ordered bioreceptors on atomically flat Au surfaces can be a high-performance biosensor. Cardiac troponin I proteins (cTnIs) have been regarded as a specific biomarker for acute myocardial infarction (AMI). Here, we report the accurate detection of cTnIs using an aptamer-immobilized Au nanoplate platform. The single-crystalline and atomically flat Au nanoplate was characterized by atomic force microscopy. For the precise detection of cTnI, we immobilized an aptamer that can strongly bind to cTnI onto an atomically flat Au nanoplate. Using the aptamer-immobilized Au nanoplate, cTnIs were successfully detected at a concentration of 100 aM (2.4 fg/mL) in buffer solution. Furthermore, cTnIs in serum could be identified at a concentration of 100 fM (2.4 pg/mL). The total assay time was ~7 h. Importantly, the aptamer-immobilized Au nanoplate enabled us to diagnose AMI patients accurately, suggesting the potential of the present method in the diagnosis of AMI. Full article

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

► Show Figures

Graphical abstract

10 pages, 1253 KiB

Open AccessCommunication

Nanotoxicity of ZrS₃ Probed in a Bioluminescence Test on E. coli Bacteria: The Effect of Evolving H₂S

by Olga V. Zakharova, Alexander A. Gusev, Jehad Abourahma, Nataliia S. Vorobeva, Dmitry V. Sokolov, Dmitry S. Muratov, Denis V. Kuznetsov and Alexander Sinitskii

Nanomaterials 2020, 10(7), 1401; https://doi.org/10.3390/nano10071401 - 18 Jul 2020

Cited by 9 | Viewed by 3170

Abstract

Materials from a large family of transition metal trichalcogenides (TMTCs) attract considerable attention because of their potential applications in electronics, optoelectronics and energy storage, but information on their toxicity is lacking. In this study, we investigated the toxicity of ZrS₃, a [...] Read more.

Materials from a large family of transition metal trichalcogenides (TMTCs) attract considerable attention because of their potential applications in electronics, optoelectronics and energy storage, but information on their toxicity is lacking. In this study, we investigated the toxicity of ZrS₃, a prominent TMTC material, toward photoluminescent E. coli bacteria in a bioluminescence test. We found that freshly prepared ZrS₃ suspensions in physiological saline solution with concentrations as high as 1 g/L did not exhibit any toxic effects on the bacteria. However, ZrS₃ suspensions that were stored for 24 h prior to the bioluminescence tests were very toxic to the bacteria and inhibited their emission, even at concentrations down to 0.001 g/L. We explain these observations by the aqueous hydrolysis of ZrS₃, which resulted in the formation of ZrO_x on the surface of ZrS₃ particles and the release of toxic H₂S. The formation of ZrO_x was confirmed by the XPS analysis, while the characteristic H₂S smell was noticeable for the 24 h suspensions. This study demonstrates that while ZrS₃ appears to be intrinsically nontoxic to photoluminescent E. coli bacteria, it may exhibit high toxicity in aqueous media. The results of this study can likely be extended to other transition metal chalcogenides, as their toxicity in aqueous solutions may also increase over time due to hydrolysis and the formation of H₂S. The results of this study also demonstrate that since many systems involving nanomaterials are unstable and evolve over time in various ways, their toxicity may evolve as well, which should be considered for relevant toxicity tests. Full article

(This article belongs to the Special Issue Frontiers in Nanotoxicology)

► Show Figures

Figure 1

16 pages, 3883 KiB

Open AccessArticle

Mucoadhesive Nanoparticles for Drug Delivery to the Anterior Eye

by Nicole Mangiacotte, Graeme Prosperi-Porta, Lina Liu, Megan Dodd and Heather Sheardown

Nanomaterials 2020, 10(7), 1400; https://doi.org/10.3390/nano10071400 - 18 Jul 2020

Cited by 8 | Viewed by 3949

Abstract

While the use of topical drops for the delivery of drugs to the anterior of the eye is well accepted, it is far from efficient with as little as 5% of the drug instilled on the eye actually reaching the target tissue. The [...] Read more.

While the use of topical drops for the delivery of drugs to the anterior of the eye is well accepted, it is far from efficient with as little as 5% of the drug instilled on the eye actually reaching the target tissue. The ability to prolong the residence time on the eye is desirable. Based on the acceptability of 2-hydroxyethyl methacrylate based polymers in contact lens applications, the current work focuses on the development of a poly(2-hydroxyethyl methacrylate (HEMA)) nanoparticle system. The particles were modified to allow for degradation and to permit mucoadhesion. Size and morphological analysis of the final polymer products showed that nano-sized, spherical particles were produced. FTIR spectra demonstrated that the nanoparticles comprised poly(HEMA) and that 3-(acrylamido)phenylboronic acid (3AAPBA), as a mucoadhesive, was successfully incorporated. Degradation of nanoparticles containing N,N′-bis(acryloyl)cystamine (BAC) after incubation with DL-dithiothreitol (DTT) was confirmed by a decrease in turbidity and through transmission electron microscopy (TEM). Nanoparticle mucoadhesion was shown through an in-vitro zeta potential analysis. Full article

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

► Show Figures

Figure 1

14 pages, 2823 KiB

Open AccessArticle

Highly Sensitive and Tunable Plasmonic Sensor Based on a Nanoring Resonator with Silver Nanorods

by Chung-Ting Chou Chao, Yuan-Fong Chou Chau, Hung Ji Huang, N. T. R. N. Kumara, Muhammad Raziq Rahimi Kooh, Chee Ming Lim and Hai-Pang Chiang

Nanomaterials 2020, 10(7), 1399; https://doi.org/10.3390/nano10071399 - 18 Jul 2020

Cited by 76 | Viewed by 4578

Abstract

We numerically and theoretically investigate a highly sensitive and tunable plasmonic refractive index sensor that is composed of a metal-insulator-metal waveguide with a side-coupled nanoring, containing silver nanorods using the finite element method. Results reveal that the presence of silver nanorods in the [...] Read more.

We numerically and theoretically investigate a highly sensitive and tunable plasmonic refractive index sensor that is composed of a metal-insulator-metal waveguide with a side-coupled nanoring, containing silver nanorods using the finite element method. Results reveal that the presence of silver nanorods in the nanoring has a significant impact on sensitivity and tunability performance. It gives a flexible way to tune the system response in the proposed structure. Our designed sensor has a sensitivity of 2080 nm/RIU (RIU is the refractive index unit) along with a figure of merit and a quality factor of 29.92 and 29.67, respectively. The adequate refractive index sensitivity can increase by adding the silver nanorods in a nanoring, which can induce new surface plasmon polaritons (SPPs) modes that cannot be found by a regular nanoring. For a practical application, a valid introduction of silver nanorods in the nanoring can dramatically reduce the dimension of the proposed structure without sacrificing performance. Full article

(This article belongs to the Special Issue Nanobiophotonics, Photomedicine, and Imaging)

► Show Figures

Figure 1

22 pages, 3264 KiB

Open AccessReview

Sustainable Biomass Activated Carbons as Electrodes for Battery and Supercapacitors—A Mini-Review

by Glaydson Simões dos Reis, Sylvia H. Larsson, Helinando Pequeno de Oliveira, Mikael Thyrel and Eder Claudio Lima

Nanomaterials 2020, 10(7), 1398; https://doi.org/10.3390/nano10071398 - 18 Jul 2020

Cited by 85 | Viewed by 7164

Abstract

Some recent developments in the preparation of biomass carbon electrodes (CEs) using various biomass residues for application in energy storage devices, such as batteries and supercapacitors, are presented in this work. The application of biomass residues as the primary precursor for the production [...] Read more.

Some recent developments in the preparation of biomass carbon electrodes (CEs) using various biomass residues for application in energy storage devices, such as batteries and supercapacitors, are presented in this work. The application of biomass residues as the primary precursor for the production of CEs has been increasing over the last years due to it being a renewable source with comparably low processing cost, providing prerequisites for a process that is economically and technically sustainable. Electrochemical energy storage technology is key to the sustainable development of autonomous and wearable electronic devices. This article highlights the application of various types of biomass in the production of CEs by using different types of pyrolysis and experimental conditions and denotes some possible effects on their final characteristics. An overview is provided on the use of different biomass types for the synthesis of CEs with efficient electrochemical properties for batteries and supercapacitors. This review showed that, from different biomass residues, it is possible to obtain CEs with different electrochemical properties and that they can be successfully applied in high-performance batteries and supercapacitors. As the research and development of producing CEs still faces a gap by linking the type and composition of biomass residues with the carbon electrodes’ electrochemical performances in supercapacitor and battery applications, this work tries to diminish this gap. Physical and chemical characteristics of the CEs, such as porosity, chemical composition, and surface functionalities, are reflected in the electrochemical performances. It is expected that this review not only provides the reader with a good overview of using various biomass residues in the energy storage applications, but also highlights some goals and challenges remaining in the future research and development of this topic. Full article

(This article belongs to the Special Issue Innovative Advanced Materials for Energy Storage and Beyond: Synthesis, Characterization and Applications)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Nanomaterials, Volume 10, Issue 7 (July 2020) – 180 articles

Further Information

Guidelines

MDPI Initiatives

Follow MDPI