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15 pages, 6165 KiB

Open AccessArticle

Coagulation Treatment of Wastewater: Kinetics and Natural Coagulant Evaluation

by Nomthandazo Precious Sibiya, Sudesh Rathilal and Emmanuel Kweinor Tetteh

Molecules 2021, 26(3), 698; https://doi.org/10.3390/molecules26030698 - 29 Jan 2021

Cited by 66 | Viewed by 6374

Abstract

In this study, three coagulants (ferromagnetite (F), alum (A), and eggshells (E)) and their hybrids (FA, FE, and FEA) were investigated as possible cost-effective coagulants for the treatment of industrial wastewater. Scanning electron microscopy (SEM) coupled with energy-dispersive X-ray (EDX) was used to [...] Read more.

In this study, three coagulants (ferromagnetite (F), alum (A), and eggshells (E)) and their hybrids (FA, FE, and FEA) were investigated as possible cost-effective coagulants for the treatment of industrial wastewater. Scanning electron microscopy (SEM) coupled with energy-dispersive X-ray (EDX) was used to characterize the morphological and elemental compositions of the coagulants. The effects of coagulant dosage (10–60 mg/L) and settling time were investigated for the removal of turbidity, color, and total suspended solids. A jar tester (JTL6) operating at conditions of 150 rpm for 2 min (rapid mixing) and 30 rpm for 15 min (slow mixing) was employed. Results from the characterized supernatant showed about 80% removal of the contaminants. The prospects of F were proven to be the most effective as compared to the binary (FA > FE) and the ternary hybridized (FEA) coagulants. At an optimum dosage and settling time of 20 mg/L and 30 min, respectively, the treatability performance of F was clearly proven to be viable for wastewater treatment. Full article

(This article belongs to the Special Issue 25th Anniversary of Molecules—Recent Advances in Nanochemistry)

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15 pages, 1327 KiB

Open AccessArticle

Enzyme Stability in Nanoparticle Preparations Part 1: Bovine Serum Albumin Improves Enzyme Function

by Jason Thomas Duskey, Federica da Ros, Ilaria Ottonelli, Barbara Zambelli, Maria Angela Vandelli, Giovanni Tosi and Barbara Ruozi

Molecules 2020, 25(20), 4593; https://doi.org/10.3390/molecules25204593 - 9 Oct 2020

Cited by 20 | Viewed by 3387

Abstract

Enzymes have gained attention for their role in numerous disease states, calling for research for their efficient delivery. Loading enzymes into polymeric nanoparticles to improve biodistribution, stability, and targeting in vivo has led the field with promising results, but these enzymes still suffer [...] Read more.

Enzymes have gained attention for their role in numerous disease states, calling for research for their efficient delivery. Loading enzymes into polymeric nanoparticles to improve biodistribution, stability, and targeting in vivo has led the field with promising results, but these enzymes still suffer from a degradation effect during the formulation process that leads to lower kinetics and specific activity leading to a loss of therapeutic potential. Stabilizers, such as bovine serum albumin (BSA), can be beneficial, but the knowledge and understanding of their interaction with enzymes are not fully elucidated. To this end, the interaction of BSA with a model enzyme B-Glu, part of the hydrolase class and linked to Gaucher disease, was analyzed. To quantify the natural interaction of beta-glucosidase (B-Glu,) and BSA in solution, isothermal titration calorimetry (ITC) analysis was performed. Afterwards, polymeric nanoparticles encapsulating these complexes were fully characterized, and the encapsulation efficiency, activity of the encapsulated enzyme, and release kinetics of the enzyme were compared. ITC results showed that a natural binding of 1:1 was seen between B-Glu and BSA. Complex concentrations did not affect nanoparticle characteristics which maintained a size between 250 and 350 nm, but increased loading capacity (from 6% to 30%), enzyme activity, and extended-release kinetics (from less than one day to six days) were observed for particles containing higher B-Glu:BSA ratios. These results highlight the importance of understanding enzyme:stabilizer interactions in various nanoparticle systems to improve not only enzyme activity but also biodistribution and release kinetics for improved therapeutic effects. These results will be critical to fully characterize and compare the effect of stabilizers, such as BSA with other, more relevant therapeutic enzymes for central nervous system (CNS) disease treatments. Full article

(This article belongs to the Special Issue 25th Anniversary of Molecules—Recent Advances in Nanochemistry)

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14 pages, 6775 KiB

Open AccessArticle

Fabrication and Performance of Self-Supported Flexible Cellulose Nanofibrils/Reduced Graphene Oxide Supercapacitor Electrode Materials

by Wen He, Bo Wu, Mengting Lu, Ze Li and Han Qiang

Molecules 2020, 25(12), 2793; https://doi.org/10.3390/molecules25122793 - 17 Jun 2020

Cited by 27 | Viewed by 3490

Abstract

With the rapid development of portable and wearable electronic devices, self-supporting flexible supercapacitors have attracted much attention, and higher requirements have been put forward for the electrode of the device, that is, it is necessary to have good mechanical properties while satisfying excellent [...] Read more.

With the rapid development of portable and wearable electronic devices, self-supporting flexible supercapacitors have attracted much attention, and higher requirements have been put forward for the electrode of the device, that is, it is necessary to have good mechanical properties while satisfying excellent electrochemical performance. In this work, a facile method was invented to obtain excellent self-supported flexible electrode materials with high mechanical properties and outstanding electrochemical performance by combining cellulose nanofibrils (CNFs) and reduced graphene oxide (RGO). We focused on the effect of the ratio of the addition of CNFs and the formation process of the film on the electrochemical and mechanical properties. The results show that the CNFs/RGO₁₂ (where the ratio of CNFs to GO is 1:2) film displayed outstanding comprehensive properties; its tensile strength and conductivity were up to 83 MPa and 202.94 S/m, respectively, and its C_A value was as high as 146 mF cm⁻² under the current density of 5 mA cm⁻². Furthermore, the initial retention rate of the specific capacitance was about 83.7% when recycled 2000 times; moreover, its capacitance did not change much after perpendicular bending 200 times. Therefore, the films prepared by this study have great potential in the field of flexible supercapacitors. Full article

(This article belongs to the Special Issue 25th Anniversary of Molecules—Recent Advances in Nanochemistry)

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14 pages, 4307 KiB

Open AccessArticle

Enzyme Mimetic Activity of ZnO-Pd Nanosheets Synthesized via a Green Route

by Ravi Mani Tripathi, Dohee Ahn, Yeong Mok Kim and Sang J. Chung

Molecules 2020, 25(11), 2585; https://doi.org/10.3390/molecules25112585 - 2 Jun 2020

Cited by 26 | Viewed by 3047

Abstract

Recent developments in the area of nanotechnology have focused on the development of nanomaterials with catalytic activities. The enzyme mimics, nanozymes, work efficiently in extreme pH and temperature conditions, and exhibit resistance to protease digestion, in contrast to enzymes. We developed an environment-friendly, [...] Read more.

Recent developments in the area of nanotechnology have focused on the development of nanomaterials with catalytic activities. The enzyme mimics, nanozymes, work efficiently in extreme pH and temperature conditions, and exhibit resistance to protease digestion, in contrast to enzymes. We developed an environment-friendly, cost-effective, and facile biological method for the synthesis of ZnO-Pd nanosheets. This is the first biosynthesis of ZnO-Pd nanosheets. The synthesized nanosheets were characterized by UV–visible spectroscopy, X-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray. The d-spacing (inter-atomic spacing) of the palladium nanoparticles in the ZnO sheets was found to be 0.22 nm, which corresponds to the (111) plane. The XRD pattern revealed that the 2θ values of 21.8°, 33.3°, 47.7°, and 56.2° corresponded with the crystal planes of (100), (002), (112), and (201), respectively. The nanosheets were validated to possess peroxidase mimetic activity, which oxidized the 3,3′,5,5′-tetramethylbenzidine (TMB) substrate in the presence of H₂O₂. After 20 min of incubation time, the colorless TMB substrate oxidized into a dark-blue-colored one and a strong peak was observed at 650 nm. The initial velocities of Pd-ZnO-catalyzed TMB oxidation by H₂O₂ were analyzed by Michaelis–Menten and Lineweaver–Burk plots, resulting in 64 × 10⁻⁶ M, 8.72 × 10⁻⁹ Msec⁻¹, and 8.72 × 10⁻⁴ sec⁻¹ of K_M, V_max, and k_cat, respectively. Full article

(This article belongs to the Special Issue 25th Anniversary of Molecules—Recent Advances in Nanochemistry)

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22 pages, 6209 KiB

Open AccessArticle

Synthesis of Chitosan Beads Incorporating Graphene Oxide/Titanium Dioxide Nanoparticles for In Vivo Studies

by Carlos David Grande Tovar, Jorge Iván Castro, Carlos Humberto Valencia, Paula A. Zapata, Moisés A. Solano, Edwin Florez López, Manuel N. Chaur, Mayra Eliana Valencia Zapata and José Herminsul Mina Hernandez

Molecules 2020, 25(10), 2308; https://doi.org/10.3390/molecules25102308 - 14 May 2020

Cited by 11 | Viewed by 4415

Abstract

Scaffold development for cell regeneration has increased in recent years due to the high demand for more efficient and biocompatible materials. Nanomaterials have become a critical alternative for mechanical, thermal, and antimicrobial property reinforcement in several biopolymers. In this work, four different chitosan [...] Read more.

Scaffold development for cell regeneration has increased in recent years due to the high demand for more efficient and biocompatible materials. Nanomaterials have become a critical alternative for mechanical, thermal, and antimicrobial property reinforcement in several biopolymers. In this work, four different chitosan (CS) bead formulations crosslinked with glutaraldehyde (GLA), including titanium dioxide nanoparticles (TiO₂), and graphene oxide (GO) nanosheets, were prepared with potential biomedical applications in mind. The characterization of by FTIR spectroscopy, X-ray photoelectron spectroscopy (XRD), thermogravimetric analysis (TGA), energy-dispersive spectroscopy (EDS) and scanning electron microscopy (SEM), demonstrated an efficient preparation of nanocomposites, with nanoparticles well-dispersed in the polymer matrix. In vivo, subdermal implantation of the beads in Wistar rat′s tissue for 90 days showed a proper and complete healing process without any allergenic response to any of the formulations. Masson′s trichrome staining of the histological implanted tissues demonstrated the presence of a group of macrophage/histiocyte compatible cells, which indicates a high degree of biocompatibility of the beads. The materials were very stable under body conditions as the morphometry studies showed, but with low resorption percentages. These high stability beads could be used as biocompatible, resistant materials for long-term applications. The results presented in this study show the enormous potential of these chitosan nanocomposites in cell regeneration and biomedical applications. Full article

(This article belongs to the Special Issue 25th Anniversary of Molecules—Recent Advances in Nanochemistry)

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11 pages, 2146 KiB

Open AccessArticle

Fabrication of High-Performance Bamboo–Plastic Composites Reinforced by Natural Halloysite Nanotubes

by Xiaobei Jin, Jingpeng Li, Rong Zhang, Zehui Jiang and Daochun Qin

Molecules 2020, 25(9), 2259; https://doi.org/10.3390/molecules25092259 - 11 May 2020

Cited by 7 | Viewed by 2957

Abstract

Bamboo-plastic composites (BPCs) as new biomass-plastic composites have recently attracted much attention. However, weak mechanical performance and high moisture absorption as well as low thermal stability greatly limit their industrial applications. In this context, different amounts of halloysite nanotubes (HNTs) were used as [...] Read more.

Bamboo-plastic composites (BPCs) as new biomass-plastic composites have recently attracted much attention. However, weak mechanical performance and high moisture absorption as well as low thermal stability greatly limit their industrial applications. In this context, different amounts of halloysite nanotubes (HNTs) were used as a natural reinforcing filler for BPCs. It was found that the thermal stability of BPCs increased with increasing HNT contents. The mechanical strength of BPCs was improved with the increase in HNT loading up to 4 wt% and then worsened, while the impact strengths were slightly reduced. Low HNT content (below 4 wt%) also improved the dynamic thermomechanical properties and reduced the water absorption of the BPCs. Morphological studies confirmed the improved interfacial compatibility of the BPC matrix with 4 wt% HNT loading, and high-concentration HNT loading (above 6 wt%) resulted in easy agglomeration. The results highlight that HNTs could be a feasible candidate as nanoreinforcements for the development of high-performance BPCs. Full article

(This article belongs to the Special Issue 25th Anniversary of Molecules—Recent Advances in Nanochemistry)

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13 pages, 5022 KiB

Open AccessArticle

Nanostructured ZnO/Ag Film Prepared by Magnetron Sputtering Method for Fast Response of Ammonia Gas Detection

by Yiran Zheng, Min Li, Xiaoyan Wen, Ho-Pui Ho and Haifei Lu

Molecules 2020, 25(8), 1899; https://doi.org/10.3390/molecules25081899 - 20 Apr 2020

Cited by 7 | Viewed by 3423

Abstract

Possessing a large surface-to-volume ratio is significant to the sensitive gas detection of semiconductor nanostructures. Here, we propose a fast-response ammonia gas sensor based on porous nanostructured zinc oxide (ZnO) film, which is fabricated through physical vapor deposition and subsequent thermal annealing. In [...] Read more.

Possessing a large surface-to-volume ratio is significant to the sensitive gas detection of semiconductor nanostructures. Here, we propose a fast-response ammonia gas sensor based on porous nanostructured zinc oxide (ZnO) film, which is fabricated through physical vapor deposition and subsequent thermal annealing. In general, an extremely thin silver (Ag) layer (1, 3, 5 nm) and a 100 nm ZnO film are sequentially deposited on the SiO₂/Si substrate by a magnetron sputtering method. The porous nanostructure of ZnO film is formed after thermal annealing contributed by the diffusion of Ag among ZnO crystal grains and the expansion of the ZnO film. Different thicknesses of the Ag layer help the formation of different sizes and quantities of hollows uniformly distributed in the ZnO film, which is demonstrated to hold superior gas sensing abilities than the compact ZnO film. The responses of the different porous ZnO films were also investigated in the ammonia concentration range of 10 to 300 ppm. Experimental results demonstrate that the ZnO/Ag(3 nm) sensor possesses a good electrical resistance variation of 85.74% after exposing the sample to 300 ppm ammonia gas for 310 s. Interestingly, a fast response of 61.18% in 60 s for 300 ppm ammonia gas has been achieved from the ZnO/Ag(5 nm) sensor, which costs only 6 s for the response increase to 10%. Therefore, this controllable, porous, nanostructured ZnO film maintaining a sensitive gas response, fabricated by the physical deposition approach, will be of great interest to the gas-sensing community. Full article

(This article belongs to the Special Issue 25th Anniversary of Molecules—Recent Advances in Nanochemistry)

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11 pages, 4430 KiB

Open AccessArticle

The Large-Scale Preparation and Optical Properties of MoS₂/WS₂ Vertical Hetero-Junction

by Tao Han, Hongxia Liu, Shulong Wang, Shupeng Chen and Kun Yang

Molecules 2020, 25(8), 1857; https://doi.org/10.3390/molecules25081857 - 17 Apr 2020

Cited by 8 | Viewed by 3719

Abstract

A variety of hetero-junctions can be constructed to form the basic structural units in the different optoelectronic devices, such as the photo-detectors, solar cells, sensors and light-emitting diodes. In our research, the large-area high-quality MoS₂/WS₂ vertical hetero-junction are prepared by [...] Read more.

A variety of hetero-junctions can be constructed to form the basic structural units in the different optoelectronic devices, such as the photo-detectors, solar cells, sensors and light-emitting diodes. In our research, the large-area high-quality MoS₂/WS₂ vertical hetero-junction are prepared by the two-step atmospheric pressure chemical vapor deposition (APCVD) methods and the dry transfer method, and the corresponding optimal reaction conditions of MoS₂/WS₂ vertical hetero-junction are obtained. The morphology, composition and optical properties of MoS₂/WS₂ vertical hetero-junction are systematically characterized by the optical microscopy, Raman spectroscopy, photoluminescence spectroscopy, atomic force microscopy and the field emission scanning electron microscopy. Compared to the mechanical transfer method, the MoS₂/WS₂ vertical hetero-junction sample obtained by the APCVD and dry transfer methods have lower impurity content, cleaner interfaces and tighter interlayer coupling. Besides, the strong interlayer coupling and effective interlayer charge transfer of MoS₂/WS₂ vertical hetero-junction are also further studied. The photoluminescence intensity of MoS₂/WS₂ vertical hetero-junction is significantly reduced compared to the single MoS₂ or WS₂ material. In general, this research can help to achieve the large-scale preparation of various Van der Waals hetero-junctions, which can lay the foundation for the new application of optoelectronic devices. Full article

(This article belongs to the Special Issue 25th Anniversary of Molecules—Recent Advances in Nanochemistry)

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8 pages, 2223 KiB

Open AccessCommunication

New Acidic Precursor and Acetone-Based Solvent for Fast Perovskite Processing via Proton-Exchange Reaction with Methylamine

by Sergey A. Fateev, Ekaterina I. Marchenko, Andrey A. Petrov, Eugene A. Goodilin and Alexey B. Tarasov

Molecules 2020, 25(8), 1856; https://doi.org/10.3390/molecules25081856 - 17 Apr 2020

Cited by 5 | Viewed by 3665

Abstract

A new solvent system for PbI₂ based on HI solution in acetone with a low boiling point is proposed. High solubility of PbI₂ is caused by the formation of iodoplumbate complexes, and reaches a concentration of 1.6 M. Upon its crystallization [...] Read more.

A new solvent system for PbI₂ based on HI solution in acetone with a low boiling point is proposed. High solubility of PbI₂ is caused by the formation of iodoplumbate complexes, and reaches a concentration of 1.6 M. Upon its crystallization metastable solvate phases PbI₂∙HI∙n{(CH₃)₂CO} are formed. The latter allows for their easy deposition on substrates in a form of smooth and uniform thin films by spin-coating. Through a fast acid-base reaction with a gaseous amine, the films of the intermediate phase can be completely converted to single-phase perovskite films. The developed method allows one to form smooth perovskite films with high crystallinity with a thickness up to 1 μm. Due to easy and fast processing, the developed method can be promising for perovskite technology upscaling. Full article

(This article belongs to the Special Issue 25th Anniversary of Molecules—Recent Advances in Nanochemistry)

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11 pages, 2440 KiB

Open AccessArticle

Quasi-Periodic Dendritic Metasurface for Integral Operation in Visible Light

by Huan Chen, Di An and Xiaopeng Zhao

Molecules 2020, 25(7), 1664; https://doi.org/10.3390/molecules25071664 - 4 Apr 2020

Cited by 6 | Viewed by 2513

Abstract

A reflective metasurface model composed of silver dendritic units is designed in this study. The integral property of this metasurface, which consists of an upper layer of dendritic structures, a silica spacer, and a bottom silver substrate was demonstrated at visible wavelengths. The [...] Read more.

A reflective metasurface model composed of silver dendritic units is designed in this study. The integral property of this metasurface, which consists of an upper layer of dendritic structures, a silica spacer, and a bottom silver substrate was demonstrated at visible wavelengths. The simulation results revealed that the metasurface can perform integral operation in the yellow and red bands; this can be easily generalized to the infrared and communication bands by scaling the transverse dimensions of this metasurface. A dendritic metasurface sample responding to red light was prepared via the bottom-up electrochemical deposition method. The integral operation property of the sample was verified experimentally. This dendritic metasurface, which can perform integral operation in visible light, can be used for big data processing technology, real-time signal processing, and beam shaping, and provides a new method for miniaturized and integrated all-optical signal processing systems. Full article

(This article belongs to the Special Issue 25th Anniversary of Molecules—Recent Advances in Nanochemistry)

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21 pages, 6385 KiB

Open AccessArticle

Synthesis and Characterization of Silica-Coated Oxyhydroxide Aluminum/Doped Polymer Nanocomposites: A Comparative Study and Its Application as a Sorbent

by Inas A. Ahmed, H. S. Hussein, Ahmed H. Ragab and Najlaa S. Al-Radadi

Molecules 2020, 25(7), 1520; https://doi.org/10.3390/molecules25071520 - 27 Mar 2020

Cited by 12 | Viewed by 3926

Abstract

The present investigation is a comparison study of two nanocomposites: Nano-silica-coated oxyhydroxide aluminum (SiO₂–AlOOH; SCB) and nano-silica-coated oxyhydroxide aluminum doped with polyaniline (SiO₂–AlOOH–PANI; SBDP). The prepared nanocomposites were evaluated by monitoring the elimination of heavy metal Ni(II) ions from [...] Read more.

The present investigation is a comparison study of two nanocomposites: Nano-silica-coated oxyhydroxide aluminum (SiO₂–AlOOH; SCB) and nano-silica-coated oxyhydroxide aluminum doped with polyaniline (SiO₂–AlOOH–PANI; SBDP). The prepared nanocomposites were evaluated by monitoring the elimination of heavy metal Ni(II) ions from aquatic solutions. The synthesized nanocomposites were analyzed and described by applying scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FTIR) techniques, as well as Zeta potential distribution. In this study, two adsorbents were applied to investigate their adsorptive capacity to eliminate Ni(II) ions from aqueous solution. The obtained results revealed that SBDP nanocomposite has a higher negative zeta potential value (−47.2 mV) compared with SCB nanocomposite (−39.4 mV). The optimum adsorption was performed at pH 8, with approximately 94% adsorption for SCB and 97% adsorption for SBDP nanocomposites. The kinetics adsorption of Ni ions onto SCB and SBDP nanocomposites was studied by applying the pseudo first-order, pseudo second-order, and Mories–Weber models. The data revealed that the adsorption of Ni ions onto SCB and SBDP nanocomposites followed the pseudo second-order kinetic model. The equilibrium adsorption data were analyzed using three models: Langmuir, Freundlich, and Dubinin–Radusekevisch–Kanager Isotherm. It was concluded that the Langmuir isotherm fits the experimental results well for the SCB and SBDP nanocomposites. Thermodynamic data revealed that the adsorption process using SCB nanocomposites is an endothermic and spontaneous reaction. Meanwhile, the Ni ion sorption on SBDP nanocomposites is exothermic and spontaneous reaction. Full article

(This article belongs to the Special Issue 25th Anniversary of Molecules—Recent Advances in Nanochemistry)

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15 pages, 4104 KiB

Open AccessArticle

In Vitro Bioactivity and Biocompatibility of Bio-Inspired Ti-6Al-4V Alloy Surfaces Modified by Combined Laser Micro/Nano Structuring

by Chen Li, Yong Yang, Lijun Yang, Zhen Shi, Pengfei Yang and Guanghua Cheng

Molecules 2020, 25(7), 1494; https://doi.org/10.3390/molecules25071494 - 25 Mar 2020

Cited by 26 | Viewed by 3746

Abstract

The bioactivity and biocompatibility play key roles in the success of dental and orthopaedic implants. Although most commercial implant systems use various surface microstructures, the ideal multi-scale topographies capable of controlling osteointegration have not yielded conclusive results. Inspired by both the isotropic adhesion [...] Read more.

The bioactivity and biocompatibility play key roles in the success of dental and orthopaedic implants. Although most commercial implant systems use various surface microstructures, the ideal multi-scale topographies capable of controlling osteointegration have not yielded conclusive results. Inspired by both the isotropic adhesion of the skin structures in tree frog toe pads and the anisotropic adhesion of the corrugated ridges on the scales of Morpho butterfly wings, composite micro/nano-structures, including the array of micro-hexagons and oriented nano-ripples on titanium alloy implants, were respectively fabricated by microsecond laser direct writing and femtosecond laser-induced periodic surface structures, to improve cell adherence, alignment and proliferation on implants. The main differences in both the bioactivity in simulated body fluid and the biocompatibility in osteoblastic cell MC3T3 proliferation were measured and analyzed among Ti-6Al-4V samples with smooth surface, micro-hexagons and composite micro/nano-structures, respectively. Of note, bioinspired micro/nano-structures displayed the best bioactivity and biocompatibility after in vitro experiments, and meanwhile, the nano-ripples were able to induce cellular alignment within the micro-hexagons. The reasons for these differences were found in the topographical cues. An innovative functionalization strategy of controlling the osteointegration on titanium alloy implants is proposed using the composite micro/nano-structures, which is meaningful in various regenerative medicine applications and implant fields. Full article

(This article belongs to the Special Issue 25th Anniversary of Molecules—Recent Advances in Nanochemistry)

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Review

Jump to: Research

25 pages, 4251 KiB

Open AccessReview

Insights into the Structure and Energy of DNA Nanoassemblies

by Andreas Jaekel, Pascal Lill, Stephen Whitelam and Barbara Saccà

Molecules 2020, 25(23), 5466; https://doi.org/10.3390/molecules25235466 - 24 Nov 2020

Cited by 7 | Viewed by 4442

Abstract

Since the pioneering work of Ned Seeman in the early 1980s, the use of the DNA molecule as a construction material experienced a rapid growth and led to the establishment of a new field of science, nowadays called structural DNA nanotechnology. Here, the [...] Read more.

Since the pioneering work of Ned Seeman in the early 1980s, the use of the DNA molecule as a construction material experienced a rapid growth and led to the establishment of a new field of science, nowadays called structural DNA nanotechnology. Here, the self-recognition properties of DNA are employed to build micrometer-large molecular objects with nanometer-sized features, thus bridging the nano- to the microscopic world in a programmable fashion. Distinct design strategies and experimental procedures have been developed over the years, enabling the realization of extremely sophisticated structures with a level of control that approaches that of natural macromolecular assemblies. Nevertheless, our understanding of the building process, i.e., what defines the route that goes from the initial mixture of DNA strands to the final intertwined superstructure, is, in some cases, still limited. In this review, we describe the main structural and energetic features of DNA nanoconstructs, from the simple Holliday junction to more complicated DNA architectures, and present the theoretical frameworks that have been formulated until now to explain their self-assembly. Deeper insights into the underlying principles of DNA self-assembly may certainly help us to overcome current experimental challenges and foster the development of original strategies inspired to dissipative and evolutive assembly processes occurring in nature. Full article

(This article belongs to the Special Issue 25th Anniversary of Molecules—Recent Advances in Nanochemistry)

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41 pages, 9536 KiB

Open AccessReview

Covalent Organic Framework Composites: Synthesis and Analytical Applications

by Jenni J. Jarju, Ana M. Lavender, Begoña Espiña, Vanesa Romero and Laura M. Salonen

Molecules 2020, 25(22), 5404; https://doi.org/10.3390/molecules25225404 - 18 Nov 2020

Cited by 37 | Viewed by 9187

Abstract

In the recent years, composite materials containing covalent organic frameworks (COFs) have raised increasing interest for analytical applications. To date, various synthesis techniques have emerged that allow for the preparation of crystalline and porous COF composites with various materials. Herein, we summarize the [...] Read more.

In the recent years, composite materials containing covalent organic frameworks (COFs) have raised increasing interest for analytical applications. To date, various synthesis techniques have emerged that allow for the preparation of crystalline and porous COF composites with various materials. Herein, we summarize the most common methods used to gain access to crystalline COF composites with magnetic nanoparticles, other oxide materials, graphene and graphene oxide, and metal nanoparticles. Additionally, some examples of stainless steel, polymer, and metal-organic framework composites are presented. Thereafter, we discuss the use of these composites for chromatographic separation, environmental remediation, and sensing. Full article

(This article belongs to the Special Issue 25th Anniversary of Molecules—Recent Advances in Nanochemistry)

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23 pages, 2675 KiB

Open AccessFeature PaperReview

Recent Advances in Electrochemiluminescence and Chemiluminescence of Metal Nanoclusters

by Shuang Han, Yuhui Zhao, Zhichao Zhang and Guobao Xu

Molecules 2020, 25(21), 5208; https://doi.org/10.3390/molecules25215208 - 9 Nov 2020

Cited by 26 | Viewed by 5786

Abstract

Metal nanoclusters (NCs), including Au, Ag, Cu, Pt, Ni and alloy NCs, have become more and more popular sensor probes with good solubility, biocompatibility, size-dependent luminescence and catalysis. The development of electrochemiluminescent (ECL) and chemiluminescent (CL) analytical methods based on various metal NCs [...] Read more.

Metal nanoclusters (NCs), including Au, Ag, Cu, Pt, Ni and alloy NCs, have become more and more popular sensor probes with good solubility, biocompatibility, size-dependent luminescence and catalysis. The development of electrochemiluminescent (ECL) and chemiluminescent (CL) analytical methods based on various metal NCs have become research hotspots. To improve ECL and CL performances, many strategies are proposed, from metal core to ligand, from intermolecular electron transfer to intramolecular electron transfer. Combined with a variety of amplification technology, i.e., nanostructure-based enhancement and biological signal amplification, highly sensitive ECL and CL analytical methods are developed. We have summarized the research progresses since 2016. Also, we discuss the current challenges and perspectives on the development of this area. Full article

(This article belongs to the Special Issue 25th Anniversary of Molecules—Recent Advances in Nanochemistry)

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20 pages, 1564 KiB

Open AccessReview

Polymeric Nanoparticles: Production, Characterization, Toxicology and Ecotoxicology

by Aleksandra Zielińska, Filipa Carreiró, Ana M. Oliveira, Andreia Neves, Bárbara Pires, D. Nagasamy Venkatesh, Alessandra Durazzo, Massimo Lucarini, Piotr Eder, Amélia M. Silva, Antonello Santini and Eliana B. Souto

Molecules 2020, 25(16), 3731; https://doi.org/10.3390/molecules25163731 - 15 Aug 2020

Cited by 865 | Viewed by 35106

Abstract

Polymeric nanoparticles (NPs) are particles within the size range from 1 to 1000 nm and can be loaded with active compounds entrapped within or surface-adsorbed onto the polymeric core. The term “nanoparticle” stands for both nanocapsules and nanospheres, which are distinguished by the [...] Read more.

Polymeric nanoparticles (NPs) are particles within the size range from 1 to 1000 nm and can be loaded with active compounds entrapped within or surface-adsorbed onto the polymeric core. The term “nanoparticle” stands for both nanocapsules and nanospheres, which are distinguished by the morphological structure. Polymeric NPs have shown great potential for targeted delivery of drugs for the treatment of several diseases. In this review, we discuss the most commonly used methods for the production and characterization of polymeric NPs, the association efficiency of the active compound to the polymeric core, and the in vitro release mechanisms. As the safety of nanoparticles is a high priority, we also discuss the toxicology and ecotoxicology of nanoparticles to humans and to the environment. Full article

(This article belongs to the Special Issue 25th Anniversary of Molecules—Recent Advances in Nanochemistry)

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25 pages, 2481 KiB

Open AccessReview

Nanomaterials for Wound Dressings: An Up-to-Date Overview

by Alexandra Elena Stoica, Cristina Chircov and Alexandru Mihai Grumezescu

Molecules 2020, 25(11), 2699; https://doi.org/10.3390/molecules25112699 - 10 Jun 2020

Cited by 148 | Viewed by 11655

Abstract

As wound healing continues to be a challenge for the medical field, wound management has become an essential factor for healthcare systems. Nanotechnology is a domain that could provide different new approaches concerning regenerative medicine. It is worth mentioning the importance of nanoparticles, [...] Read more.

As wound healing continues to be a challenge for the medical field, wound management has become an essential factor for healthcare systems. Nanotechnology is a domain that could provide different new approaches concerning regenerative medicine. It is worth mentioning the importance of nanoparticles, which, when embedded in biomaterials, can induce specific properties that make them of interest in applications as materials for wound dressings. In the last years, nano research has taken steps to develop molecular engineering strategies for different self-assembling biocompatible nanoparticles. It is well-known that nanomaterials can improve burn treatment and also the delayed wound healing process. In this review, the first-line of bioactive nanomaterials-based dressing categories frequently applied in clinical practice, including semi-permeable films, semipermeable foam dressings, hydrogel dressings, hydrocolloid dressings, alginate dressings, non-adherent contact layer dressings, and multilayer dressings will be discussed. Additionally, this review will highlight the lack of high-quality evidence and the necessity for future advanced trials because current wound healing therapies generally fail to provide an excellent clinical outcome, either structurally or functionally. The use of nanomaterials in wound management represents a unique tool that can be specifically designed to closely reflect the underlying physiological processes in tissue repair. Full article

(This article belongs to the Special Issue 25th Anniversary of Molecules—Recent Advances in Nanochemistry)

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