MXene-Based Nanocomposites for Piezoelectric and Triboelectric Energy Harvesting Applications.

Due to its superior advantages in terms of electronegativity, metallic conductivity, mechanical flexibility, customizable surface chemistry, etc., 2D MXenes for nanogenerators have demonstrated significant progress. In order to push scientific design strategies for the practical application of nanogenerators from the viewpoints of the basic aspect and recent advancements, this systematic review covers the most recent developments of MXenes for nanogenerators in its first section. In the second section, the importance of renewable energy and an introduction to nanogenerators, major classifications, and their working principles are discussed. At the end of this section, various materials used for energy harvesting and frequent combos of MXene with other active materials are described in detail together with the essential framework of nanogenerators. In the third, fourth, and fifth sections, the materials used for nanogenerators, MXene synthesis along with its properties, and MXene nanocomposites with polymeric materials are discussed in detail with the recent progress and challenges for their use in nanogenerator applications. In the sixth section, a thorough discussion of the design strategies and internal improvement mechanisms of MXenes and the composite materials for nanogenerators with 3D printing technologies are presented. Finally, we summarize the key points discussed throughout this review and discuss some thoughts on potential approaches for nanocomposite materials based on MXenes that could be used in nanogenerators for better performance.

ZnO/Graphene Composite from Solvent-Exfoliated Few-Layer Graphene Nanosheets for Photocatalytic Dye Degradation under Sunlight Irradiation.

ZnO/graphene nanocomposites were prepared using a facile approach. Graphene nanosheets were prepared by ultrasonication-based liquid phase exfoliation of graphite powder in a low boiling point organic solvent, 1,2-Dichloroethane, for the preparation of ZnO/graphene nanocomposites. Structural properties of the synthesized ZnO/graphene nanocomposites were studied through powder XRD and micro-Raman analysis. The characteristic Raman active modes of ZnO and graphene present in the micro-Raman spectra ensured the formation of ZnO/graphene nanocomposite and it is inferred that the graphene sheets in the composites were few layers in nature. Increasing the concentration of graphene influenced the surface morphology of the ZnO nanoparticles and a flower shape ZnO was formed on the graphene nanosheets of the composite with high graphene concentration. The efficiencies of the samples for the photocatalytic degradation of Methylene Blue dye under sunlight irradiation were investigated and 97% degradation efficiency was observed. The stability of the nanocomposites was evaluated by performing five cycles, and 92% degradation efficiency was maintained. The observed results were compared with that of ZnO/graphene composite derived from other methods.

MXene/Ferrite Magnetic Nanocomposites for Electrochemical Supercapacitor Applications.

MXene has been identified as a new emerging material for various applications including energy storage, electronics, and bio-related due to its wider physicochemical characteristics. Further the formation of hybrid composites of MXene with other materials makes them interesting to utilize in multifunctional applications. The selection of magnetic nanomaterials for the formation of nanocomposite with MXene would be interesting for the utilization of magnetic characteristics along with MXene. However, the selection of the magnetic nanomaterials is important, as the magnetic characteristics of the ferrites vary with the stoichiometric composition of metal ions, particle shape and size. The selection of the electrolyte is also important for electrochemical energy storage applications, as the electrolyte could influence the electrochemical performance. Further, the external magnetic field also could influence the electrochemical performance. This review briefly discusses the synthesis method of MXene, and ferrite magnetic nanoparticles and their composite formation. We also discussed the recent progress made on the MXene/ferrite nanocomposite for potential applications in electrochemical supercapacitor applications. The possibility of magnetic field-assisted supercapacitor applications with electrolyte and electrode materials are discussed.

Laser induced Fano scattering, electron-phonon coupling, bond length and phonon lifetime changes in α-Fe2O3 nanostructures.

We have extensively studied the laser-induced Fano scattering, electron-phonon coupling, bond length and phonon lifetime of the α-Fe2O3 nanostructure prepared through a simple co-precipitation method. A noticeable red shift and asymmetry have been observed in the phonon modes of the prepared α-Fe2O3 nanostructure. The traditional assessment of asymmetric broadening and a red shift in the Raman spectra of a nanomaterial was due to the quantum confinement effect. In the present investigation, the red shift and the asymmetry in the phonon modes of the α-Fe2O3 nanostructure have been studied on the basis of the heating effect and Fano interference between the discrete phonon and the laser-induced electron plasma in the nanomaterial. The observed asymmetrical factors of the A1g(1) and Eg(4) phonon modes were positive and negative respectively and are seen to be decreasing with the laser power. The laser-induced surface temperature of the material has been studied using the Stokes/anti-Stokes method. The bond lengths of the Fe-O molecules present in the α-Fe2O3 nanomaterial increased and the calculated Fröhlich interactions decreased with the laser energy.

Molecular investigation to RNA and protein based interaction induced in vivo biocompatibility of phytofabricated AuNP with embryonic zebrafish.

Implication of gold nanoparticles in industrial and day-to-day life products at extensive scale has raised concern about their toxicity to environment and human health. Moreover, quest of new technologies for production of biocompatible nanoparticles increased. This study explores the molecular toxicology of AuNP with enlightenment of their green synthesis using medicinal plant extract as reducing and stabilizing agent. Synthesized CAuNP were characterized for their physiochemical properties by standard techniques like FESEM, TEM, DLS, UV-Vis spectroscopy and FTIR. GCMS analysis revealed the involvement of -OH compounds for CAuNP synthesis. Determined size and zeta potential of CAuNP was found to be 21 ± 08 nm and -24 ± 11 mV with SPR peak at 554 nm. LC50 of CAuNP with zebrafish embryos was 69 ± 12 µg/ml compared to 52 ± 06 µg/ml of AuNP. Gold nanoparticles were found to exhibit concentration dependent morphological abnormalities with acute effect at cellular and molecular level. Experimental and computational analysis depicted the nanotoxicity of gold nanoparticles as a consequence of oxidative stress generation leading to apoptosis due to their influential interaction with Sod1, He1a and tp53 mRNA and proteins. The investigation deciphered the nanotoxicity of gold nanoparticles and suggested the implication of new green methodology for their future productions.

Drug-in-mucoadhesive type film for ocular anti-inflammatory potential of amlodipine: Effect of sulphobutyl-ether-beta-cyclodextrin on permeation and molecular docking characterization.

Mucoadhesive type ocular film has been prepared for studying the anti-inflammatory potential of amlodipine (AML) on carrageenan-induced rabbit model and the effect of sulphobutyl-ether-beta-cyclodextrin on corneal permeation was tested. Hydroxypropyl methylcellulose (HPMC) ocular film was prepared after complexation of amlodipine with ß-cyclodextrin, (BCD), hydroxypropyl ß-cyclodextrin (HPCD), and sulfobutylether ß-cyclodextrin (SBCD). The film without cyclodextrin showed a maximum swelling, and erosion to the highest extent. Both drug release and permeation were highly diffusion controlled and highest improvement was observed with SBCD due to increased dissolution, compared to other formulations with or without cyclodextrin. Highest binding energy and highest extent of amorphization were noticed in the SBCD film formulation. Improved amlodipine release in-vitro and ocular permeation were found by the HPMC film formulation after complexation of the drug with cyclodextrins wherein SBCD exhibited both to the highest extent. Binary and ternary systems molecular docking studies confirmed the lowest energy of binding between amlodipine and BCD compared to HBCD and SBCD. Signs of acute inflammation were mitigated within 2 h of film application in the cul-de-sac. Presence of sulphobutyl-ether ß-cyclodextrin in the amlodipine-HPMC film can improve ocular permeation significantly and could be utilized as mucoadhesive type formulation for anti-inflammatory activity.

Molecular insights to alkaline based bio-fabrication of silver nanoparticles for inverse cytotoxicity and enhanced antibacterial activity.

High demand for silver nanoparticles due to their extensive applications in different field has raised need of eco-friendly green synthesis with determined biomedical effects. This study proposes a novel rapid controlled alkaline based green synthesis of antibacterial silver nanoparticles from Calotropis gigantea for reduced cytotoxic effects. Silver nanoparticles termed as FAg, FAg1N, and FAg5N were synthesized with the help of floral extract of Calotropis gigantea as reducing and capping agent in presence of UV light and NaOH for catalysis and were characterized for their physiochemical properties by FESEM, DLS, UV-Visible spectrophotometry and FTIR. Facile synthesized Silver nanoparticles FAg1N and FAg5N showed enhanced antibacterial effects than FAg with increased NaOH concentration. Cytotoxic effect was found to be reduced at optimized alkaline conditioned FAg1N than FAg and FAg5N. Molecular dynamics study depicted the significant role of configurational change in "Calotropin" at variable alkalinity for controlling the size and physiological properties of synthesized AgNPs. The mechanism of cytotoxicity was revealed as consequences of variability in the interaction of Sod1 and P53 proteins with AgNPs surface for oxidative stress induction and programmed cell death.

Mechanistic insight into ROS and neutral lipid alteration induced toxicity in the human model with fins (Danio rerio) by industrially synthesized titanium dioxide nanoparticles.

The toxicological impact of TiO2 nanoparticles on the environment and human health has been extensively studied in the last few decades, but the mechanistic details were unknown. In this study, we evaluated the impact of industrially prepared TiO2 nanoparticles on the biological system using zebrafish embryo as an in vivo model. The industrial synthesis of TiO2 nanoparticles was mimicked on the lab scale using the high energy ball milling (HEBM) method by milling bulk TiO2 particles for 5 h, 10 h, and 15 h in an ambient environment. The physiochemical properties were characterized by standard methods like field emission scanning electron microscopy (FESEM), dynamic light scattering (DLS), X-ray diffraction (XRD) and UV-Visible spectroscopy. In vivo cytotoxicity was assessed on zebrafish embryos by the evaluation of their mortality rate and hatching rate. Experimental and computational analysis of reactive oxygen species (ROS) induction, apoptosis, and neutral lipid alteration was done to study the effects on the cellular level of zebrafish larvae. The analysis depicted the change in size and surface charge of TiO2 nanoparticles with respect to the increase in milling time. In silico investigations revealed the significant role of ROS quenching and altered neutral lipid accumulation functionalised by the molecular interaction of respective metabolic proteins in the cytotoxicity of TiO2 nanoparticles with zebrafish embryos. The results reveal the hidden effect of industrially synthesized TiO2 nanoparticle exposure on the alteration of lipid accumulation and ROS in developing zebrafish embryos. Moreover, the assessment provided a detailed mechanistic analysis of in vivo cytotoxicity at the molecular level.

Mechanistic Insight into Size-Dependent Enhanced Cytotoxicity of Industrial Antibacterial Titanium Oxide Nanoparticles on Colon Cells Because of Reactive Oxygen Species Quenching and Neutral Lipid Alteration.

This study evaluates the impact of industrially prepared TiO2 nanoparticles on the biological system by using an in vitro model of colon cancer cell lines (HCT116). Industrial synthesis of titanium oxide nanoparticles was mimicked on the lab scale by the high-energy ball milling method by milling bulk titanium oxide particles for 5, 10, and 15 h in an ambient environment. The physiochemical characterization by field emission scanning electron microscopy, dynamic light scattering, and UV-visible spectroscopy revealed alteration in the size and surface charge with respect to increase in the milling time. The size was found to be reduced to 82 ± 14, 66 ± 12, and 42 ± 10 nm in 5, 10, and 15 h milled nano TiO2 from 105 ± 12 nm of bulk TiO2, whereas the zeta potential increased along with the milling time in all biological media. Cytotoxicity and genotoxicity assays performed with HCT116 cell lines by MTT assay, oxidative stress, intracellular lipid analysis, apoptosis, and cell cycle estimation depicted cytotoxicity as a consequence of reactive oxygen species quenching and lipid accumulation, inducing significant apoptosis and genotoxic cytotoxicity. In silico analysis depicted the role of Sod1, Sod2, p53, and VLDR proteins-TiO2 hydrogen bond interaction having a key role in determining the cytotoxicity. The particles exhibited significant antibacterial activities against Escherichia coli and Salmonella typhimurium.

Molecular aspects of core-shell intrinsic defect induced enhanced antibacterial activity of ZnO nanocrystals.

AIM: To investigate molecular aspects of the antibacterial effect of size-dependent core-shell intrinsic defects of nanocrystalline ZnO synthesized through high energy ball milling technique. MATERIALS & METHODS: Mechanically synthesized and characterized 7, 10 and 15 h milled ZnO nanoparticles were evaluated for antibacterial activity with molecular investigation by computational molecular docking. RESULTS: Synthesized ZnO nanoparticles displayed shrinkage of core and increase of shell with reduction in size of bulk ZnO particles from 250 to 80, 40 and 20 nm and increase in zeta potential up to -19 mV in 7, 10 and 15 h nano ZnO. Antibacterial activity was found increased with decrease in size due to increased reactive oxygen species and membrane damage in bacteria. CONCLUSION: Synthesized nano ZnO exhibit size-dependent antibacterial action as consequences of interactions with cell membrane proteins via hydrogen bond interaction with amino acid residues followed by internalization, membrane depolarization and induction of reactive oxygen species generation.

Rapid Novel Facile Biosynthesized Silver Nanoparticles From Bacterial Release Induce Biogenicity and Concentration Dependent In Vivo Cytotoxicity With Embryonic Zebrafish-A Mechanistic Insight.

In this study, rapid one step facile synthesis of silver nanoparticles (AgNPs) was done using culture supernatant of two Gram positive (B. thuringiensis and S. aureus) and Gram negative (E. coli and Salmonella typhimurium [STAgNP]) bacterial strains and were termed as "Bacillus thuringiensis," "Staphylococcus aureus," "Escherichia coli," and "STAgNP," respectively. Synthesized AgNPs were well characterized with the help of different standard techniques like FESEM, DLS, UV-Vis spectroscopy, and Fourier transform infrared. Mechanism of AgNPs synthesis was elucidated using in silico approach. In vivo cytotoxicity of synthesized AgNPs was assessed in embryonic Zebrafish model with the help of uptake, oxidative stress, and apoptosis induction experimental assays, and the mechanism was investigated through in silico approach at the molecular level. The result showed successful biosynthesis of 20-40 nm sized AgNPs stable with zeta potential of - 45 to - 35 mV having standard silver nanoparticles SPR peaks due to the interaction of reduced silver particles with amino acid residues of bapA proteins of the bacterial supernatant. In vivo cytotoxicity with embryonic Zebrafish was found to be dependent on biogenicity and concentration of biosynthesized AgNPs as consequence of oxidative stress induction and apoptosis due to the influential regulation of sod1 and tp53 genes clarified by pathway analysis with reference to experimental and computational results. The study suggested that cytotoxicity of biologically synthesized silver nanoparticles from bacteria depends on strain specificity with significant difference in use of Gram positive and Gram negative bacterial strains.

CdS QDs-Decorated Self-Doped γ-Bi2MoO6: A Sustainable and Versatile Photocatalyst toward Photoreduction of Cr(VI) and Degradation of Phenol.

In this work, CdS quantum dots (QDs)-sensitized self-doped Bi2MoO6 has been synthesized using glucose as reducing agent by hydrothermal method, followed by in situ deposition of the QDs. The synthesized catalyst has been employed to reduce toxic Cr(VI) and degrade phenol from the aqueous solution. The structural, optical, and electrochemical characterizations are performed using X-ray diffraction, UV-vis diffuse reflection, photoluminescence (PL), scanning electron microscopy, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy, and electrochemical impedance spectroscopy. The optical properties were precisely investigated by calculating the Urbach energy, PL, and photoluminescence excitation spectra. The orderly distribution of QDs is confirmed from the correlation between full width at half-maximum of PL spectra, Urbach energy, and TEM analysis. The versatile photocatalytic activity has been tested toward Cr(VI) reduction and degradation of phenol. 3% CdS QDs-sensitized self-doped Bi2MoO6 showed highest activity, i.e., 97 and 47.5% toward reduction of Cr(VI) and degradation of phenol under solar light. The reduction of Cr(VI) by the catalyst is supported by the kinetics and determination of the pHPZC value. In addition to this, the photostability and reusability test showed that the catalyst can be reused up to five cycles without diminishing its activity.

Amorphous MoSx thin-film-coated carbon fiber paper as a 3D electrode for long cycle life symmetric supercapacitors.

Amorphous MoSx thin-film-coated carbon fiber paper as a binder-free 3D electrode was synthesized by a facile hydrothermal method. The maximum specific capacitance of a single electrode was 83.9 mF cm(-2), while it was 41.9 mF cm(-2) for the symmetric device. Up to 600% capacitance retention was observed for 4750 cycles.

Synthesis and magnetic properties of flower-like FeCo particles through a one pot polyol process.

FeCo alloys of various compositions with flower-like morphology were synthesized using a unique one pot polyol process. The morphology of Fe particles was cubic, whereas the FeCo particles showed flower-like morphology, with more petals for the Co rich FeCo. The average particle size varied from 120 to 155 nm depending on the composition of the alloy. The Curie temperature as determined by thermomagnetic analysis was 985°C for Fe67Co33 and 939°C for the Fe36Co64 samples. Their corresponding bcc to fcc phase transformation temperatures were 985 and 825°C, respectively. Coercivity up to 511Oe was observed due to the shape anisotropy arising out of the flower-like morphology compared to the usual cubic or spherical morphologies. Post-annealing studies showed that Fe67Co33 is more stable compared to other compositions.