A superabsorbent and pH-responsive copolymer-hydrogel based on acemannan from Aloe vera (Aloe barbadensis M.): A smart material for drug delivery.

Combining natural polysaccharides with synthetic materials improves their functional properties which are essential for designing sustained-release drug delivery systems. In this context, the Aloe vera leaf mucilage/hydrogel (ALH) was reacted with acrylic acid (AA) to synthesize a copolymerized hydrogel, i.e., ALH-grafted-Polyacrylic acid (ALH-g-PAA) through free radical copolymerization. Concentrations of the crosslinker N,N'-methylene-bis-acrylamide (MBA), and the initiator potassium persulfate (KPS) were optimized to study their effects on ALH-g-PAA swelling. The FTIR and solid-state NMR (CP/MAS 13C NMR) spectra witnessed the formation of ALH-g-PAA. Scanning electron microscopy (SEM) analysis revealed superporous nature of ALH-g-PAA. The gel fraction (%) of ALH-g-PAA was directly related to the concentrations of AA and MBA whereas the sol fraction was inversely related to the concentrations of AA and MBA. The porosity (%) of ALH-g-PAA directly depends on the concentration of AA and MBA. The ALH-g-PAA swelled admirably at pH 7.4 and insignificantly at pH 1.2. The ALH-g-PAA offered on/off switching properties at pH 7.4/1.2. The metoprolol tartrate was loaded on different formulations of ALH-g-PAA. The ALH-g-PAA showed pH, time, and swelling-dependent release of metoprolol tartrate (MT) for 24 h following the first-order kinetic and Korsmeyer-Peppas model. Haemocompatibility studies ascertained the non-thrombogenic and non-hemolytic behavior of ALH-g-PAA.

Citric acid cross-linking of a hydrogel from Aloe vera (Aloe barbadensis M.) engenders a pH-responsive, superporous, and smart material for drug delivery.

The current research work is based on the evaluation of a citric acid (CA) cross-linked Aloe vera (Aloe barbadensis M.) leaf hydrogel (CL-ALH) for pH-dependent and sustained drug release application. The CA was used in different concentrations (1.25, 2.5, 5.0, and 10.0%) to cross-link the ALH using homogenous reaction conditions. The synthesis of CL-ALH was confirmed through Fourier transform and nuclear magnetic resonance spectroscopic studies. The thermal analysis indicated that the ALH and CL-ALH were stable and decomposed in two steps. The scanning electron microscopic images of CL-ALH confirmed its porous nature due to the presence of interconnected channeling. The swelling of CL-ALH was evaluated at pH 1.2, 6.8, and 7.4 as well as in deionized water (DW). High swelling of CL-ALH was observed in DW, and at pH 7.4 and 6.8 whereas, less swelling of CL-ALH was witnessed at pH 1.2. CL-ALH also exhibited swelling/deswelling behavior in DW and ethanol, DW and normal saline, and at pH 7.4 and 1.2. Tablets were prepared from CL-ALH as a release retarding agent demonstrating the sustained release of venlafaxine hydrochloride (VFX) for 8 h. Whereas, VFX was released within 4 h from the ALH-based tablet formulation (un-cross-linked material) indicating the prolonged and sustained release behavior of CL-ALH. The VFX was released from CL-ALH tablets and followed zero-order kinetics. The mechanism followed by VFX release from CL-ALH tablets was non-Fickian diffusion. The in vivo fate of the tablet formulation was observed through an X-ray study. The CL-ALH-based tablet safely passed through the stomach of a stray dog without any significant erosion and then disintegrated in the small intestine and colon. These findings confirmed that the CL-ALH is an effective excipient for designing a sustained-release drug delivery system for the small intestine and colon.

Chemical modification of Aloe vera leaf hydrogel for efficient cadmium-removal from spiked high-hardness groundwater.

Herein, the hydrogel from the leaf of the Aloe vera plant (ALH) was succinylated (SALH) and saponified (NaSALH). The FTIR, solid-state CP/MAS 13C NMR, and SEM-EDX spectroscopic analyses witnessed the formation of SALH and NaSALH from ALH. The pHZPC for NaSALH was found to be 4.90, indicating the presence of -ve charge on its surface. The Cd2+ sorption efficiency of NaSALH was found to be dependent on pH, NaALH dose, Cd2+ concentration, contact time, and temperature. The maximum Cd2+ removal from DW and HGW was found to be 227.27 and 212.77 mg g-1 according to the Langmuir isothermal model (>0.99) at pH of 6, NaSALH dose of 40 mg g-1, Cd2+ concentration of 90 mg L-1, contact time of 30 min, and temperature of 298 K. The kinetic analysis of Cd2+ sorption data witnessed that the Cd2+ removal by chemisorption mechanism and followed pseudo-second-order kinetics (>0.99). The -ve values of ΔG° and ΔH° assessed the spontaneous and exothermic nature of sorption of Cd2+ by NaSALH. The regeneration and sorption/desorption studies indicated that the sorbent NaSALH is regenerable.

Surfactin-Conjugated Silver Nanoparticles as an Antibacterial and Antibiofilm Agent against Pseudomonas aeruginosa.

The emergence of antimicrobial resistance is an alarming global health concern and has stimulated the development of novel functional nanomaterials to combat multi-drug-resistant (MDR) bacteria. In this work, we demonstrate for the first time the synthesis and application of surfactin-coated silver nanoparticles as an efficient antibacterial and antibiofilm agent against the drug-resistant bacteria Pseudomonas aeruginosa for safe dermal applications. Our in vivo studies showed no significant superficial dermal irritation, edema, and erythema, while microscopic analysis revealed that surfactin-coated silver nanoparticles caused no pathological alterations at the applied concentrations. These results support the potential use of surfactin-coated silver nanoparticles against drug-resistant bacterial biofilm infections and in skin wound dressing applications.

Synthesis and Photophysical, Electrochemical, and DFT Studies of Piperidyl and Pyrrolidinyl Chalcones.

Small organic molecules with interesting optical and electrochemical properties find applications as organic luminescent materials. In this work, we report the synthesis of novel chalcones with D-A-D and D-A-D-A architecture, followed by their optical, electrochemical, and computational studies. The absorption band of these compounds occurs at 360-480 nm with emission maxima appearing around 513-552 nm. The large Stokes shifts (Δλ) for all compounds (90-132 nm) suggest intramolecular charge transfer (ICT) in the excited states. The molar absorptivity and fluorescence quantum yields were found to be in the range of 1.7-4.26 × 104 M-1 cm-1 and 0.29-0.39, respectively. The electrochemical parameters were determined by using cyclic voltammetry (CV). Density functional theory (DFT) calculations of all compounds were made by using B3LYP/G (d,p) functionals in chloroform and were found to have a good correlation with experimental results. Preliminary studies of absorption, photoluminescence, CV, and their theoretical correlation suggest that these compounds may be optimized for their applications in optoelectronics, sensing, and bioimaging.

Characterization of plastic degrading bacteria isolated from sewage wastewater.

Plastic is a fundamental polymer used in routine life and disposed of in sewage. It leads to microplastic pollution in aquatic organisms, introducing it into the food chain and affecting human health. In the present study, samples were collected from sewage wastewater to isolate the bacteria that could potentially reduce plastic. The six samples were incubated with plastic pieces in minimal salt media for 120 days. After 120 days, the weight loss experiment showed that samples SH5B and SH6B degraded 25% plastic. After chemical and molecular characterization, these strains were identified as Pseudomonas sp. SH5B and Pseudomonas aeruginosa SH6B. The Fourier-transform infrared spectroscopy (FTIR) analysis showed peaks shifting, indicating bond stretching, bond bending, and new bond formation. The Gas Chromatography-Mass Spectrometry (GC-MS) analysis revealed various new compounds produced during plastic degradation by these bacterial strains. The plastic biodegradation potential makes these bacteria an impending foundation for green chemistry to eradicate tough pollutants from the environment.

Impact of alternate Mn doping in ternary nanocomposites on their structural, optical and antimicrobial properties: Comparative analysis of photocatalytic degradation and antibacterial activity.

The present study was done to investigate and compare the photocatalytic and antibacterial activity of two in situ Manganese doped ternary nanocomposites. The dual ternary hybrid systems comprised Mn-doped Ag2WO4 coupled with MoS2-GO and Mn-doped MoS2 coupled with Ag2WO4-GO. Both hierarchical alternate Mn-doped ternary heterojunctions formed efficient plasmonic catalysts for wastewater treatment. The novel nanocomposites were well-characterized using XRD, FTIR, SEM-EDS, HR-TEM, XPS, UV-VIS DRS, and PL techniques confirming the successful insertion of Mn+2 ions in respective host substrates. The bandgap of the ternary nanocomposites evaluated by the tauc plot showed them visible light-active nanocomposites. The photocatalytic ability of both Mn-doped coupled nanocomposites was investigated against the dye methylene blue. Both ternary nanocomposites showed excellent sunlight harvesting ability for dye degradation in 60 min. The maximum catalytic efficiency of both photocatalysts was obtained at a solution pH value of 8, photocatalyst dose and oxidant dose of 30 mg/100 mL and 1 mM for Mn-Ag2WO4/MoS2-GO, 50 mg/100 mL, 3 mM for Mn-MoS2/Ag2WO4-GO keeping IDC of 10 ppm for all photocatalysts. The nanocomposites showed excellent photocatalytic stability after five successive cycles. The response surface methodology was used as a statistical tool for the evaluation of the photocatalytic response of several interacting parameters for dye degradation by ternary composites. The antibacterial activity was determined by the inactivation of gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacteria by support-based doped ternary hybrids.

A pH responsive and superporous biocomposite hydrogel of Salvia spinosa polysaccharide-co-methacrylic acid for intelligent drug delivery.

Herein, a drug delivery system (SSH-co-MAA) based on the mucilage from seeds of Salvia spinosa (SSH; polymer) and methacrylic acid (MAA; monomer) is introduced for the controlled delivery of venlafaxine HCl using a sustainable chemical approach. The optimized conditions for the designing of the ideal formulation (M4) of SSH-co-MAA were found to be 2.5% (w/w) of SSH, 30.0% (w/w) of MAA, 0.4% (w/w) of both N,N'-methylene-bis-acrylamide (MBA; cross-linker) and potassium persulfate (KPS; initiator). The structure characterization of SSH-co-MAA by Fourier transform infrared and solid-state CP/MAS 13C-NMR spectroscopy has confirmed the grafting of MAA onto SSH. The thermogravimetric analysis revealed that SSH-co-MAA is a stable entity before and after loading of the venlafaxine HCl-loaded SSH-co-MAA (VSSH-co-MAA). Scanning electron microscopy images of SSH-co-MAA after swelling then freeze drying showed the superporous nature of the hydrogel. The gel fraction (%) of SSH-co-MAA depended upon concentration of SSH, MAA, and MBA. The porosity (%) was increased with the increase in the concentration of SSH and decreased with the decrease in the concentration of MAA and MBA. The swelling indices, venlafaxine HCl loading, and release (24 h at the pH of the gastrointestinal tract) from VSSH-co-MAA were found to be dependent on the pH of the swelling media and the concentration of SSH, MAA, and MBA. The release of venlafaxine HCl followed non-Fickian diffusion mechanism. Conclusively, SSH-co-MAA is a novel material for potential application in targeted drug delivery applications.

Natural Products/Bioactive Compounds as a Source of Anticancer Drugs.

Cancer is one of the major deadly diseases globally. The alarming rise in the mortality rate due to this disease attracks attention towards discovering potent anticancer agents to overcome its mortality rate. The discovery of novel and effective anticancer agents from natural sources has been the main point of interest in pharmaceutical research because of attractive natural therapeutic agents with an immense chemical diversity in species of animals, plants, and microorganisms. More than 60% of contemporary anticancer drugs, in one form or another, have originated from natural sources. Plants and microbial species are chosen based on their composition, ecology, phytochemical, and ethnopharmacological properties. Plants and their derivatives have played a significant role in producing effective anticancer agents. Some plant derivatives include vincristine, vinblastine, irinotecan, topotecan, etoposide, podophyllotoxin, and paclitaxel. Based on their particular activity, a number of other plant-derived bioactive compounds are in the clinical development phase against cancer, such as gimatecan, elomotecan, etc. Additionally, the conjugation of natural compounds with anti-cancerous drugs, or some polymeric carriers particularly targeted to epitopes on the site of interest to tumors, can generate effective targeted treatment therapies. Cognizance from such pharmaceutical research studies would yield alternative drug development strategies through natural sources which could be economical, more reliable, and safe to use.

Natural Strategies as Potential Weapons against Bacterial Biofilms.

Microbial biofilm is an aggregation of microbial species that are either attached to surfaces or organized into an extracellular matrix. Microbes in the form of biofilms are highly resistant to several antimicrobials compared to planktonic microbial cells. Their resistance developing ability is one of the major root causes of antibiotic resistance in health sectors. Therefore, effective antibiofilm compounds are required to treat biofilm-associated health issues. The awareness of biofilm properties, formation, and resistance mechanisms facilitate researchers to design and develop combating strategies. This review highlights biofilm formation, composition, major stability parameters, resistance mechanisms, pathogenicity, combating strategies, and effective biofilm-controlling compounds. The naturally derived products, particularly plants, have demonstrated significant medicinal properties, producing them a practical approach for controlling biofilm-producing microbes. Despite providing effective antibiofilm activities, the plant-derived antimicrobial compounds may face the limitations of less bioavailability and low concentration of bioactive molecules. The microbes-derived and the phytonanotechnology-based antibiofilm compounds are emerging as an effective approach to inhibit and eliminate the biofilm-producing microbes.

Designing Synergistic Biostimulants Formulation Containing Autochthonous Phosphate-Solubilizing Bacteria for Sustainable Wheat Production.

Applying phosphate-solubilizing bacteria (PSB) as biofertilizers has enormous potential for sustainable agriculture. Despite this, there is still a lack of information regarding the expression of key genes related to phosphate-solubilization (PS) and efficient formulation strategies. In this study, we investigated rock PS by Ochrobactrum sp. SSR (DSM 109610) by relating it to bacterial gene expression and searching for an efficient formulation. The quantitative PCR (qPCR) primers were designed for PS marker genes glucose dehydrogenase (gcd), pyrroloquinoline quinone biosynthesis protein C (pqqC), and phosphatase (pho). The SSR-inoculated soil supplemented with rock phosphate (RP) showed a 6-fold higher expression of pqqC and pho compared to inoculated soil without RP. Additionally, an increase in plant phosphorous (P) (2%), available soil P (4.7%), and alkaline phosphatase (6%) activity was observed in PSB-inoculated plants supplemented with RP. The root architecture improved by SSR, with higher root length, diameter, and volume. Ochrobactrum sp. SSR was further used to design bioformulations with two well-characterized PS, Enterobacter spp. DSM 109592 and DSM 109593, using the four organic amendments, biochar, compost, filter mud (FM), and humic acid. All four carrier materials maintained adequate survival and inoculum shelf life of the bacterium, as indicated by the field emission scanning electron microscopy analysis. The FM-based bioformulation was most efficacious and enhanced not only wheat grain yield (4-9%) but also seed P (9%). Moreover, FM-based bioformulation enhanced soil available P (8.5-11%) and phosphatase activity (4-5%). Positive correlations were observed between the PSB solubilization in the presence of different insoluble P sources, and soil available P, soil phosphatase activity, seed P content, and grain yield of the field grown inoculated wheat variety Faisalabad-2008, when di-ammonium phosphate fertilizer application was reduced by 20%. This study reports for the first time the marker gene expression of an inoculated PSB strain and provides a valuable groundwork to design field scale formulations that can maintain inoculum dynamics and increase its shelf life. This may constitute a step-change in the sustainable cultivation of wheat under the P-deficient soil conditions.

Metal Complexation of Arabinoxylan Engenders a Smart Material Offering pH, Solvents, and Salt Responsive On-Off Swelling with the Potential for Sustained Drug Delivery.

The present study aimed to develop a stable interconnected matrix as a sustained release drug delivery material. Arabinoxylan (AX) was extracted from ispaghula husk and then crosslinked with different concentrations, i.e., 0.5, 1.0, and 1.5 g of CaCl2 per 0.25 g of AX. The crosslinking was confirmed through Fourier transform infrared spectroscopy. The swelling capacity of crosslinked AX (CL-AX) was evaluated against buffer solutions of pH 1.2, 6.8, 7.4, and water. The swelling capacity increased from pH 1.2 to pH 7.4 and followed the second order swelling kinetics. The swelling study also revealed that CL-AX with 1.0 g CaCl2 showed maximum swelling capacity. The swelling-deswelling (on-off switching) behavior of CL-AX was evaluated in water-ethanol, water-0.9% NaCl solution, and buffer solutions of pH 7.4-1.2 and showed responsive swelling-deswelling behavior. Scanning electron microscopy revealed a highly porous nature of CL-AX with a mesh of thin fibrous networking. Hemocompatibility studies of CL-AX revealed its non-thrombogenic and nonhemolytic attributes. The CL-AX matrix tablet prolonged the release of enalapril maleate for 24 h, and the drug release followed the zero order kinetics and super case-II transport mechanism. Therefore, CL-AX can be recognized as a stimuli responsive and hemocompatible biomaterial with sustained drug release potential.

Development and Mechanistic Studies of Ternary Nanocomposites for Hydrogen Production from Water Splitting to Yield Sustainable/Green Energy and Environmental Remediation.

Photocatalysts lead vitally to water purifications and decarbonise environment each by wastewater treatment and hydrogen (H2) production as a renewable energy source from water-photolysis. This work deals with the photocatalytic degradation of ciprofloxacin (CIP) and H2 production by novel silver-nanoparticle (AgNPs) based ternary-nanocomposites of thiolated reduce-graphene oxide graphitic carbon nitride (AgNPs-S-rGO2%@g-C3N4) material. Herein, the optimised balanced ratio of thiolated reduce-graphene oxide in prepared ternary-nanocomposites played matchlessly to enhance activity by increasing the charge carriers' movements via slowing down charge-recombination ratios. Reduced graphene oxide (rGO), >2 wt.% or <2 wt.%, rendered H2 production by light-shielding effect. As a result, CIP degradation was enhanced to 95.90% by AgNPs-S-rGO2%@g-C3N4 under the optimised pH(6) and catalyst dosage(25 mg/L) irradiating beneath visible-light (450 nm, 150 watts) for 70 min. The chemical and morphological analysis of AgNPs-S-rGO2%@g-C3N4 surface also supported the possible role of thiolation for this enhancement, assisted by surface plasmon resonance of AgNPs having size < 10 nm. Therefore, AgNPs-S-rGO2%@g-C3N4 has 3772.5 µmolg−1 h−1 H2 production, which is 6.43-fold higher than g-C3N4 having cyclic stability of 96% even after four consecutive cycles. The proposed mechanism for AgNPs-S-rGO2%@g-C3N4 revealed that the photo-excited electrons in the conduction-band of g-C3N4 react with the adhered water moieties to generate H2.

Microemulsified Gel Formulations for Topical Delivery of Clotrimazole: Structural and In Vitro Evaluation.

Microemulsified gels (µEGs) with fascinating functions have become indispensable as topical drug delivery systems due to their structural flexibility, high stability, and facile manufacturing process. Topical administration is an attractive alternative to traditional methods because of advantages such as noninvasive administration, bypassing first-pass metabolism, and improving patient compliance. In this article, we report on the new formulations of microemulsion-based gels suitable for topical pharmaceutical applications using biocompatible and ecological ingredients. For this, two biocompatible µE formulations comprising clove oil/Brij-35/water/ethanol (formulation A) and clove oil/Brij-35/water/1-propanol (formulation B) were developed to encapsulate and improve the load of an antimycotic drug, Clotrimazole (CTZ), and further gelatinized to control the release of CTZ through skin barriers. By delimiting the pseudo-ternary phase diagram, optimum µE formulations with clove oil (∼15%) and Brij-35 (∼30%) were developed, keeping constant surfactant/co-surfactant ratio (1:1), to upheld 2.0 wt % CTZ. The as-developed formulations were further converted into smart gels by adding 2.0 wt % carboxymethyl cellulose (CMC) as a cross-linker to adhere to the controlled release of CTZ through complex skin barriers. Electron micrographs show a fine, monodispersed collection of CTZ-µE nanodroplets (∼60 nm), which did not coalesce even after gelation, forming spherical CTZ-µEG (∼90 nm). However, the maturity of CTZ nanodroplets observed by dynamic light scattering suggests the affinity of CTZ for the nonpolar microenvironment, which was further supported by the peak-to-peak correlation of Fourier transform infrared (FTIR) analysis and fluorescence measurement. In addition, HPLC analysis showed that the in vitro permeation release of CTZ-µEG from rabbit skin in the ethanolic phosphate buffer (pH = 7.4) was significantly increased by >98% within 6.0 h. This indicates the sustained release of CTZ in µEBG and the improvement in transdermal therapeutic efficacy of CTZ over its traditional topical formulations.

Hyperbranched Polyethylenimine-Tethered Multiple Emulsion-Templated Hierarchically Macroporous Poly(acrylic acid)-Al2O3 Nanocomposite Beads for Water Purification.

Emulsion template-guided strategy has been used to produce porous architectures with exquisite structure, tailored morphology, and exclusive features for ubiquitous applications. Notwithstanding, the practical water remediation is often marred by their transport-limited behavior and fragility. To circumvent these conundrums, we prepared hierarchically porous poly(acrylic acid)-alumina nanocomposite beads by solidifying the droplets of emulsions jointly stabilized by the organic surfactants and alumina nanoparticles. By virtue of their positive charge, the alumina nanoparticles got entrapped within the poly(acrylic acid) scaffolds that excluded the risk of secondary contamination typically observed with conventional nanocomposites. Being amenable to surface modification, the carboxyl moieties of the beaded polymer were further exploited to covalently tether branched polyethylenimine throughout the exterior and interior surface of the porous matrix via a grafting-to approach. The macropores expedite an active fluid flow and easier adsorbate transport throughout the functionalized nanocomposites whose overall higher density of positive charge over a certain pH range electrostatically attracts and effectively adsorbs the negatively charged Cr(VI) complexes and anionic congo red ions/molecules from water. This proof-of-concept synthetic approach and postsynthetic modification offer an improved mechanical robustness to these macrosized multifunctional nanocomposite beads for their easier processing, thereby paving the way for the point-of-use water purification technology development.

A pH-sensitive, stimuli-responsive, superabsorbent, smart hydrogel from psyllium (Plantago ovata) for intelligent drug delivery.

Herein, we report a polysaccharide-based hydrogel isolated from psyllium husk (a well-known dietary fiber) and evaluated for its swelling properties in deionized water (DW) at different physiological pH values, i.e., 1.2, 6.8 and 7.4. Swelling of psyllium hydrogel (PSH) in DW under the influence of temperature and at different concentrations of NaCl and KCl solutions was also examined. A pH-dependent swelling pattern of PSH was observed following the order DW > pH 7.4 > pH 6.8 > pH 1.2. Stimuli-responsive swelling and deswelling (on-off switching) behavior of PSH was observed in DW and ethanol, DW and normal saline, at pH 7.4 and pH 1.2 environments, respectively. Similar swelling behavior and on-off switching attribute of PSH-containing tablets indicated the unaltered nature of PSH even after compression. Scanning electron micrographs of swollen and then freeze-dried PSH via transverse and longitudinal cross-sections revealed hollow channels with an average pore size of 6 ± 2 µm. Furthermore, PSH concentration-dependent sustained release of theophylline from tablet formulation was witnessed for >15 h following the non-Fickian diffusion mechanism. Subacute toxicity studies revealed the non-toxic nature of PSH. Therefore, dietary fiber-based material, i.e., PSH could be a valuable pharmaceutical excipient for intelligent and targeted drug delivery.

Facile Synthesis of Ultrastable Fluorescent Copper Nanoclusters and Their Cellular Imaging Application.

Copper nanoclusters (Cu NCs) are generally formed by several to dozens of atoms. Because of wide range of raw materials and cheap prices, Cu NCs have attracted scientists' special attention. However, Cu NCs tend to undergo oxidation easily. Thus, there is a dire need to develop a synthetic protocol for preparing fluorescent Cu NCs with high QY and better stability. Herein, we report a one-step method for preparing stable blue-green fluorescent copper nanoclusters using glutathione (GSH) as both a reducing agent and a stabilizing agent. High-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and electrospray ionization mass spectrometer (ESI-MS) were used to characterize the resulting Cu NCs. The as-prepared Cu NCs@GSH possess an ultrasmall size (2.3 ± 0.4 nm), blue-green fluorescence with decent quantum yield (6.2%) and good stability. MTT results clearly suggest that the Cu NCs@GSH are biocompatible. After incubated with EB-labeled HEK293T cells, the Cu NCs mainly accumulated in nuclei of the cells, suggesting that the as-prepared Cu NCs could potentially be used as the fluorescent probe for applications in cellular imaging.

Green synthesized selenium doped zinc oxide nano-antibiotic: synthesis, characterization and evaluation of antimicrobial, nanotoxicity and teratogenicity potential.

A facile, green synthesis of selenium doped zinc oxide nano-antibiotic (Se-ZnO-NAB) using the Curcuma longa extract is reported to combat the increased emergence of methicillin-resistant Staphylococcus aureus (MRSA). The developed Se-ZnO-NAB were characterized for their physicochemical parameters and extensively evaluated for their toxicological potential in an animal model. The prepared Se-ZnO-NABs were characterized via Fourier transformed infrared spectroscopy to get functional insight into their surface chemistry, scanning electron microscopy revealing the polyhedral morphology with a size range of 36 ± 16 nm, having -28.9 ± 6.42 mV zeta potential, and inductively coupled plasma optical emission spectrometry confirming the amount of Se and Zn to be 14.43 and 71.70 mg L-1 respectively. Moreover, the antibacterial activity against MRSA showed significantly low minimum inhibitory concentration at 6.2 µg mL-1 when compared against antibiotics. Also, total protein content and reactive oxygen species production in MRSA, under the stressed environment of Se-ZnO-NAB, significantly (p < 0.05) decreased compared to the negative control. Moreover, the results of acute oral toxicity in rats showed moderate variations in blood biochemistry and histopathology of vital organs. The teratogenicity and fetal evaluations also revealed some signs of toxicity along with changes in biochemical parameters. The overall outcomes suggest that Se-ZnO-NAB can be of significant importance for combating multi-drug resistance but must be used with extreme caution, particularly in pregnancy, as moderate toxicity was observed at a toxic dose of 2000 mg kg-1.

Formation of Antihyperlipidemic Nano-Ezetimibe from Volatile Microemulsion Template for Enhanced Dissolution Profile.

Nanostructures play an important role in targeting sparingly water-soluble drugs to specific sites. Because of the structural flexibility and stability, the use of template microemulsions (µEs) can produce functional nanopharmaceuticals of different sizes, shapes, and chemical properties. In this article, we report a new volatile oil-in-water (o/w) µE formulation comprising ethyl acetate/ethanol/brij-35/water to obtain the highly water-dispersible nanoparticles of an antihyperlipidemic agent, ezetimibe (EZM-NPs), to enhance its dissolution profile. A pseudoternary phase diagram was delineated in a specified brij-35/ethanol ratio (1:1) to describe the transparent, optically isotropic domain of the as-formulated µE. The water-dilutable µE formulation, comprising an optimum composition of ethyl acetate (18.0%), ethanol (25.0%), brij-35 (25.0%), and water (32.0%), showed a good dissolvability of EZM around 4.8 wt % at pH 5.2. Electron micrographs showed a fine monomodal collection of EZM-loaded µE droplets (∼45 nm) that did not coalesce even after lyophilization, forming small spherical EZM-NPs (∼60 nm). However, the maturity of nanodrug droplets observed through dynamic light scattering suggests the affinity of EZM to the nonpolar microenvironment, which was further supported through peak-to-peak correlation of infrared analysis and fluorescence measurements. Moreover, the release profile of the as-obtained EZM-nanopowder increased significantly >98% in 30 min, which indicates that a reduced drug concentration will be needed for capsules or tablets in the future and can be simply incorporated into the multidosage formulation of EZM.

Controlled Assembly of Cu/Co-Oxide Beaded Nanoclusters on Thiolated Graphene Oxide Nanosheets for High-Performance Oxygen Evolution Catalysts.

The use of water splitting modules is highly desired for the sustainable production of H2 as a future energy carrier. However, the sluggish kinetics and demand of high anodic potential are the bottlenecks for half-the cell oxygen evolution reaction (OER), which severely hamper the overall conversion efficiency. Although transition metal oxides based electrocatalysts have been envisioned as cost-effective and potential contenders for this quest, nevertheless, their low conductivity, instability, and limited number of active sites are among the common impediments that need to be addressed to eventually enhance their inherent catalytic potential for enhanced OER activity. Herein, the controlled assembly of transition metal oxides, that is, Cu@CuOx nanoclusters (NCs, ≈2 nm) and Co@CoOx beaded nanoclusters (BNCs, ≈2 nm), on thiol-functionalized graphene oxide (G-SH) nanosheets is reported to form novel and highly efficient electrocatalysts for OER. The thiol (-SH) functionality was incorporated by selective epoxidation on the surface of graphene oxide (GO) to achieve chemically exfoliated nanosheets to enhance its conductivity and trapping ability for metal oxides in nanoscale dimensions (≈2 nm). During the electrocatalytic reaction, overpotentials of 290 mV and 310 mV are required to achieve a current density of 10 mA cm-2 for BNCs and NCs, respectively, and the catalysts exhibit tremendous long-term stability (≈50 h) in purified alkaline medium (1 m KOH) with no dissolution in the electrolyte. Moreover, the smaller Tafel slopes (54 mV/dec for BNCs and 66 mV/dec for NCs), and a Faradic efficiency of approximately 96 % indicate not only the selectivity but also the tailored heterogeneous electrons transfer (HET) rate, which is required for fast electrode kinetics. It is anticipated that such ultrasmall metal oxide nanoclusters and their controlled assembly on a conducting surface (G-SH) may offer high electrochemical accessibility and a plethora of active sites owing to the drastic decrease in dimensions and thus can synergistically ameliorate the challenging OER process.