Dye degradation, antibacterial activity and molecular docking analysis of cellulose/polyvinylpyrrolidone-doped cadmium sulphide quantum dots

Synergistic Dual Antibacterial Activity of Magnetite Hydrogels Doped with Silver

In this work, we utilized poly-N-isopropylacrylamide (NIPAM), magnetic nanoparticles (MNPs), and silver nitrate to prepare magnetic hydrogel microparticles doped with silver, which exhibited a dual antimicrobial effect. The antibacterial effect of these composites was mediated by the antimicrobial activity of silver and the magnetic hyperthermic induction, which we believe increased biofilm disruption and silver release into the surrounding bacterial biofilms. The prepared particles were characterized by using several analytical techniques. The particles exhibited a porous morphology impregnated evenly with silver nanoparticles, as observed by scanning electron microscopy (SEM). Furthermore, we examined the antibacterial activity of our microparticles against Escherichia coli by determining the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Our findings revealed that the composites demonstrated significant antibacterial activity of up to 81% under magnetic hyperthermia as compared to 45% when samples were heated to the same temperature in a water bath at constant silver concentration. This demonstrates the distinctive inhibitory features of MNPs in enhancing bacterial killing when a magnetic field is applied. The findings of this study lay the groundwork for further exploration of microparticle-based antimicrobial therapies, which can contribute to the development of more advanced wound healing devices and better sterilization methods for medical devices.

Efficient Dye Degradation and Antimicrobial Behavior with Molecular Docking Performance of Silver and Polyvinylpyrrolidone-Doped Zn-Fe Layered Double Hydroxide

Zn-Fe layered double hydroxide (LDH) was synthesized through the low-temperature-based coprecipitation method. Various concentrations of Ag (1, 3, and 5 wt %) with a fixed amount (5 wt %) of polyvinylpyrrolidone (PVP) were doped into LDH nanocomposites. This research aims to improve the bactericidal properties and catalytic activities of doping-dependent nanocomposites. Adding Ag and PVP to LDH enhanced oxygen vacancies, which increased the amount of hydroxide adsorption sites and the number of active sites. The doped LDH was employed to degrade rhodamine-B dye in the presence of a reducing agent (NaBH4), and the obtained results showed maximum dye degradation in a basic medium compared to acidic and neutral. The bactericidal efficacy of doped Zn-Fe (5 wt %) showed a considerably greater inhibition zone of 3.65 mm against Gram-negative (G-ve) or Escherichia coli (E. coli). Furthermore, molecular docking was used to decipher the mystery behind the microbicidal action of Ag-doped PVP/Zn-Fe LDH and to propose an inhibition mechanism of β-ketoacyl-acyl carrier protein synthase IIE. coli (FabH) and deoxyribonucleic acid gyrase E. coli behind in vitro results.

Carbon sphere doped CdS quantum dots served as a dye degrader and their bactericidal behavior analysed with in silico molecular docking analysis

We have employed a co-precipitation method to synthesize different concentrations of carbon spheres (CSs) doped with cadmium sulfide (CdS) quantum dots (QDs) for catalytic reduction and antibacterial applications. Various morphological and structural characterization techniques were used to comprehensively analyze the CS effect on CdS QDs. The catalytic reduction efficiency of CS-doped CdS QDs was evaluated using rhodamine B dye. The antibacterial efficacy was also assessed against the pathogenic microorganism Escherichia coli (E. coli), and substantial destruction in the inhibitory zone was measured. Finally, the synthesized CS-doped CdS QDs demonstrated favorable results for catalytic reduction and antibacterial applications. Computational studies verified the suppressive impact of these formed QDs on DNA gyrase and β-lactamase of E. coli.

Recent advances in cellulose nanocrystals-based antimicrobial agents

Over the past five years, there has been growing interest in the design of modified cellulose nanocrystals (CNCs) as nanoscale antimicrobial agents in potential end-user applications such as food preservation/packaging, additive manufacturing, biomedical and water purification. The interest of applying CNCs-based antimicrobial agents arise due to their abilities to be derived from renewable bioresources and their excellent physicochemical properties including rod-like morphologies, large specific surface area, low toxicity, biocompatibility, biodegradability and sustainability. The presence of ample surface hydroxyl groups further allows easy chemical surface modifications for the design of advanced functional CNCs-based antimicrobial materials. Furthermore, CNCs are used to support antimicrobial agents that are subjected to instability issues. The current review summarizes recent progress in CNC-inorganic hybrid-based materials (Ag and Zn nanoparticles, other metal/metal oxide) and CNC-organic hybrid-based materials (polymers, chitosan, simple organic molecules). It focuses on their design, syntheses and applications with a brief discussion on their probable modes of antimicrobial action whereby the roles of CNCs and/or the antimicrobial agents are highlighted.

In-vitro synergistic microbicidal and catalytic evaluation of polyvinylpyrrolidone/chitosan doped tungsten trioxide nanoplates with evidential in-silico analysis

In this research, hydrothermally synthesized tungsten trioxide (WO₃) nanocomposites doped polyvinylpyrrolidone (PVP) and chitosan (CS) were studied. Various concentrations (3, 6, and 9 wt%) of PVP were doped into a fixed amount of binary system (CS-WO₃) nanocomposites. PVP/CS polymers showed attractive attention because of their different structure, functionality, and architecture control as dopant to WO₃. The PVP/CS encapsulates the WO₃ (ternary composite), which controls crystallite size (band gap reduction), rapidly overcomes the recombination electron-hole pairs issues, and generates the active sites, resulting in improved catalytic and antimicrobial activity. The synthesized nanocomposites revealed significant catalytic efficiency and methylene blue (MB) dye depletion of 99.9 % in the presence of reducing agent (NaBH₄) in neutral and acidic media. Antimicrobial effectiveness of produced nanostructures towards Escherichia coli (E. coli) pathogen at low and high concentrations were investigated by Vernier caliper in mm. Furthermore, to their microbicidal action, docking experiments of CS-doped WO₃ and PVP/CS-doped WO₃ nanostructures for DHFR and FabI of Escherichia coli suggested blockage of aforesaid enzymes as the plausible pathway.

Recent advances of antibacterial starch-based materials

Starch has attracted a lot of attention because it is biodegradable, renewable, nontoxic and low cost. By adding antibacterial substances to starch, starch-based materials have antibacterial properties. The composite with other materials can improve the comprehensive performance of starch-based materials, thus broadening the application field of the material. In this paper, we focus on antibacterial starch-based materials and review their preparation and applications. It was found that antibacterial starch-based materials were most widely used in packaging, followed by medicine, and the research on smart starch-based materials was relatively less. This review may provide some reference value for subsequent studies of starch-based materials.

Facile Synthesis of Barium-Doped Cadmium Sulfide Quantum Dots for the Treatment of Polluted Water: Experimental and Computational Investigations

In this study, cadmium sulfide (CdS) quantum dots (QDs) and barium (Ba) (3 and 6 wt %)-doped CdS QDs were synthesized via a hydrothermal technique. The basic purpose of this work is to degrade methylene blue (MB) dye and evaluate density functional theory (DFT). The synthesized samples were characterized through X-ray powder diffraction (XRD), selected area electron diffraction (SAED), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), high-resolution transmission electron microscopy (HR-TEM), UV-vis spectrophotometer, PL, and density functional theory (DFT). The XRD (structural analysis) confirmed that the hexagonal crystal structure and crystallinity increased upon doping. Selected area electron diffraction (SAED) analysis confirmed the polycrystalline nature of the prepared QDs. The functional groups have been investigated using FTIR analysis. The surface and structural morphologies of the synthesized specimen have been investigated by applying TEM and FE-SEM, and it was found to exhibit the topology of QDs. In addition, optical characteristics have been investigated via UV-vis absorption spectroscopy, which exhibited a bathochromic shift (red shift) as a consequence of the reduction of the band-gap energy upon doping from 2.56 to 2.38 eV. PL analysis was used to observe the electron-hole recombination rate. Moreover, the electronic and optical properties of Ba-doped CdS were further explored using density functional theory. Pristine and Ba-doped QDs exhibit sufficient catalytic activity (CA) against the MB dye in all media as 62.59, 70.15, and 72.74% in neutral, basic, and acidic solutions, respectively.

Cation Incorporation and Synergistic Effects on the Characteristics of Sulfur-Doped Manganese Ferrites S@Mn(Fe2O4) Nanoparticles for Boosted Sunlight-Driven Photocatalysis

In the present work, sulfur-doped manganese ferrites S@Mn(Fe₂O₄) nanoparticles were prepared by using the sol-gel and citrate method. The concentration of sulfur varied from 1 to 7% by adding Na₂S. The samples were characterized by performing Fourier Transformed Infrared Spectroscopy (FTIR), Energy Dispersive X-ray (EDX), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Ultraviolet-Visible spectroscopy (UV-Visible). The synthesized sulfur-doped manganese ferrites were applied to evaluate the photocatalytic degradation of the dyes. Further, the degradation studies revealed that the nanoparticles successfully degraded the methylene blue dye by adding a 0.006 g dose under the sunlight. The sulfur-doped manganese ferrite nanoparticles containing 3% sulfur completely degraded the dye in 2 h and 15 min in aqueous medium. Thus, the ferrite nanoparticles were found to be promising photocatalyst materials and could be employed for the degradation of other dyes in the future.