Novel Ag/cellulose-doped CeO2 quantum dots for efficient dye degradation and bactericidal activity with molecular docking study

Nanomaterials Regulate Bacterial Quorum Sensing: Applications, Mechanisms, and Optimization Strategies

Anti-virulence therapy that interferes with bacterial communication, known as "quorum sensing (QS)", is a promising strategy for circumventing bacterial resistance. Using nanomaterials to regulate bacterial QS in anti-virulence therapy has attracted much attention, which is mainly attributed to unique physicochemical properties and excellent designability of nanomaterials. However, bacterial QS is a dynamic and multistep process, and there are significant differences in the specific regulatory mechanisms and related influencing factors of nanomaterials in different steps of the QS process. An in-depth understanding of the specific regulatory mechanisms and related influencing factors of nanomaterials in each step can significantly optimize QS regulatory activity and enhance the development of novel nanomaterials with better comprehensive performance. Therefore, this review focuses on the mechanisms by which nanomaterials regulate bacterial QS in the signal supply (including signal synthesis, secretion, and accumulation) and signal transduction cascade (including signal perception and response) processes. Moreover, based on the two key influencing factors (i.e., the nanomaterial itself and the environment), optimization strategies to enhance the QS regulatory activity are comprehensively summarized. Collectively, applying nanomaterials to regulate bacterial QS is a promising strategy for anti-virulence therapy. This review provides reference and inspiration for further research on the anti-virulence application of nanomaterials.

Size-controlled synthesis of La and chitosan doped cobalt selenide nanostructures for catalytic and antibacterial activity with molecular docking analysis

Co-precipitation method was adopted to synthesize ternary heterostructure catalysts La/CS-CoSe NSs (lanthanum/chitosan‑cobalt selenide nanostructures) without the use of a surfactant. During synthesis, a fixed amount (3 wt%) of CS was doped with 2 and 4 wt% La to control the growth, recombination rate and stability of CoSe NSs. The doped samples served to enhance the surface area, porosity and active sites for catalytic degradation of rhodamine B dye and antibacterial potential against Staphylococcus aureus (S. aureus). Additionally, the synthesized catalysts were examined for morphological, structural and optical characteristics to assess the influence of dopants to CoSe. XRD spectra verified the hexagonal and cubic structure of CoSe, whereas the porosity of the undoped sample (CoSe) increased from 45 to 60 % upon incorporation of dopants (La and Cs). Among the samples analyzed during this study, 4 % La/CS-CoSe exhibited significant bactericidal behavior as well as the highest catalytic reduction of rhodamine B dye in a neutral environment. Molecular docking analysis was employed to elucidate the underlying mechanism behind the bactericidal activity exhibited by CS-CoSe and La/CS-CoSe NSs against DHFRS. aureus and DNA gyraseS. aureus.

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.

Synthesis of curcuma longa doped cellulose grafted hydrogel for catalysis, bactericidial and insilico molecular docking analysis

Curcumin (diferuloylmethane), the primary curcuminoid in turmeric rhizome, has been acknowledged as a bioactive compound for numerous pharmacological activities. Nonetheless, the hydrophobic nature, rapid metabolism, and physicochemical and biological instability of this phenolic compound correspond to its poor bioavailability. So, recent scientific advances have found many components and strategies for enhancing the bioavailability of curcumin with the inclusion of biotechnology and nanotechnology to address its existing limitations. Therefore, In this study, copolymerized aqua-gel was synthesized by graft polymerization of poly-acrylic acid (P-AA) on cellulose nanocrystals (CNC), after that Curcuma longa (Cur) was incorporated as dopant (5, 10, 15, and 25 mg) in hydrogel (Cur/C-P) as a stabilizing agent for evaluation of bacterial potential and sewage treatment. The antioxidant tendency of 25 mg Cur/C-P was much higher (72.21 %) than other samples and displayed a catalytic activity of up to 93.89 % in acidic conditions and optimized bactericidal inclinations toward gram-positive bacterial strains. Furthermore, ligand binding was conducted against targeted protein enoyl-[acylcarrier-protein] reductase (FabI) enzyme to comprehend the putative mechanism of microbicidal action of CNC-PAA (CP), Cur/C-P, and curcumin. Our outcomes suggest that 25 mg Cur/C-P hydrogels are plausible sources for hybrid, multifunctional biological activity.

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.

Structural and functional insights in polysaccharides coated cerium oxide nanoparticles and their potential biomedical applications: A review

Cerium oxide nanoparticles have now significant presence in biomedical fields due to their wide applications; however, challenges regarding their safety and biocompatibility persist. Polysaccharides based biopolymers have inherent hydroxyl and carboxyl groups, enabling them to govern the surface functionalization of cerium oxide nanoparticles, hence their chemical and physical characteristics. Because of this, polysaccharides such as dextran, alginate, pullulan, chitosan, polylactic acid, starch, and pectin are practical substitutes for the conventional coatings used to synthesize cerium oxide nanoparticles. This review discusses the effect of biopolymer coatings on the properties of cerium oxide nanoparticles, such as size, stability, aggregation, and biocompatibility. Additionally, it also summarises various biomedical applications of polysaccharides coated cerium oxide nanoparticles, such as in bone tissue regeneration, liver inflammation, wound healing, and antibacterial and anticancer activities. Biocompatible cerium oxide nanoparticles will surely improve their applications in the biomedical field.

Facile Synthesis of Vanadium Oxide/Carbon Spheres-Doped Nickel Oxide Functioned as a Nanocatalyst and Bactericidal Behavior with Molecular Docking Analysis

Vanadium oxide (V₂O₅) and carbon spheres (Cs)-doped NiO₂ nanostructures (NSs) were prepared using the co-precipitation approach. Several spectroscopic and microscopic techniques, including X-ray diffraction (XRD), UV-vis, FTIR, TEM, and HR-TEM investigations, were used to describe the as-synthesized NSs. The XRD pattern exhibited the hexagonal structure, and the crystallite size of pristine and doped NSs was calculated as 29.3, 32.8, 25.79, and 45.19 nm, respectively. The control sample (NiO₂) showed maximum absorption at 330 nm, and upon doping, a redshift was observed, leading to decreased band gap energy from 3.75 to 3.59 eV. TEM of NiO₂ shows agglomerated nonuniform nanorods exhibited with various nanoparticles without a specific orientation; a higher agglomeration was observed upon doping. The (4 wt %) V₂O₅/Cs-doped NiO₂ NSs served as superior catalysts with a 94.21% MB reduction in acidic media. The significant antibacterial efficacy was estimated against Escherichia coli by measuring the zone of inhibition (3.75 mm). Besides their bactericidal analysis, V₂O₅/Cs-doped NiO₂ was shown to have a binding score of 6.37 for dihydrofolate reductase and a binding score of 4.31 for dihydropteroate synthase in an in silico docking study of E. coli.

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.

Facile synthesis of copolymerized cellulose grafted hydrogel doped calcium oxide nanocomposites with improved antioxidant activity for anti-arthritic and controlled release of doxorubicin for anti-cancer evaluation

The combination treatment is considered an approach to attaining synergistic impact while minimizing applied dosage. Hydrogels are analogous to the tissue environment attributed to hydrophilic and porous structure. Despite extensive study in biological and biotechnological domains, their restricted mechanical strength and limited functionalities impede their potential uses. Emerging strategies are centred on research and developing nanocomposite hydrogels to combat these issues. Herein, we prepared copolymerized hydrogel by grafting poly-acrylic acid P(AA) onto cellulose nanocrystals (CNC) and adding CNC-g-PAA as dopant (2 and 4 wt%) in calcium oxide (CaO) nanoparticles to generate an effective hydrogel doped nanocomposite (NCH) (CNC-g-PAA/CaO) for biomedical applications such as anti-arthritic, anti-cancer, and antibacterial investigations alongside their comprehensive characterization. CNC-g-PAA/CaO (4 %), compared to other samples, had a substantially higher antioxidant potential (72.21 %). Doxorubicin, a potential chemotherapeutic drug, was then effectively loaded into NCH (99 %) via electrostatic interaction, and pH-triggered based release was found to be >57.9 % in 24 h. Furthermore, molecular docking investigation against targeted protein Cyclin-dependent kinase 2 and in vitro cytotoxicity study verified the improved antitumor effectiveness of CNC-g-PAA and CNC-g-PAA/CaO. These outcomes indicated that hydrogels might serve as potential delivery vehicles for innovative multifunctional biomedical applications.

Assessment of catalytic, antimicrobial and molecular docking analysis of starch-grafted polyacrylic acid doped BaO nanostructures

The removal of cationic dyes from water has received a great attention of researchers considering their influence on environment and ecosystem. In current work, starch-grafted-poly acrylic acid (St-g-PAA) doped BaO nanostrucutures have been synthesized by co-precipitation approach. The aim of this research was to reduce the harmful methylene blue dye and evaluate the antibacterial activity of St-g-PAA doped BaO. XRD spectra exhibited the tetragonal structure of BaO and no variations occurred upon doping. The optical properties of St-g-PAA doped BaO have been evaluated by UV-Vis spectrophotometer. The existence of a dopant in the product was verified using EDS spectroscopy. TEM revealed the formation of cubic-shaped NPs of BaO and upon the addition of St-g-PAA, a few nanorod-like structures. The higher concentration of St-g-PAA doped BaO exhibit a remarkable reduction of methylene blue in a basic environment. Furthermore, St-g-PAA doped BaO revealed higher antimicrobial efficacy against Staphylococcus aureus in comparison to Escherichia coli. In silico studies were conducted against enoyl-[acylcarrier-protein] reductase (FabI) and beta-lactamase enzyme to evaluate the potential of both St-g-PAA and St-g-PAA doped BaO nanocomposites as their inhibitors and to rationalize their possible mode of action.

Toward Efficient Bactericidal and Dye Degradation Performance of Strontium- and Starch-Doped Fe2O3 Nanostructures: In Silico Molecular Docking Studies

In this study, various concentrations of strontium (Sr) into a fixed amount of starch (St) and Fe₂O₃ nanostructures (NSs) were synthesized with the co-precipitation approach to evaluate the antibacterial and photocatalytic properties of the concerned NSs. The study aimed to synthesize nanorods of Fe₂O₃ with co-precipitation to enhance the bactericidal behavior with dopant-dependent Fe₂O₃. Advanced techniques were utilized to investigate the structural characteristics, morphological properties, optical absorption and emission, and elemental composition properties of synthesized samples. Measurements via X-ray diffraction confirmed the rhombohedral structure for Fe₂O₃. Fourier-transform infrared analysis explored the vibrational and rotational modes of the O-H functional group and the C=C and Fe-O functional groups. The energy band gap of the synthesized samples was observed in the range of 2.78-3.15 eV, which indicates that the blue shift in the absorption spectra of Fe₂O₃ and Sr/St-Fe₂O₃ was identified with UV-vis spectroscopy. The emission spectra were obtained through photoluminescence spectroscopy, and the elements in the materials were determined using energy-dispersive X-ray spectroscopy analysis. High-resolution transmission electron microscopy micrographs showed NSs that exhibit nanorods (NRs), and upon doping, agglomeration of NRs and nanoparticles was observed. Efficient degradations of methylene blue increased the photocatalytic activity in the implantation of Sr/St on Fe₂O₃ NRs. The antibacterial potential for Escherichia coli and Staphylococcus aureus was measured against ciprofloxacin. E. coli bacteria exhibit inhibition zones of 3.55 and 4.60 mm at low and high doses, respectively. S. aureus shows the measurement of inhibition zones for low and high doses of prepared samples at 0.47 and 2.40 mm, respectively. The prepared nanocatalyst showed remarkable antibacterial action against E. coli bacteria rather than S. aureus at high and low doses compared to ciprofloxacin. The best-docked conformation of the dihydrofolate reductase enzyme against E. coli for Sr/St-Fe₂O₃ showed H-bonding interactions with Ile-94, Tyr-100, Tyr-111, Trp-30, ASP-27, Thr-113, and Ala-6.

Graphitic-C3N4/chitosan-doped NiO nanostructure to treat the polluted water and their bactericidal with in silico molecular docking analysis

Different concentrations (2 and 4 wt%) of graphite carbon nitride (g-C3N4) was doped into fixed amount of chitosan (CS) and nickel oxide (NiO) nanoparticles (NPs) via a co-precipitation route. The aim of study is to remove the pollutants from wastewater through catalytic activity (CA) and determine the bactericidal activities of synthesized products. X-ray diffraction pattern confirmed the cubic structure of NiO NPs and peak shifted to higher angle upon g-C3N4 doping. Fourier transform infrared spectroscopy revealed the existence of bending and stretching vibration mode. The absorption decreased gradually accompanied blue-shift and assessed bandgap energy increased upon doping. The high resolution transmission electron microscopy micrographs confirmed the formation of cubic-shaped NPs and elongated nanorods were seen for NiO and co-doped NiO. The catalytic efficiency of samples was examined using methylene blue (MB) in the presence of reducing agent. A remarkable dye de-colorization was confirmed with a g-C3N4 and CS doping; moreover, the bactericidal efficacy compared to Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) was observed as 3.15 and 13.8 mm, respectively. In silico, molecular docking investigations targeting against b-lactamaseS. aureus and FabHE. coli enzymes assisted to elaborate the mechanism underlying microbicidal action of the NPs.

Experimental and theoretical study of catalytic dye degradation and bactericidal potential of multiple phase Bi and MoS2 doped SnO2 quantum dots†

In the present study, different concentrations (1 and 3%) of Bi were incorporated into a fixed amount of molybdenum disulfide (MoS₂) and SnO₂ quantum dots (QDs) by co-precipitation technique. This research aimed to increase the efficacy of dye degradation and bactericidal behavior of SnO₂. The high recombination rate of SnO₂ can be decreased upon doping with two-dimensional materials (MoS₂ nanosheets) and Bi metal. These binary dopants-based SnO₂ showed a significant role in methylene blue (MB) dye degradation in various pH media and antimicrobial potential as more active sites are provided by nanostructured MoS₂ and Bi³⁺ is responsible for producing a variety of different oxygen vacancies within SnO₂. The prepared QDs were described via morphology, optical characteristics, elemental composition, functional group, phase formation, crystallinity, and d-spacing. In contrast, antimicrobial activity was checked at high and low dosages against Escherichia coli (E. coli) and the inhibition zone was calculated utilizing a Vernier caliper. Furthermore, prepared samples have expressed substantial antimicrobial effects against E. coli. To further explore the interactions between the MB and Bi/MoS₂–SnO₂ composite, we modeled and calculated the MB adsorption using density functional theory and the Heyd–Scuseria–Ernzerhof hybrid (HSE06) approach. There is a relatively strong interaction between the MB molecule and Bi/MoS₂–SnO₂ composite.

In the present study, different concentrations (1 and 3%) of Bi were incorporated into a fixed amount of molybdenum disulfide and SnO₂ quantum dots by co-precipitation technique. This research aimed to increase the efficacy of dye degradation and bactericidal behavior of SnO₂.

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.

Comparative Study of Sonophotocatalytic, Photocatalytic, and Catalytic Activities of Magnesium and Chitosan-Doped Tin Oxide Quantum Dots

The present study demonstrates the hydrothermal synthesis of SnO₂ quantum dots (QDs) doped with different concentrations (2, 4 wt %) of magnesium (Mg) and a fixed amount of chitosan (CS). The obtained samples were investigated through a number of characterizations for optical analysis, elemental composition, crystal structure, functional group presence, interlayer spacing, and surface morphology. The XRD spectrum revealed the tetragonal structure of SnO₂ with no significant variations occurring upon the addition of CS and Mg. The crystallite size of QDs was reduced by incorporation of dopants. The optical absorption spectra revealed a red shift, assigned to the reduction of the band gap energy upon doping. TEM analysis proved that the few nanorod-like structures of CS overlapped with SnO₂ QDs, and agglomeration was observed upon Mg doping. The incorporation of dopants little enhanced the d-spacing of SnO₂ QDs. Moreover, the synthesized nanocatalyst was utilized to calculate the degradation percentage of methylene blue (MB) dye. Afterward, a comparative analysis of catalytic activity, photocatalytic activity, and sonophotocatalytic activity was carried out. Notably, 4% Mg/CS-doped QDs showed maximum sonophotocatalytic degradation of MB in basic medium compared to other activities. Lastly, the prepared nanocatalyst was found to be efficient for dye degradation in any environment and inexpensive.

Formation of biocompatible MgO/cellulose grafted hydrogel for efficient bactericidal and controlled release of doxorubicin

In this study, MgO-doped CNC-g-PAA hydrogel was synthesized by grafting poly (acrylic acid) (PAA) onto cellulose nanocrystals (CNC) and then doped Magnesium oxide (MgO) using pH 7.0 and 12.0 to obtain an efficient nanocomposite hydrogel for antibacterial and anti-cancer activities. The synthesized nanocomposite hydrogels were evaluated by detailed characterization and confirmed the formation of a well-interconnected porous structure. MgO/CNC-g-PAA (pH = 12.0) exhibited improved bactericidal tendencies towards gram-negative and gram-positive bacteria, which was further investigated by in-silico molecular docking analyses and also examined the reactive oxygen species production by photocatalysis and free radical-scavenging assay. After this, Doxorubicin (DOX), a model anticancer drug, was successfully loaded into nanocomposites (~79 %) by electrostatic interaction and confirmed pH-triggered based release, which was over 53.7 % in 24 h. Finally, in vitro cytotoxicity-based analysis confirmed the improved antitumor efficacy of nanocomposite hydrogels. These findings revealed that MgO/CNC-g-PAA hydrogels might be prospective carriers for controlled drug delivery.

Facile Synthesis of La- and Chitosan-Doped CaO Nanoparticles and Their Evaluation for Catalytic and Antimicrobial Potential with Molecular Docking Studies

In the current study, a low-cost and straightforward coprecipitation technique was adopted to synthesize CaO and La-doped CS/CaO NPs. Different weight ratios (2 and 4) of La were doped into fixed amounts of CS and CaO. Synthesized samples exhibited outstanding catalytic performance by degrading methylene blue (MB) in a highly efficient manner. The X-ray diffraction technique detected the presence of a cubic phase of CaO and a decrease in crystallite size of the samples with the addition of La. Fourier transform infrared spectroscopy confirmed the presence of the dopant and the base material with functional groups at 712 cm^-1. A decrease in the absorption intensity of doped CaO was observed with an increasing amount of dopants La and CS accompanied by a blueshift leading to an increase in the band gap energy from 4.17 to 4.42 eV, as recorded with an ultraviolet-visible spectrophotometer. The presence of dopants (La and CS) and the evaluation of the elemental constitution of Ca and O were supported with the energy-dispersive spectroscopy technique. In an acidic medium, the catalytic activity against the MB dye was reduced (93.8%) for 4% La-doped CS/CaO. For La-doped CS/CaO, vast inhibition domains ranged within 4.15-4.70 and 5.82-8.05 mm against Escherichia coli while 4.15-5.20 and 6.65-13.10 mm against Staphylococcus aureus (S. aureus) at the least and maximum concentrations, correspondingly. In silico molecular docking studies suggested these nanocomposites of chitosan as possible inhibitors against the enoyl-acyl carrier protein reductase (FabI) from S. aureus.

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

In present study, control sized cadmium sulphide (CdS) quantum dots (QDs) and cellulose nanocrystals grafted polyvinylpyrrolidone (CNC-g-PVP) doped CdS QDs were synthesized via co-precipitation. The suggested pathway is fruitful in throwing out organic pollutants like methylene blue (MB) from industrial water and bactericidal applications. A series of characterization techniques were used to determine the structural, optical and morphological qualities of prepared samples. The X-ray diffraction (XRD) pattern verified hexagonal structure with no significant change occurring in the spectrum upon doping (2, 4, and 6 %). The UV-vis spectrophotometer describes blueshift in absorption pattern, resulting in an increase in band gap energy (E_g) upon doping. Catalytic activity (CA) against MB in basic and neutral medium demonstrated remarkable results compared with the acidic medium. Furthermore, bactericidal potential of doped sample (6 %) exhibited the significantly higher inhibition zones of 5.25 mm and 4.05 mm against Staphylococcus aureus (S. aureus) or Gram-positive (G₊ve) and Escherichia coli (E. coli) or Gram-negative (G-ve), respectively. In silico predictions for these doped QDs were performed against selected enzyme targets (i.e. DNA gyrase and FabI) to unveil the mystery governing these bactericidal activities.

Evaluation of bactericidal potential and catalytic dye degradation of multiple morphology based chitosan/polyvinylpyrrolidone-doped bismuth oxide nanostructures

In this study, 0.02 and 0.04 wt% of chitosan (CS) were successfully incorporated in a fixed amount of polyvinylpyrrolidone (PVP)-doped Bi₂O₃ nanostructures (NSs) via a co-precipitation approach. The purpose of this research was to degrade hazardous methylene blue dye and assess antimicrobial potential of the prepared CS/PVP-doped Bi₂O₃ nanostructures. In addition, optical characteristics, charge recombination rate, elemental composition, phase formation, surface morphology, functional groups, d-spacing, and crystallinity of the obtained nanostructures were investigated. CS/PVP-doped Bi₂O₃ nanostructures exhibited efficient catalytic activity (measured as 99%) in a neutral medium for dopant-free nanostructures while the inhibition zone was measured using a Vernier caliper against pathogens Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) at low and high doses to check antimicrobial activity. Strong bactericidal action was recorded against S. aureus bacteria such that a significant inhibition zone was measured at 3.09 mm.

Novel Ta/chitosan-doped CuO nanorods for catalytic purification of industrial wastewater and antimicrobial applications

Novel tantalum (Ta) and chitosan (CS)-doped CuO nanorods (NRs) were synthesized using a single step co-precipitation route. Different concentrations (2 and 4%) of Ta were used in fixed amounts of CS and CuO to examine their catalytic activity and antimicrobial potential. For critical analysis, synthesized NRs were systematically examined using XRD, FTIR HRTEM, EDS, UV-Vis and PL spectroscopy. The XRD technique revealed the monoclinic structure of CuO while an increase in its crystallite size (from 15.5 to 18.5 nm) was observed upon doping. FTIR spectra were examined to study the functional groups of CuO where peaks at 514 cm-1 and 603 cm-1 confirmed the formation of CuO NRs. PL spectra depicted the charge transfer efficiency of the synthesized samples. The presence of dopants (Ta and CS) and constituent elements (Cu, O) was detected using EDS spectra. Additionally, the pH based catalytic performance of fabricated NRs revealed 99.7% dye degradation of toxic methylene blue (MB) dye in neutral media, 99.4% in basic media and 99.5% in acidic media along with promising antibacterial activities for Gram negative/positive bacteria, respectively upon doping of Ta (4%) into CS/CuO. The adsorption energies of CuO co-doped with CS/Ta led to the creation of stable structures that were investigated theoretically using density functional theory.

In-silico predicting as a tool to develop plant-based biomedicines and nanoparticles: Lycium shawii metabolites

INTRODUCTION AND PURPOSE

In silico approach helps develop biomedicines and is useful for exploring the pharmacology of potential therapeutics using computer-simulated models. In vitro assays were used to determine the anti-microbial and cytotoxic efficacies of silver nanoparticles (AgNPs) synthesized with the shrub Lycium shawii.

METHODS

In silico predicting was performed to assess the L. shawii metabolites identified using QTOF-LCMS for their pharmacological properties. L. shawii mediated AgNPs were synthesized and characterized (FTIR, TEM, SEM, DLS and EDX). The anti-bacterial efficacies of L. shawii extract, AgNPs, and penicillin-conjugated AgNPs (pen-AgNPs) were determined. The cytotoxicity of the AgNPs was measured against colorectal cancer cell line (HCT116), normal breast epithelium (MCF 10 A), and breast cancer cell line (MDA MB 231).

RESULTS AND DISCUSSION

Five molecules (costunolide, catechin, emodin, lyciumaside, and aloe emodin 11-O-rhamnoside) were detected in the L. shawii extract. AgNPs (69 nm) were spherical with crystallographic structure. All three agents prepared showed inhibitory activity against the tested bacteria, the most efficacious being pen-AgNPs. High cytotoxicity of AgNPs (IC₅₀ 62 μg/ml) was observed against HCT116, IC₅₀ was 78 μg/ml for MCF 10 A, and 250 μg/ml for MDA MB 231, of which cells showed apoptotic features under TEM examination. The in silico approach indicated that the carbonic anhydrase IX enzyme was the target molecule mediating anti-cancer and anti-bacterial activities and that emodin was the metabolite in action.

CONCLUSIONS

Combining in vitro studies and in silico molecular target prediction helps find novel therapeutic agents. Among L. shawii metabolites, emodin is suggested for further studies as an agent for drug development against pathogenic bacteria and cancer.

Experimental and Computational Study of Zr and CNC-Doped MnO2 Nanorods for Photocatalytic and Antibacterial Activity

Cellulose nanocrystals (CNC), MnO₂, CNC-doped MnO₂, and Zr/CNC-doped MnO₂ were prepared with a hydrothermal method to assess their photocatalytic and antibacterial properties. Various characterizations were undertaken to determine the phase composition, the existence of functional units, optical characteristics, elemental analysis, surface topography, and microstructure of the prepared materials. Sample crystallinity was improved, whereas a decrease in crystallite size was observed with increasing amounts of dopants. Incorporation of dopants (CNC and Zr) into MnO₂ instigated a transformation in morphology from nanoclusters to nanorods with different diameters. Furthermore, photocatalytic activity experiments indicated a more effective degradation of methylene blue (MB) dye with CNC-doped MnO₂ and Zr/CNC-codoped MnO₂ while enhancing the bacterial efficacy for both G +ve and G -ve. Density functional theory was utilized to model the structures and elucidate their bonding and charge transfer mechanisms. The Zr/CNC-MnO₂ system showed charge depletion around Mn atoms, while charges were observed to accumulate around oxygen atoms.

The Use of Cerium Compounds as Antimicrobials for Biomedical Applications

Cerium and its derivatives have been used as remedies for wounds since the early 20th century. Cerium nitrate has attracted most attention in the treatment of deep burns, followed later by reports of its antimicrobial properties. Its ability to mimic and replace calcium is presumed to be a major mechanism of its beneficial action. However, despite some encouraging results, the overall data are somewhat confusing with seemingly the same compounds yielding opposing results. Despite this, cerium nitrate is currently used in wound treatment in combination with silver sulfadiazine as Flammacérium. Cerium oxide, especially in nanoparticle form (Nanoceria), has lately captured much interest due to its antibacterial properties mediated via oxidative stress, leading to an increase of published reports. The properties of Nanoceria depend on the synthesis method, their shape and size. Recently, the green synthesis route has gained a lot of interest as an alternative environmentally friendly method, resulting in production of effective antimicrobial and antifungal nanoparticles. Unfortunately, as is the case with antibiotics, emerging bacterial resistance against cerium-derived nanoparticles is a growing concern, especially in the case of bacterial biofilm. However, diverse strategies resulting from better understanding of the biology of cerium are promising. The aim of this paper is to present the progress to date in the use of cerium compounds as antimicrobials in clinical applications (in particular wound healing) and to provide an overview of the mechanisms of action of cerium at both the cellular and molecular level.

Synthesis and defect characterization of hybrid ceria nanostructures as a possible novel therapeutic material towards COVID-19 mitigation

This study reports the synthesis of hybrid nanostructures composed of cerium dioxide and microcrystalline cellulose prepared by the microwave-assisted hydrothermal route under distinct temperature and pH values. Their structural, morphological and spectroscopic behaviors were investigated by X-Rays Diffraction, Field Emission Gun Scanning Electron Microscopy, High-Resolution Transmission Electron Microscopy, and Fourier-Transform Infrared, Ultraviolet–Visible, Raman and Positron Annihilation Lifetime spectroscopies to evaluate the presence of structural defects and their correlation with the underlying mechanism regarding the biocide activity of the studied material. The samples showed mean crystallite sizes around 10 nm, characterizing the formation of quantum dots unevenly distributed along the cellulose surface with a certain agglomeration degree. The samples presented the characteristic Ce–O vibration close to 450 cm⁻¹ and a second-order mode around 1050 cm⁻¹, which is indicative of distribution of localized energetic levels originated from defective species, essential in the scavenging of reactive oxygen species. Positron spectroscopic studies showed first and second lifetime components ranging between 202–223 ps and 360–373 ps, respectively, revealing the presence of two distinct defective oxygen species, in addition to an increment in the concentration of Ce³⁺-oxygen vacancy associates as a function of temperature. Therefore, we have successfully synthesized hybrid nanoceria structures with potential multifunctional therapeutic properties to be further evaluated against the COVID-19.

Improved catalytic activity and bactericidal behavior of novel chitosan/V2O5 co-doped in tin-oxide quantum dots

The novel V₂O₅/chitosan (CS) co-doped tin oxide (SnO₂) quantum dots (QDs) were synthesized via co-precipitation technique. The optical, structural, morphological, and catalytic properties of the concerned specimens were examined by UV-Vis, PL, FTIR, X-ray diffraction, HR-TEM, and EDS. Structural analysis through XRD confirmed the tetragonal structure of SnO₂; meanwhile, HR-TEM measurements unveiled quantum dot morphology. Rotational and vibrational modes related to functional groups of (O–H, C–H, Sn–O, and Sn–O–Sn) have been assessed with FTIR spectra. Through UV-Vis spectroscopy, a reduction in band-gap (4.39 eV to 3.98 eV) and redshift in co-doped spectra of SnO₂ were identified. Both CS/SnO₂ and V₂O₅-doped CS@SnO₂ showed promising catalytic activity in all media. Meanwhile, CS/SnO₂ showed higher activity for use in hospital and industrial dye degradation in comparison to dopant-free Ch/SnO₂. For V₂O₅/CS@ SnO₂ QDs, inhibition domains of G –ve were significantly confirmed as 1.40–4.15 mm and 1.85–5.45 mm; meanwhile, for G +ve were noticed as 2.05–4.15 mm and 2.40–5.35 mm at least and maximum concentrations, correspondingly. These findings demonstrate the efficient role of V₂O₅/CS@SnO₂ QDs towards industrial dye degradation and antimicrobial activity.

Figure showing bactericidal mechanism exhibited by the prepared pristine and co-doped SnO₂.

MoS2/cellulose-doped ZnO nanorods for catalytic, antibacterial and molecular docking studies

Cellulose nanocrystals (CNCs) and molybdenum disulphide (MoS₂) incorporated into ZnO nanorods (NRs) were synthesized via a chemical precipitation route at room temperature. All concerned samples were characterized to examine their optical properties, elemental composition, phase formation, surface morphology and functional group presence. The aim of this research was to enhance the catalytic properties of ZnO by co-doping with various concentrations of CNCs and MoS₂ NRs. It was renowned that doped ZnO NRs showed superior catalytic activity compared to bare ZnO NRs. Statistically significant (p < 0.05) inhibition zones for samples were recorded for E. coli and S. aureus at low and high concentrations, respectively. The in vitro bactericidal potential of ZnO-CNC and ZnO-CNC-MoS₂ nanocomposites was further confirmed through in silico molecular docking predictions against the DHFR and DHPS enzymes of E. coli and S. aureus. Molecular docking studies suggested the inhibition of these enzyme targets by CNC nanocomposites as a possible mechanism governing their bactericidal activity.

Removal of heavy metal ion cobalt (II) from wastewater via adsorption method using microcrystalline cellulose-magnesium hydroxide

Microcrystalline cellulose (MCC), magnesium sulfate hexahydrate, and trisodium citrate were reacted in ammonia bath in an aqueous solution to prepare a MCC-magnesium hydroxide (MH) composite adsorbent, which was used to adsorb heavy metal Co(II) ion. The method of using MCC-MH to adsorb and remove Co(II) was studied under different pH values, adsorbent dosages, contact times, initial Co(II) ion concentrations, and temperatures. The optimal process parameters include an MCC-MH dosage of 2.5 mg/mL, a contact reaction equilibrium time of 50 min, a Co(II) solution pH of 6.0-8.0, an initial Co(II) concentration of 300 mg/L, and a temperature of 303 K. The removal rate of Co(II) solution by MCC-MH was as high as 97.67%, and the maximum adsorption capacity of MCC-MH reached 153.84 mg/g under these optimal conditions. The adsorption isotherm of Co(II) conformed to the Langmuir model, the kinetic data of Co(II) conformed to the pseudo-second-order kinetic model, and the adsorption of Co(II) by MCC-MH was a spontaneous endothermic reaction under the optimized conditions. Analytical studies showed that Co(II) adsorption on MCC-MH composites is affected by chemical adsorption and involves the influence of intraparticle diffusion to a certain extent.

Effective Disposal of Methylene Blue and Bactericidal Benefits of Using GO-Doped MnO2 Nanorods Synthesized through One-Pot Synthesis

Graphene oxide (GO)-doped MnO2 nanorods loaded with 2, 4, and 6% GO were synthesized via the chemical precipitation route at room temperature. The aim of this work was to determine the catalytic and bactericidal activities of prepared nanocomposites. Structural, optical, and morphological properties as well as elemental composition of samples were investigated with advanced techniques such as X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, UV-visible (vis) spectroscopy, photoluminescence (PL), energy-dispersive spectrometry (EDS), and high-resolution transmission electron microscopy (HR-TEM). XRD measurements confirmed the monoclinic structure of MnO2. Vibrational mode and rotational mode of functional groups (O-H, C=C, C-O, and Mn-O) were evaluated using FTIR results. Band gap energy and blueshift in the absorption spectra of MnO2 and GO-doped MnO2 were identified with UV-vis spectroscopy. Emission spectra were attained using PL spectroscopy, whereas elemental composition of prepared materials was recorded with scanning electron microscopy (SEM)-EDS. Moreover, HR-TEM micrographs of doped and undoped MnO2 revealed elongated nanorod-like structure. Efficient degradation of methylene blue enhanced the catalytic activity in the presence of a reducing agent (NaBH4); this was attributed to the implantation of GO on MnO2 nanorods. Furthermore, substantial inhibition areas were measured for Escherichia coli (EC) ranging 2.10-2.85 mm and 2.50-3.15 mm at decreased and increased levels for doped MnO2 nanorods and 3.05-4.25 mm and 4.20-5.15 mm for both attentions against SA, respectively. In silico molecular docking studies suggested the inhibition of FabH and DNA gyrase of E. coli and Staphylococcus aureus as a possible mechanism behind the bactericidal activity of MnO2 and MnO2-doped GO nanoparticles (NPs).