Introduction: Silver nanoparticles (AgNPs) have been widely recognized as effective antimicrobial agents for combating bacterial resistance. Methods: In this study, wastewater from Rosa canina oil distillation was utilized as a catalyst in the eco-friendly synthesis of AgNPs. As this waste has the potential to become enriched, ion-exchange column chromatography was used to prepare a polyphenol-enriched fraction from the wastewater. After evaluating the antioxidant activities (DPPH, FRAP, ORAC, NO scavenging, and comet assay) of fractions, the most potent antioxidant fraction was selected for the green synthesis of AgNPs. The AgNPs were synthesized using both chemical and green methods and optimized using Design-Expert® software based on particle size, polydispersity index (PDI), and zeta potential. Results: The optimized chemical (C-Ag-9) and green (G-Ag-1) synthesized nanoparticles displayed particle sizes of 84 and 52 nm, polydispersity indices (PDIs) of 1.9 and 1.4, and zeta potentials of -42.5 and -81 mV, respectively. The SEM-EDX analysis revealed weight percentages of 91.8% and 1.89% for the chemical (C-Ag-9) and green (G-Ag-1) synthesized AgNPs, respectively. The antibacterial activities of selected AgNPs were evaluated by determining inhibition zones on Pseudomonas aeruginosa media. When comparing two antibiotics, cefotaxime and chloramphenicol, as positive controls, G-Ag-1 results were significantly higher (p<0.0001) than C-Ag-9. Additionally, their ability to inhibit biofilm formation in Pseudomonas aeruginosa is significant when compared to ciprofloxacin. Discussion: These findings demonstrate that Rosa canina distillation wastewater constitutes a sustainable and valuable source of bioactive compounds for the green synthesis of AgNPs with enhanced antimicrobial efficacy. Conclusion: This wastewater can serve as an effective reducing agent. It would be a competitive alternative to chemical methods. These findings reveal the potential of valorized waste for the eco-friendly production of nanomaterials with promising antimicrobial and biomedical applications.
Introduction: Antimicrobial-resistant bacterial infections remain a significant public health concern, creating a need for new strategies to address this global problem. This study aimed to evaluate the antimicrobial activity of biogenic silver nanoparticles (Bio- AgNPs) synthesized using cell-free supernatant from the previously characterized probiotic Enterococcus durans strain against resistant bacterial strains. Methods: The antibacterial activity of Bio-AgNPs against vancomycin-resistant Enterococcus faecium (VRE) and methicillin-resistant Staphylococcus aureus (MRSA) was evaluated based on bacterial growth (minimum inhibitory concentration [MIC] using resazurin staining), viability (minimum bactericidal concentration [MBC] using CFU/mL), and time-kill assays (CFU/mL). Antibiofilm activity was evaluated using crystal violet staining to assess biofilm biomass and the XTT assay to assess metabolic activity. The viability of sessile biofilmforming cells was determined by CFU/mL. Bacterial membrane permeability was assessed using propidium iodide (PI) staining. Results: Bio-AgNPs exhibited inhibitory activity, with MIC values of 1.5 μg/mL for VRE E. faecium and 3.1 μg/mL for MRSA S. aureus. The MBC of Bio-AgNPs was twice the MIC for both strains. Bio-AgNPs demonstrated bactericidal activity, with a significant reduction in the number of surviving cells at concentrations equal to or greater than 0.15 μg/mL for E. faecium and 0.7 μg/mL for S. aureus. The time-kill assay showed a marked reduction in viable cells following exposure to Bio-AgNPs at 1× MIC after 12 h. Reductions of up to 53% in biofilm biomass and 92% in metabolic activity were observed. Bio-AgNPs also significantly reduced the number of viable sessile cells within biofilms. Discussion: Bio-AgNPs synthesized using cell-free supernatant from E. durans exhibited bactericidal activity against the MRSA and VRE strains evaluated, with low MIC and MBC values and a concentration-dependent effect on bacterial growth and survival. Fluorescence microscopy with PI suggested compromised bacterial membrane integrity following Bio- AgNP treatment, indicating that membrane disruption may contribute to their antibacterial activity. Bio-AgNPs also reduced biofilm biomass, metabolic activity, and the number of viable sessile cells. These findings support further investigation of Bio-AgNPs as biogenic antimicrobial candidates. Conclusion: These findings demonstrate that Bio-AgNPs synthesized using cell-free supernatant from E. durans exhibited bactericidal and antibiofilm activity against the resistant strains evaluated in vitro, supporting their potential as biogenic antimicrobial candidates for further investigation.
Introduction: This study reports the novel green synthesis of TiO2/HAp nanocomposites using Azadirachta indica (neem) leaf extract as a bio-reducing and stabilizing agent via the sol–gel method. The novelty lies in the concurrent use of a phytochemically rich botanical source to control nanoparticle nucleation and growth. Methods: TiO2/HAp nanocomposites were synthesized by two parallel routes: (i) conventional chemical synthesis using titanium isopropoxide, calcium hydroxide, and orthophosphoric acid, and (ii) plant-mediated green synthesis incorporating 20 mL of Azadirachta indica leaf extract (11.76% v/v) with 150 mg (0.88 mg/mL) of TiO2/HAp, followed by microwave irradiation (70 W, 30 min). The synthesized nanocomposites were characterized using XRD, FTIR spectroscopy, UV–Vis spectroscopy, SEM, and EDX analysis. Results: XRD analysis confirmed the formation of TiO2 (anatase, JCPDS 21-1272) and hexagonal hydroxyapatite (JCPDS 09-0432) phases, with average crystallite sizes of 36.33 nm (chemically synthesized) and 40.44 nm (green-synthesized). FTIR spectroscopy confirmed characteristic Ti–O, PO4³⁻, and O–H functional groups, along with phytochemical signatures in the green-synthesized sample. SEM analysis revealed a uniform, rod-like morphology with minimal aggregation. The DPPH radical scavenging assay demonstrated significantly higher antioxidant activity for the green-synthesized nanocomposites (80.12 ± 1.43% at 500 μg/mL) compared to the chemically synthesized counterpart. Discussion: The formation of TiO2/HAp nanocomposites has been confirmed by FTIR spectra, and the presence of phytochemical functional groups was identified in the green-synthesized sample, consistent with surface functionalization. The green-synthesized nanocomposites have much better antioxidant properties because they contain bioactive phytochemicals from Azadirachta indica that are retained on the surface. Conclusion: The green-synthesized TiO2/HAp nanocomposites demonstrated higher antioxidant activity, consistent with a contribution from phytochemicals associated with the green-synthesis route; direct quantitative confirmation of surface-bound phytochemical loading remains a priority for future work. These results provide a preliminary basis for further investigation of these materials for antioxidant and surface-functional applications, while biomedical relevance requires additional cytotoxicity, antibacterial, and application-specific validation.
Introduction: The objective of this research is to produce electrospun polyvinylidene fluoride (PVDF) nanofibers combined with Titanium Dioxide (TiO2), aiming to enhance the piezoelectric properties and fiber dimensions of PVDF nanofibers by incorporating TiO2 nanoparticles. Methods: PVDF nanofibers are electrospun directly with a decreased diameter by employing Tetrabutylammonium chloride (TBAC) in conjunction with TiO2. The effects of TiO2 nanoparticles on the diameters, crystalline phases, and piezoelectric properties of PVDF and PVDF/TBAC nanofibers are comprehensively analyzed. results: The findings indicate that the electrospun PVDF/TiO2 nanofibers exhibit exceptional crystallinity, remarkable β phase content (F(β)), and superior electrical outputs. Results: The findings indicate that the electrospun PVDF/TBAC/TiO2 nanofibers exhibit exceptional crystallinity, remarkable β phase content (F(β)), and superior electrical outputs. Discussion: The improvements can be credited to the reduced fiber diameters, increased F(β), and an expanded contact surface area. Conclusion: We posit that this research can serve as a valuable reference for the preparation, characterization, and application of PVDF/TiO2 nanofibers in energy harvesting.
Introduction: Water contamination by organic dyes poses a severe environmental threat, affecting aquatic ecosystems and human health due to their unreactive nature and resistance to conventional treatment methods. In this study, bismuth oxide nanoparticles (Bi2O3 NPs) were biogenically synthesized using Olea europaea (olive) leaf extract as the main source of natural reducing and capping agents. Methods: Biosynthesized Bi2O3 NPs were characterized with different analytical techniques, such as UV-Visible, FT-IR, XRD, and SEM. Photocatalytic degradation of methylene blue was assessed under various optimized conditions, including catalyst concentration, contact time, temperature, and pH. Catalyst reusability was also evaluated over five consecutive cycles. Results: The analysis confirmed the formation of crystalline Bi2O3 NPs with flake-like morphology, with a mean diameter of 41.20 nm and a crystallite size of 18.30 nm. The difference in their sizes confirmed the multicore nature of Bi2O3 NPs. The catalytic degradation of methylene blue (MB) under different optimization parameters demonstrated a maximum 82% degradation with a 0.01782 min⁸¹ k value, following pseudo-first-order kinetics with a 0.99 regression coefficient (R²). Reusability tests revealed an 11% decrease in degradation efficiency after five cycles due to reduced availability of active sites. Discussion: The regeneration and sustainability of plant-mediated nanocatalysts were observed experimentally, and an 11% decrease in the degradation rate was highlighted after five cycles due to reduced availability of active sites. Conclusion: The results of this study affirm that the green synthesis route offers a costeffective, eco-friendly, and efficient way to treat toxic environmental pollutants safely by using renewable plant extracts, mild reaction conditions, and good catalyst reusability.
