Research Spectrum: Research & Advances in Biotechnology

Green-synthesized quantum dots from quercus brantii for infected polymicrobial wound healing: mechanisms and biocompatibility

Thu, 27 Aug 2026 00:00:00 +0000

Background: The rise of antimicrobial resistance (AMR) has created an urgent need for alternative therapies, particularly against biofilm-driven polymicrobial wound infections. Although green-synthesized nanoparticles have emerged as promising candidates, many studies lack rigorous validation of their quantum properties, fail to clarify mechanisms of action, and omit essential cytotoxicity profiling in human cells.

Objective: To synthesize silver (Ag), copper (Cu), and zinc oxide (ZnO) quantum dots (QDs) using Quercus brantii acorn extract, confirm quantum confinement effects, and evaluate their antimicrobial efficacy, mechanistic basis, and biosafety in a clinically relevant murine wound model.

Methods: QDs were synthesized via a standardized hydrothermal approach. Quantum confinement was verified using photoluminescence (PL) spectroscopy and Tauc plot analysis. Antimicrobial activity was tested against multidrug-resistant (MDR) clinical isolates of Pseudomonasaeruginosa, methicillin-resistant Staphylococcus aureus (MRSA), Acinetobacter baumannii, and Klebsiella pneumoniae. To differentiate oxidative stress from chemical artifacts, we employed non-thiol reactive oxygen species (ROS) scavengers (Trolox, Mannitol) and electron paramagnetic resonance (EPR). Cytotoxicity was assessed in human keratinocytes (HaCaT) and dermal fibroblasts (HDF). In vivo efficacy was evaluated in a murine excisional wound model infected with a polymicrobial consortium, tracking pathogen-specific clearance. Hydrogel rheology and stability were also characterized.

Results: Monodispersed, crystalline QDs with evidence consistent with quantum confinement were obtained (Ag-QDs: 7.2 ± 1.5 nm; apparent bandgap: 2.85 eV). Ag-QDs showed strong antimicrobial activity (MIC: 4.5–18.1 μg/ mL) and biofilm inhibition (up to 85% at ½×MIC). Mechanistic experiments, including EPR and ROS-scavenger assays, supported ROS-associated oxidative stress as a major contributor to bacterial killing under the tested conditions. Ag-QDs exhibited bactericidal activity at concentrations that were non-toxic to human skin cells in the employed assay (Selectivity Index for MRSA: 18.9). In vivo, topical application of an Ag-QD hydrogel (shear-thinning) accelerated wound closure to 95.3% by Day 14 (comparable to uninfected controls) and reduced the total bacterial burden by 4.2 log₁₀ CFU/g; all four pathogens were below the detection limit at the study endpoint. No overt systemic toxicity was observed based on the assessed biomarkers. Resistance development in serial passage assays was limited (2-fold MIC increase after 30 passages), noting that longer-term polymicrobial studies are required to fully evaluate resistance
evolution.

Conclusion: Q. brantii-mediated Ag-QDs are a promising green-synthesized nanomaterial with physicochemical characteristics consistent with quantum-dot behavior and notable antimicrobial and antibiofilm activity against MDR polymicrobial communities. In a preclinical murine wound model, topical Ag-QD hydrogel treatment was associated with accelerated wound closure and marked reductions in bacterial burden, alongside a favorable preliminary biosafety profile based on the endpoints assessed. Further studies are warranted to validate efficacy in clinically relevant chronic wound settings (e.g., diabetic models), to expand long-term toxicology, and to clarify resistance evolution and mechanistic pathways in polymicrobial systems.

Green synthesis of ZnO nanoparticles using Citrus sinensis peel: optimizing volume ratios for enhanced antibacterial and banana preservation activities

Fri, 21 Aug 2026 00:00:00 +0000

This study explores the green synthesis of zinc oxide nanoparticles (ZnO NPs) using aqueous extract of Citrus sinensis peel. C. sinensis peel is bioactive, phytochemical rich and readily available agro-waste. The aim of this study was to investigate the effects of varying the volume ratio of zinc nitrate precursor to peel extract (1:1, 1:2, and 2:1) on the physicochemical properties, antibacterial activity, and preservative efficacy of biosynthesized ZnO NPs. Structural analysis by X-ray diffraction (XRD) confirmed the formation of crystalline hexagonal wurtzite ZnO NPs across all synthesis ratios. The 2:1 ratio exhibiting superior crystallinity and larger crystallite size (24.2 nm). Fourier transform infrared (FTIR) spectra identified zinc-oxygen bonds and confirmed the role of peel-derived biomolecules in NP capping and stabilization. Ultraviolet-visible (UV-vis) spectroscopy revealed strong absorbance peaks at approximately 370 nm, characteristic of ZnO NPs, with the 2:1 sample exhibiting the highest optical absorption. Scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS) and transmission electron microscopy (TEM) revealed morphological transitions from aggregated particles to elongated rod-like structures with increasing zinc nitrate ratio, confirming elemental composition of zinc and oxygen. Antibacterial activity testing using disc diffusion methods against Gram-positive and Gram-negative bacteria revealed concentration-dependent inhibition, with ZnO synthesized at a 2:1 ratio providing the most potent antibacterial activity. Furthermore, chitosan-based nano-coating incorporated with ZnO NPs significantly reduced weight loss in banana fruit preservation trials, indicating enhanced shelf life. The 2:1 ratio coating is showing the best preservation performance. This study underscores the critical role of precursor ratio in tailoring NP size, morphology, crystallinity, and bioactivity. The findings demonstrate that green-synthesized ZnO NPs using C. sinensis peel extract represent promising, sustainable nanomaterials for antibacterial applications and food preservation, with minimized environmental impact.

Identification of novel therapeutic targets for ovarian hypofunction through hormonal pathway regulation

Yunqi Wang, Lijuan Xiang, Rui Zhao, Xiao-Juan Zhang, Yang Chen — Thu, 14 May 2026 00:00:00 +0000

Ovarian hypofunction (OH) is a multifactorial endocrine disorder characterized by impaired folliculogenesis, hypoestrogenism, and subfertility, affecting an estimated 10–12% of reproductive-aged women worldwide and up to 1% of women under 40 years of age. Current interventions, including hormone replacement therapy (HRT), gonadotropin stimulation, and assisted reproductive technologies (ART), remain largely symptomatic, carry safety concerns, and fail to restore intrinsic ovarian activity. To address this unmet need, we employed an integrative computational strategy combining systems-level biological insights with immunoinformatics approaches to identify and evaluate a multi-epitope peptide candidate targeting the follicle-stimulating hormone receptor (FSHR). Seven FSHR-derived peptides with high predicted immunogenic potential were identified, validated for non-allergenicity and non-toxicity, and fused with flexible linkers into a 62-amino-acid construct. Physicochemical analysis indicated stability (instability index 38.80), thermostability (aliphatic index 89.68), hydrophilicity (GRAVY −0.365), and favorable
solubility (Protein-Sol 0.584 compared with an E. coli average of 0.45). Codon optimization improved the codon adaptation index from 0.64 to 0.90 and reduced GC content from 63.98% to 53.23%, suggesting high expression potential in E. coli. Molecular docking with TLR2 yielded a favorable docking score (−296), supported by extensive hydrogen bonding and hydrophobic interactions. Long-timescale molecular dynamics simulations (500 ns) supported structural stability, with RMSD plateauing at approximately 0.3 nm, a compact radius of gyration (2.52–2.55 nm), and a persistent hydrogen-bond network (1250–1400 bonds). In silico immune simulations suggested balanced humoral and cellular immune responses, characterized by early IgM production, class switching to IgG, IL-2–associated T-cell expansion, and immune memory formation. Overall, this computational study identifies a structurally stable and immunologically promising peptide candidate for ovarian hypofunction, providing a rational
basis for future experimental validation.

Preparation, characterization, and evaluation of chitosan-thymol nanoparticles for antibacterial and antibiofilm activities against catheter-associated uropathogenic Escherichia coli

Fri, 21 Aug 2026 00:00:00 +0000

Uropathogenic Escherichia coli (UPEC) is a major cause of urinary tract infections (UTIs) and is capable of forming biofilms on inert surfaces, contributing to persistent and recurrent infections. Given the limitations of conventional antibiotics, alternative strategies are needed to control multidrug-resistant (MDR) UPEC. This study aimed to evaluate the antibacterial and antibiofilm effects of thymol-loaded chitosan nanoparticles (TLCNPs) against MDR UPEC isolates urinary catheters. TLCNPs were prepared using the ionotropic gelation method and characterized by scanning electron microscopy (SEM), dynamic light scattering (DLS), and Fourier-transform infrared spectroscopy (FTIR). The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined using the broth microdilution method. Antibiofilm activity was assessed by the microtiter plate crystal violet assay. The relative expression of fimA and fimH genes was evaluated using real-time PCR. Cytotoxicity was assessed by the MTT assay on a human bladder carcinoma cell line (EJ138). The results showed that TLCNPs exhibited antibacterial activity against MDR UPEC isolates, with MIC and MBC values of 625 μg/mL. Biofilm formation was reduced by up to 76.2 ± 0.6% at ½ MIC concentration. Although a decrease in the relative expression of fimA and fimH genes was observed following treatment with TLCNPs, these changes were not statistically significant. Cytotoxicity assays indicated that more than 70% of EJ138 cells remained viable after 24 h, and over 50% after 48 h at ½ MIC. Overall, this study evaluated the antibacterial, antibiofilm, and preliminary safety profile of thymol-loaded chitosan nanoparticles against MDR UPEC, providing experimental data for their further investigation as a potential adjunct approach for biofilm-associated UTIs.

Phyto mediated synthesis of copper oxide nanoparticles with Zingiber officinale: comprehensive bioactivity assessment against bacterial pathogens, cancer, and viruses

Tue, 18 Aug 2026 00:00:00 +0000

This work investigated the capacity of Zingiber officinale extract to synthesize copper oxide nanoparticles. Z. officinale extract is rich in diverse phytochemical constituents, as confirmed by GC–MS analysis. The synthesized CuO NPs were characterized using TEM, FTIR, XRD, SEM, and EDX analyses. CuO NPs exhibited antibacterial efficacy against various bacterial strains. The DPPH methodology was employed to evaluate the free radical scavenging capacity, yielding an IC₅₀ value of 244.5 μg/mL. The CuO NPs exhibited pronounced antibiofilm activity at 100 μg/mL, reducing biofilm formation by S. aureus (MRSA) and E. coli by 70.93% and 67.3%, respectively. In addition, they demonstrated substantial antidiabetic potential, inhibiting α-amylase and α-glucosidase by up to 90% and 84% at 1000 μg/mL, with corresponding IC₅₀ values of 46.42 μg/mL and 38.9 μg/mL, respectively. Furthermore, CuO NPs exhibited low toxicity toward Vero cells, with an IC₅₀ of 261 μg/mL and showed potential anticancer activity against the carcinoma cell lines CaCo2 and McF7, with IC₅₀ values of 84.4 and 168 μg/mL, respectively. At 125 μg/mL, CuO NPs inhibited HAV and HSV-1 by 37% and 41.1%, respectively. These multifaceted bioactivities highlight the potential of Z. officinale–mediated CuO NPs as promising candidates for therapeutic and biomedical applications.