Advanced biomaterial agent from chitosan/poloxamer 407-based thermosensitive hydrogen containing biosynthesized silver nanoparticles using Eucalyptus camaldulensis leaf extract.

CONTEXT: The emergence of multidrug-resistant (MDR) pathogens poses a significant challenge for global public health systems, increasing hospital morbidity and mortality and prolonged hospitalization. OBJECTIVE: We evaluated the antimicrobial activity of a thermosensitive hydrogel containing bio-synthesized silver nanoparticles (bio-AgNPs) based on chitosan/poloxamer 407 using a leaf extract of Eucalyptus calmadulensis. RESULTS: The thermosensitive hydrogel was prepared by a cold method after mixing the ingredients and left at 4°C overnight to ensure the complete solubilization of poloxamer 407. The stability of the hydrogel formulation was evaluated at room temperature for 3 months, and the absorption peak (420 nm) of the NPs remained unchanged. The hydrogel formulation demonstrated rapid gelation under physiological conditions, excellent water retention (85%), and broad-spectrum antimicrobial activity against MDR clinical isolates and ATCC strains. In this regard, minimum inhibitory concentration and minimum microbial concentration values of the bio-AgNPs ranged from 2-8 µg/mL to 8-128 µg/mL, respectively. Formulation at concentrations <64 µg/mL showed no cytotoxic effect on human-derived macrophages (THP-1 cells) with no induction of inflammation. CONCLUSIONS: The formulated hydrogel could be used in biomedical applications as it possesses a broad antimicrobial spectrum and anti-inflammatory properties without toxic effects on human cells.

Poly (vinyl alcohol) copolymerized with xanthan gum/hypromellose/sodium carboxymethyl cellulose dermal dressings functionalized with biogenic nanostructured materials for antibacterial and wound healing application.

Effective treatment of infected wounds requires a comprehensive wound dressing with a combination of antibacterial, antioxidative, and anti-inflammatory effects. Biodegradable wound dressings incorporating nanostructured material were developed using polyvinyl alcohol with xanthan gum, hypromellose, or sodium carboxymethyl cellulose and extensively evaluated for antibacterial and wound healing efficacy. Synthesized silver nanoparticles and wound dressings displayed λmax at 420 nm with zeta potential ≈ - 35 mV. Significant growth inhibition with >99 % reduction in CFU/ml (p < 0.05) against important wound pathogens including Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, Staphylococcus epidermidis, and Candida albicans were observed. Within 1 h of treatment, hypromellose nanocomposite demonstrated excellent bactericidal effects with a 99.9 % of reduction in growth. In addition, wound dressings demonstrated inhibitory activities against free radical scavengers. Wound dressings demonstrated a significant reduction in the inflammatory response in RAW 264.7 macrophages (p < 0.001). Ex-vivo diffusion demonstrated zero-order release and steady-state flux between 0.1571-0.2295 µg/ml/cm2h with 0.124-0.144 permeability coefficient after 10 h. Usage in animals further confirmed that the hypromellose nanocomposite accelerated the wound healing process with biocompatibility. The results suggested that hybrid biodegradable dressings can be effectively applied to treat infected wounds and attenuate inflammatory responses.

Antibacterial-coated silk surgical sutures by ex situ deposition of silver nanoparticles synthesized with Eucalyptus camaldulensis eradicates infections.

Surgical site infection arising from microbial contamination of surgical wounds is a major cause of surgical complications and prolong hospital stay. In this study, silver nanoparticles (AgNPs) biosynthesized using Eucalyptus camaldulensis extract were deposited on silk surgical sutures by ex situ method. Adherence of AgNPs to the surface of sutures was observed, with significantly reduced surface roughness (323.7 ± 16.64 nm), compared with uncoated sutures (469.3 ± 7.31 nm) (P < .001). Elasticity of AgNPs-coated (13 ± 1.485%) and uncoated (8 ± 0.728%) sutures was also significantly different (P < .05). Quantification of AgNPs demonstrated release of 3.88, 5.33, 5.44, 6.14% on day 1, 3, 5, 7, respectively from total Ag+ concentration (6.14 ± 0.14 µg/mL). The coated sutures produced a strong bacteriostatic effect on Staphylococcus aureus, an important wound pathogen with approximately 99% reduction in growth. In contrast, bactericidal effects were observed with Gram-negative pathogens including Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. Cytocompatibility tested on human keratinocyte cells exhibited approximately 80% cell viability. The coated sutures revealed stable antibacterial properties up to 12 weeks. This work suggested the potency of AgNPs-coated sutures as a suitable biocompatible medical device for the management of surgical site infections.