Antioxidant Activities of Photoinduced Phycogenic Silver Nanoparticles and Their Potential Applications

Eco-friendly green synthesis of AgNPs from Elaeocarpus serratus fruit extract: potential to antibacterial, antioxidant, cytotoxic effects of colon cancerous cells (HT-29) and its toxicity assessments of marine microcrustacean Artemia nauplii

BACKGROUND

The present work demonstrated the green synthesis and characterization of silver nanoparticles (AgNPs) utilizing Elaeocarpus serratus fruit extract. The study examined the effectiveness of phytocompounds in fruit extract in reducing Ag+ to Ag° ions.

METHODS

The water-soluble biobased substance production from silver ions to AgNPs in 45 min at room temperature. Surface plasmon resonance (SPR) peak was seen in the UV-visible absorption spectrum of the biologically altered response mixture. Examination with X-ray diffraction (XRD) showed that AgNPs are strong and have a face-centered cubic shape. Scanning electron microscope (SEM) investigation proved the production of AgNPs in a cuboidal shape.

RESULTS

The AgNPs demonstrated remarkable antibacterial activity and a potent capacity to neutralize DPPH (2,2-Diphenyl-1-picrylhydrazyl) radicals. The highest growth inhibition was found for E. serratus against S. dysenteriae (18.5 ± 1.0 mm) and S. aureus (18 ± 1.2 mm). These nanoparticles exhibited robust antiradical efficacy even at low concentrations. The AgNPs additionally exhibited cytotoxic effects on (HT-29) human colon adenocarcinoma cancer cells. The MTT assay (3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) indicated an inhibitory concentration (IC50) value of 49.1 ± 2.33 µg/mL for AgNPs, contrasting with the untreated cells of the negative control. The biotoxicity assessment using A. salina displayed mortality rates ranging from 8 to 69.33%, attributable to the E. serratus synthesized AgNPs.

CONCLUSIONS

In our results concluded that simply first-hand information on that E. serattus fruit extract synthesized AgNPs were efficiently synthesized without the addition of any hazardous substances, and that they may be a strong antibacterial, antioxidant, and potential cytotoxic effects for the treatment of colon carcinoma cell lines.

Blue Laser-Activated Silver Nanoparticles from Grape Seed Extract for Photodynamic Antimicrobial Therapy Against Escherichia coli and Staphylococcus aureus

Introduction: Living organisms, particularly humans, frequently encounter microorganisms like bacteria, fungi, and viruses in their surroundings. Silver nanoparticles are widely used in biomedical devices due to their antibacterial, antifungal, and antiviral properties. The study evaluates the efficacy of blue laser and silver nanoparticles from grape seed extract (AgNPs-GSE) in reducing gram-negative Escherichia coli and gram-positive Staphylococcus aureus bacteria causing infections. Methods: The sample consisted of four groups: a control without laser irradiation (T0), E. coli samples (A1 and A2) irradiated with a 405 nm diode laser at different times and concentrations of silver nanoparticles, and S. aureus samples (A3 and A4) irradiated with a 405 nm diode laser at different times and concentrations. Bacteria in groups A2 and A4 were treated with a photosensitizer (PS) made from grape seed extracts, incubated for 10 minutes, and then irradiated for 90, 120, 150, and 180 seconds. The samples were cultured on Tryptic Soy Agar (TSA) media, incubated at 37 °C, counted by using a Quebec colony counter, and analyzed using ANOVA and Tukey tests with a significance level of P<0.05. Results: The study found that 10 µl of AgNPs-GSE, when combined with exposure to a blue laser at 405 nm and a dose of 3.44 J/cm2, can effectively photoinactivate E. coli and S. aureus bacteria. The addition of AgNPs-GSE to E. coli bacteria led to a significant reduction in their viability, with a reduction of 73.93%, 80.96%, and 83.80%, respectively. Similarly, when S. aureus bacteria were irradiated for 180 seconds by adding 1 mM, 1.5 mM, and 2 mM AgNPs-GSE, bacterial viability was reduced by 70.87%, 78.04%, and 87.01%, respectively. Conclusion: The findings from the present study indicate that at an energy density of 3.44 J/cm2, it was possible to inactivate E. coli by 83.80% and S. aureus by 87.01%.

Silver/Graphene Oxide Nanostructured Coatings for Modulating the Microbial Susceptibility of Fixation Devices Used in Knee Surgery

Exploring silver-based and carbon-based nanomaterials' excellent intrinsic antipathogenic effects represents an attractive alternative for fabricating anti-infective formulations. Using chemical synthesis protocols, stearate-conjugated silver (Ag@C18) nanoparticles and graphene oxide nanosheets (nGOs) were herein obtained and investigated in terms of composition and microstructure. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) characterizations revealed the formation of nanomaterials with desirable physical properties, while X-ray diffraction (XRD) analyses confirmed the high purity of synthesized nanomaterials. Further, laser-processed Ag@C18-nGO coatings were developed, optimized, and evaluated in terms of biological and microbiological outcomes. The highly biocompatible Ag@C18-nGO nanostructured coatings proved suitable candidates for the local modulation of biofilm-associated periprosthetic infections.