Investigation of silver nanoparticles in biomedical applications obtained from avocadoplant peel extract using green synthesis

The usability of silver nanoparticles (AgNPs) in biomedical applications depends on their physicochemical properties, biocompatibility, and effectiveness in biological systems. Although many plant species and parts are used in the green synthesis of functional and biocompatible AgNPs, the use of avocado peel as a reducing agent is relatively low. In this study, an environmentally friendly, economical, and straightforward synthesis method was employed to produce AgNPs with a size of 12.0 ± 2.0 nm, using avocado peel, which is typically considered waste. Silver nanoparticles were utilized as sensors in a colorimetric sensor system due to their localized surface plasmon resonance (LSPR) properties, and their interactions with heavy metal ions were investigated. The system specifically responded to the Hg²⁺ ion, with resulting color changes observed both with the naked eye and via UV-Visible spectrophotometry. The limits of detection (LOD) and quantification (LOQ) of the system were calculated to be 0.27 μM and 0.81 μM, respectively. The colorimetric sensor system was tested in real-world applications, yielding recovery values of 83.75% in wastewater, 97.5% in drinking water, and 103.75% in both seawater and tap water. In addition to its colorimetric properties, the antibacterial and anticancer effects of the synthesized AgNPs were examined. The antibacterial properties were assessed using gram-positive Staphylococcus aureus and gram-negative Escherichia coli bacteria. Zone formations were evaluated in response to different AgNP concentrations using the disk diffusion method, with results ranging from 1.5 to 11 mm for Staphylococcus aureus and 1 to 9 mm for Escherichia coli. Cytotoxicity tests (MTT) were performed on Beas-2B (normal lung bronchial epithelial) and N417 (small cell lung cancer) cell lines to evaluate the potential of AgNPs in anticancer applications. Cell proliferation and survival (IC50) values were calculated based on AgNP solvent combinations and concentration variations. For AgNP-PBS, AgNP-Medium, and AgNP-BSA combinations, the IC50 values were found to be 224.6 ppm, 146.7 ppm, and 201.3 ppm in Beas-2B cells; and 246.7 ppm, 290.7 ppm, and 7.460e-61 ppm (uncertain) in N417 cells, respectively. The results obtained provide hope for the diagnosis and treatment of diseases, highlighting the potential biological properties of AgNPs synthesized with avocado peel extract and their effectiveness even at low concentrations.