DNA-binding, antioxidant, H₂O₂ sensing and photocatalytic properties of biogenic silver nanoparticles using Ageratum conyzoides L. leaf extract

Green nanotechnology is gaining widespread interest owing to the elimination of harmful reagents and offers a cost-effective synthesis of expected products. In the present study, silver nanoparticles (AgNPs) were synthesized from Ageratum conyzoides leaf extract (ACLE). UV-visible spectrophotometry showing a characteristic SPR peak at 443 nm verified the phytosynthesis of AC-AgNPs. The FTIR spectrum was examined to identify the efficient functional molecules responsible for the reduction of Ag⁺ to metallic silver (Ag⁰). SEM, TEM and XRD illustrated the formation of crystalline and spherical NPs with a size range of 14-48 nm. EDX data showed the presence of elemental silver with an energy peak at 3 eV. CT-DNA interaction with AC-AgNPs was investigated and the UV absorption spectra revealed a bathochromic effect indicating groove binding. AC-AgNPs showed a strong antioxidant property in a concentration-dependent manner when analyzed by DPPH and ABTS radical scavenging assay. AC-AgNPs were investigated as a SPR-based H₂O₂ sensor, which can provide promising opportunities in medical and environmental fields to detect reactive oxygen species such as H₂O₂. The catalytic effectiveness of phytosynthesized NPs was also examined within 2 h of exposure for methylene blue degradation under sunlight. There is thus a reasonable potential application of green synthesized AC-AgNPs for the degradation of hazardous synthetic dyes.