Green synthesis of metallic nanoparticles using hollyhock (Alcea rosea) and calendula (Calendula officinalis) plant extracts and investigation of their applications

In this thesis, seed and flower water extracts of hollyhock (Alcea rosea) and calendula (Calendula officinalis) plants were obtained and green synthesis of Ag, Cu and AgCu nanoparticles was carried out with these extracts. The effects of extract concentration, metal ion concentration, temperature and duration on synthesis were investigated. SPR peaks between wavelengths of 400-450 nm in UV-Vis spectra have proven the formation of nanoparticles. With FTIR analysis, phytochemicals were found to play a role in nanoparticle formation and stabilization; images of nanoparticles were obtained by TEM, and elemental contents were determined by EDX analysis. Antioxidant activities were examined by DPPH method; activity was above 75% for AgNPs and AgCuNPs; for CuNPs, it was determined to be between 37-50%. It has been determined that AgNPs and AgCuNPs showed antibacterial activity against E. coli ATCC 25922 and S. aureus ATCC 25923 bacteria by forming inhibition zones with a diameter of 16-26 mm by agar-well method, but CuNPs did not show activity. The usability of the synthesized nanoparticles as support materials in enzyme immobilization was investigated; for this purpose, the lysozyme enzyme was covalently immobilized by EDC/NHS chemistry and its activity was measured. It is thought that the nanoparticles produced in this study have the potential to find applications in many other fields such as environment, biotechnology, and medicine.