Synthesis of thiolated chlorogenic acid-capped silver nanoparticles for the effective dual action towards antimicrobial and anticancer therapy

Chlorogenic acid (CGA) was thiolated using Traut's reagent. Then, thiolated chlorogenic acid (CAT) functionalized on the silver nanoparticles (AgNPs). The resulting CAT-functionalized silver nanoparticles (CAT-AgNPs) have higher stability with a uniform spherical shape compared to naked AgNPs. The average particle size is 10 nm, as revealed by transmission electron microscopy (TEM). The antimicrobial activity was higher against both gram-positive and gram-negative bacteria of spherically stable nanoparticles evaluated by the disk diffusion method. Minimal inhibitory concentration (MIC) values for CAT-AgNPs were 130 mu g/ml for Staphylococcus aureus and 150 mu g/ml for Escherichia coli. Cytotoxicity studies showed that the CAT-AgNPs show maximum activity against MCF-07 cell lines with an IC50 value of 20 ng/ml. Compared to traditional noncovalent interactions, the Ag-S covalent linkage of CAT with AgNPs helped in highly stable capping. The prepared CAT-AgNPs show anticancer and antibacterial activities, thus providing an efficient antimicrobial nano-drug carrier. Nanoparticles with a dual-mode of action help in preventing fouling of nanocarriers while delivering drugs to targeted cells, opening up many applications in nanobiotechnology and nanomedicine.