Synthesis and properties of silver nanoparticles-antibiotic conjugates for study of antibiotic-resistance mechanisms

Abstract

The spread of antibiotic-resistant pathogens poses a global threat to public health, food security, and sustainable development. The design of new scientific tools based on nanoparticle (NP) surface plasmon resonance detection is relevant for the study of antibiotic resistance mechanisms. Specific aim of the research was to obtain stable conjugates of silver NPs (AgNps) with antibiotic for the study of antibiotic-resistance mechanisms. NPs with similar size and shape but with antibiotics as surface stabilizing agents were synthesized. We obtained stable conjugates of AgNPs with teicoplanin, vancomycin, chloramphenicol, cefotaxime, cefuroxime, ceftriaxone, ampicillin, and novobiocin. NPs with penicillin, cefazolin, amikacin, apramycin, kanamycin, gentamicin, and erythromycin were not stable and aggregated immediately after synthesis. The maximums of the surface plasmon resonance absorbance of all conjugates were at a wavelength of 400 ± 7 nm. Transmission electron microscopy results showed disperse NPs spherical in shapes with size from 2 to 20 nm with average diameters of 10 to 11 nm for all obtaining conjugates. Dialysis was the most appropriate procedure for AgNPs-antibiotic conjugates purification, whereas ultracentrifugation at 100,000 g lead to aggregations of NPs and loss of optical nano-properties. The optimal temperature for conjugates storage is 4°C and pH 6 to 8. AgNPs-antibiotic conjugates exhibited stability under different conditions (temperature, pH, and biological mediums). These features and strong optical and antibacterial properties make AgNPs-antibiotic conjugates as attractive tools for the study of antibiotic resistance mechanisms.