Study of Efficiency of Coupling Peptides with Gold Nanoparticles

Fluorescence spectroscopy was used to investigate the efficiency of coupling peptides to gold nanoparticles via 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride- N -hydroxysuccinimide (EDC-NHS). In this study, the effects of experiment conditions including the buffer solution (PBS, HEPES, Tris-HCl, and borate buffer solution), pH (6.5–9.0) and concentrations of buffer solution (10, 25, 40 and 50 mM), concentrations of NHS and EDC (from 0.2 M NHS-0.01 M EDC to 1.0 M NHS-0.5 M EDC), ratios of NHS to EDC (0, 0.5, 1.0, 2.0 and 2.5), and the coupling reaction time (4, 8, 12, 24 and 36 h) on the coupling efficiency were investigated and the optimized conditions were developed. These results indicated that the optimal experimental conditions were: pH 7.0 and 25 mM of the HEPES buffer solution, the concentrations ratios of NHS to EDC of 2:1 (0.4 M NHS-0.2 M EDC), and coupling reaction time of 24 h.