AgNPls were synthesized by following the reported procedure using the chemical
reduction process [12]. Sodium borohydride and methyl cellulose solution were used as the
reducing agent and stabilizer, respectively. The actual shapes, particle, and size distributions
of the AgNPls with nominal mean diameters of 30 nm were studied by TEM. For the
modification step, the GSH-Cys-AgNPls solution was prepared via self-assembly of the
aminothiol on the AgNPls surface. Briefly, 1000 µL of 50 µM GSH and 5000 µL of 50 µM
Cys were added into 44 mL of 0.1 mM AgNPls solution and stirred for about 2 h to ensure a
complete self-assembly of the GSH and Cys onto the surface of AgNPls. After that, the
characterization of the unmodified and modified AgNPls were conducted using UV–Vis and
FTIR spectroscopy.