科研之友
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摘要
Gold nanoparticles (NGs) were modified by the aptamer (ssDNA) to prepare a NGssDNA probe for As3+. In pH 8.0 HEPES buffer solution containing 50 mmol L-1 NaCl, rhodamine 6G (Rh6G) molecules adsorbed on the NGssDNA sol substrate exhibited a strong surface-enhanced Raman scattering peak (SERS) at 1358 cm(-1). Upon addition of As3+, it reacts with the NGssDNA probe to form a stable As-ssDNA complex and release NGs that were aggregated to the NG aggregates (NGAs) as a substrate, in which Rh6G SERS activity is very weak. With the increase of As3+ concentration, the SERS peak decreased at 1358 cm(-1) due to more NGAs forming. The decreased SERS intensity responds linearly with the concentration of As3+ over 0.288-23.04 ng mL(-1), with a detection limit of 0.1 ng mL(-1).
