RESUMO
The 13 nm gold nanoparticles ( AuNPs ) were synthesized through the reduction of HAuCl4 by sodium citrate and the glutathione was assembled on the AuNPs. Under the experiment conditions, glutathione-modified AuNPs ( GSH-AuNPs ) with negative charge presented a wine red color owing to the electrostatic repulsion between nanoparticals. Upon the addition of neurogenin 3 ( ngn3 ) peptide, the aggregation of GSH-AuNPs was induced by ngn3 peptide under a certain concentration of salt. The color of AuNPs solution changed from red to blue as a function of the ngn3 peptide concentration. Thus, a rapid detection method for ngn3 peptide using GSH-AuNPs as colorimetric probe was established. The optimal experiment conditions were equilibrium time=10 min, pH=6. 0, CNaCl=100 mmol/L. Under the optimum conditions, the assay showed a linear response range of 20-300 μg/L for the peptide with a detection limit being 8 μg/L and exhibited excellent selectivity for ngn3 peptide.