Abstract: Biotinylated silver nanoparticles(Bio-AgNPs) were successfully prepared using oligonucelotide as coupling molecules. The resulted bio-AgNPs could be used for visual detection for protein arrays by a catalytical reaction with hydroquinone/AgNO3. To probe the feasibility of visual detection, human IgG was used as a model protein sample to be immobilized on the glass slides and bio-AgNPs were employed to couple with the protein via stripavaidin labeled anti-human IgG. The results show that the linear relationship of protein concentration is between 160 fg and 100 pg and the limit of detection is 160 fg(S/N=3). Compared with the method using SA-labeled gold nanoparticle or silver enhancement, the sensitivity of this method is increased about 40 fold. The presented method shows that its advantages including high sensitivity, stability and rapidity.

Key words: Biotinylated silver nanoparticle(Bio-AgNPs), Hydroquinone/AgNO3, Micro-protein detection, Protein chip