Colorimetric detection of thiol-containing amino acids using gold nanoparticles.
This paper reports findings of an investigation of the unusual colorimetric change of gold nanoparticles in the presence of thiol-containing amino acids such as homocysteine, cysteine and glutathione. The colorimetric change for homocysteine exhibits a rate that is about two orders of magnitude higher than that for cysteine, and at least five orders of magnitude higher than that for glutathione. The reactivity is effectively reduced or suppressed by the coexistence of either cysteine or glutathione. It is believed that the reactivity involves encapsulation of the particles by the thiol-containing amino acids which is followed by crosslinking at the encapsulating shells. In comparison with cysteine and glutathione, homocysteine has a slower encapsulating rate but a faster crosslinking rate. Implications of the findings of the interfacial encapsulation and crosslinking reactivities of gold nanoparticles to potential nanoparticle-enhanced analytical detection of thiol-containing amino acids are also briefly discussed.
Zhang
Felicia X
FX
Department of Chemistry, State University of New York at Binghamton, 13902, USA.
Han
Li
L
Israel
Lisa B
LB
Daras
Jason G
JG
Maye
Mathew M
MM
Ly
Nam K
NK
Zhong
Chuan-Jian
CJ
D000596:Amino Acids / Q000737:chemistry*; D003124:Colorimetry / Q000379:methods; D006046:Gold; D036103:Nanotechnology; D013438:Sulfhydryl Compounds
D000596:Amino Acids; D013438:Sulfhydryl Compounds; D006046:Gold