Peptide-capped gold nanoparticle for colorimetric immunoassay of conjugated abscisic acid.
The pentapeptide Cys-Ala-Leu-Asn-Asn (CALNN) has been proved to be a powerful tool to stabilize the AuNPs. These CALNN-capped AuNPs have been used to develop various bioanalysis platforms. In this paper, the CALNN-capped AuNPs are proved to be a robust tool for aggregation-based colorimetric immunoassays as well. A colorimetric immunoassay strategy based upon the antibody-induced assembly of functionalized AuNPs for Abscisic Acid glucose ester (ABA-GE) determination has been developed. The ABA-functionalized AuNPs aggregate in the presence of specific antibody, accompanied by a color change of the solution. The color change is competitively inhibited by ABA-GE. The interparticle distance in aggregates is small due to the thin peptide layer on the AuNPs surface, and it is determined by the "Y" shape antibody linker as well. As a result of that, an obvious color change in the immunoassays is observed. Under the optimized conditions, a linear response range from 5 nM to 10 μM for ABA-GE determination is obtained, and the limit of detection (LOD) is evaluated to be 2.2 nM. This method is simple, homogeneous, and has potential for visual detection of ABA-GE.
Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China.
Guohua
G
Zhou
Yizhen
Y
Liu
Ming
M
Luo
Qinfeng
Q
Xu
Xinghu
X
Ji
Zhike
Z
He
D000040:Abscisic Acid / Q000032:analysis*; D000595:Amino Acid Sequence; D000906:Antibodies / Q000276:immunology; D003124:Colorimetry; D004952:Esters; D005947:Glucose / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D007118:Immunoassay; D053768:Metal Nanoparticles / Q000737:chemistry*; D009842:Oligopeptides / Q000737:chemistry* / Q000378:metabolism
D000906:Antibodies; D004952:Esters; D009842:Oligopeptides; D000040:Abscisic Acid; D006046:Gold; D005947:Glucose