MilliporeSigma
  • Home
  • Search Results
  • Urchin-like (gold core)@(platinum shell) nanohybrids: A highly efficient peroxidase-mimetic system for in situ amplified colorimetric immunoassay.

Urchin-like (gold core)@(platinum shell) nanohybrids: A highly efficient peroxidase-mimetic system for in situ amplified colorimetric immunoassay.

Biosensors & bioelectronics (2015-03-31)
Zhuangqiang Gao, Mingdi Xu, Minghua Lu, Guonan Chen, Dianping Tang
ABSTRACT

The development of signal-amplified colorimetric immunoassay relies on the design of highly efficient signal-transduction tags. One promising route is to exploit a novel enzyme mimetic system as the signal label. Herein, we report that urchin-like (gold core)@(platinum shell) nanohybrids (Au@PtNHs) can be utilized as a highly efficient peroxidase mimetic system for in situ amplified colorimetric immunoassay of prostate-specific antigen (PSA, one kind of tumor marker). Initially, urchin-like Au@PtNHs were discovered to outperform horseradish peroxidase (HRP) by a vast margin in terms of the turnover number toward hydrogen peroxide (H2O2)-3,3',5,5'-tetramethylbenzidine (TMB) system and the stability against high temperatures and HRP inhibitors. Based on this discovery, the assay was simply carried out on a capture antibody-immobilized microplate by using the Au@PtNH-labeled detection antibody as a signal-transduction tag with a sandwich-type assay mode. The colorimetric signal stemmed from the labeled Au@PtNHs toward catalytic oxidation of TMB-H2O2 system. Experimental results indicated that the Au@PtNH-based colorimetric immunoassay could display a good colorimetric response toward PSA in the dynamic working range of 5-500 pg mL(-1) with a low detection limit of 2.9 pg mL(-1). Meanwhile, the developed immunoassay exhibited good precision and reproducibility, high specificity and acceptable accuracy for the detection of clinical serum samples. These results open up a new horizon for the development of highly sensitive, highly stable and inexpensive non-enzyme immunoassay platforms as an alternative to conventional enzyme-based immunoassay platforms.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
L-Ascorbic acid, ACS reagent, ≥99%
Sigma-Aldrich
Citrate Concentrated Solution, BioUltra, for molecular biology, 1 M in H2O
Sigma-Aldrich
L-Ascorbic acid, puriss. p.a., ≥99.0% (RT)
Sigma-Aldrich
3,3′,5,5′-Tetramethylbenzidine, ≥98.0% (NT)
Sigma-Aldrich
L-Ascorbic acid, puriss. p.a., ACS reagent, reag. ISO, Ph. Eur., 99.7-100.5% (oxidimetric)
Sigma-Aldrich
3,3′,5,5′-Tetramethylbenzidine, ≥99%
Sigma-Aldrich
L-Ascorbic acid, 99%
Sigma-Aldrich
L-Ascorbic acid, BioUltra, ≥99.5% (RT)
Sigma-Aldrich
3,3′,5,5′-Tetramethylbenzidine, ≥98% (TLC)
Sigma-Aldrich
L-Ascorbic acid, powder, suitable for cell culture, γ-irradiated
Sigma-Aldrich
L-Ascorbic acid, meets USP testing specifications
Sigma-Aldrich
3,3′,5,5′-Tetramethylbenzidine, tablet, 1 mg substrate per tablet
Sigma-Aldrich
L-Ascorbic acid, reagent grade, crystalline
Sigma-Aldrich
L-Ascorbic acid, reagent grade
Sigma-Aldrich
L-Ascorbic acid, BioXtra, ≥99.0%, crystalline
Sigma-Aldrich
L-Ascorbic acid, suitable for cell culture, suitable for plant cell culture, ≥98%
Sigma-Aldrich
L-Ascorbic acid, suitable for plant cell culture
Sigma-Aldrich
Citrate Concentrated Solution, BioReagent, suitable for coagulation assays, 4 % (w/v)
Sigma-Aldrich
L-Ascorbic acid, FCC, FG