Enzymatic synthesis of a DNA-templated alloy nanocluster and its application in a fluorescence immunoassay

Abstract

An enzymatic synthesis strategy of a DNA-template alloy nanocluster is presented. In this strategy, alkaline phosphatase (ALP) catalysed pyrophosphate (PPi) hydrolysis broke the coordination between Cu 2+ and PPi.The fluorescent DNA-template alloy nanoclusters were produced in situ through the reduction of the Cu 2+ and Ag + in the presence of single strand DNA (ss DNA). The fluorescence intensity of the alloy nanocluster was related to the concentration of ALP. This fluorescence turn-on strategy exhibited high sensitivity and selectivity for the ALP assay. Additionally, this strategy was also applied in an ALP-linked immuno-sorbent assay for a-fetoprotein (AFP) detection. Taking AFP as the model protein, it could be detected at a range from 10 ng mL À1 to 150 ng mL À1 and the detection limit was 4 ng mL À1 (0.042 nM). Finally, the diagnostic capability and practical application of this method was demonstrated by detecting AFP in human blood serum.

Inner Filter Effect-Based Sensor for Horseradish Peroxidase and Its Application to Fluorescence Immunoassay

“…The inset graph shows a quasi-linear relationship between I/I 0 and the logarithm of AFP concentration from 0.05−10 ng/mL, and then the fitted linear data could be expressed as I/I 0 = 0.646− 0.304 Log (C HRP ) (ng/mL), R 2 = 0.985, where 0.05 ng/mL AFP can be easily detected. This value is lower than those in previously reported fluorescence immunoassay for AFP, 29,44,45 and more significantly, has already satisfied the need for the clinical detection.…”

CsPbCl3 perovskite quantum dots/TiO2 inverse opal photonic crystals for efficient photoelectrochemical detection of alpha fetoprotein

“…PEC has attracted extensive interests in biological and environmental analysis fields with the advantage of high sensitivity as opposed to the above methods [16]. Additional benefits in comparison with fluorescence sensing [17][18][19], electrochemical sensing [20], and local surface plasma resonance (LSPR) method [21] are simple sensing technique, rapid response and low-cost, which becomes a significant issue in array-based analysis.…”