A facile and robust SERS platform for highly sensitive and reproducible detection of uracil-DNA glycosylase using target-activated plasmonic coupling

Abstract

The self-assembly plasmonic nanoparticles with effective coupling have drawn considerable interest in quantitative surface-enhanced Raman scattering (SERS) detection, which facilitate their practical applications in chemical and biomolecular analysis. Herein, we report the development of a robust, sensitive and reproducible SERS platform for Uracil-DNA glycosylase (UDG) quantification using target-activated plasmonic coupling. This system consists of DNA substrates and Raman dyes-decorated gold nanoparticles (AuNPs) that functions as a target-recognition and SERS signal-output tool, and two kinds of enzymes, exonuclease I (Exo I) and endonuclease IV (Endo IV) that are utilized to degrade DNA substrates on AuNPs for controllable self-assembly of plasmonic nanoparticles. On account of this skilled design of SERS system, self-assembled hot spots with uniform interparticle gap and narrow enhancement factors (EFs) can be readily and repeatedly constructed by target-activated dual enzymatic cleavage reaction, which allows highly sensitive and reproducible SERS sensing of target UDG. Under optimized experimental conditions, the proposed biosensor exhibits excellent analytical performance toward the detection of UDG with a detection limit of 4.29 × 10−4 U mL−1 within a linear range of 1.0 × 10−3 U mL−1 to 10 U mL−1 for UDG, along with a favorable specificity and reproducibility. In addition, the practical applicability of this biosensor is demonstrated by the detection of UDG in cell extracts with satisfactory results. Hence, the target-activated plasmonic coupling-based strategy indeed creates a robust and convenient platform for UDG identification and related biomedicine research and clinical diagnosis.