Coomassie brilliant blue R-250 as a new surface-enhanced Raman scattering probe for prion protein through a dual-aptamer mechanism

•Coomassie brilliant dye was employed as Raman reporter and utilized to label the target protein.•Dual-aptamer was addressed, leading to high specificity towards PrP.•Silica shell of the nanoparticles served as versatile substrate for apamter immobilization.•The ensemble of Ag@Si NPs was utilized as the SERS substrate.

Surface-enhanced Raman scattering (SERS) spectra, which can provide large information about trace amount of chemical and biological species have been widely performed as a well-established tool in complex biological system. In this work, coomassie brilliant blue (R-250) with high affinity to proteins and high Raman activity was employed as a Raman reporter to probe prion protein (PrP) through a dual-aptamer mechanism, and thus an original strategy for PrP determination was proposed, which showed great potential to turn on the SERS response through specific recognition of anti-prion aptamers towards the target protein. Aptamers (Apt1 and Apt 2) recognizing distinct epitopes of PrP with high affinity were first conjugated to Ag@Si NPs, and Ag@Si-PrP/R-250-Ag@Si conjugates were obtained in the presence of PrP/R-250, inducing dramatically enhanced Raman signal. SERS responses enhanced with increasing amount of PrP and a linear equation of ISERS=6729.7+3091.2 cPrP was obtained in the range of 3.0–12.0×10−9 M with the determination coefficient of 0.988. The proposed strategy is simple, rapid, and high specificity to probe protein–aptamer recognition in the solution.

Graphical abstractCoomassie Brilliant Blue R-250 was successfully applied as a new Surface-enhanced Raman scattering reporter for protein labeling through a dual-aptamer mechanism, and an original strategy for PrP determination was proposed, which is simple, rapid, and high specific.Figure optionsDownload full-size imageDownload as PowerPoint slide