SERS monitoring of biothiols in serum based on thiol-alkyne click reaction

A novel surface-enhanced Raman scattering (SERS) sensing strategy based on thiol-yne click reactions for highly sensitive and selective detection of biothiols in serum has been developed. By combining gold-core silver-shell nanoparticles (Ag@AuNPs) with 1,4-diethynylbenzene (DTBN) and immobilizing them in an agarose hydrogel matrix, a flexible SERS sensor was constructed. The alkyne group (C ≡ C) of DTBN generated a strong characteristic signal in the Raman-silent region (2209 cm⁻1). This group underwent a click reaction with the thiol (-SH) group of biothiols under a photoinitiator, leading to a proportional attenuation of the SERS signal intensity with increasing thiol concentration. Experimental results demonstrated a linear detection range for Cys from 1 × 10⁻5 to 1 × 10⁻10 M, with a detection limit as low as 16 pM, surpassing traditional methods. Additionally, the three-dimensional network structure of the hydrogel matrix effectively shielded interference from serum components, and recoveries of 93.4%–113.3% confirmed its applicability in complex biological samples. The prepared Ag@AuNPs@DTBN hydrogel chip exhibited excellent stability and reproducibility, providing a new approach for rapid clinical monitoring of biothiols. This advancement holds promise for early warning and therapeutic evaluation of cardiovascular and neurodegenerative diseases.