A sandwich-type surface stress biosensor based on self-assembled gold nanoparticles in PDMS film for BSA detection

Polydimethylsiloxane (PDMS) films compositing with gold nanomaterials are of growing interest in biosensor applications. However, low compatibility between gold and PDMS limits their sensitivity in biosensing. Herein, we reported a surface stress biosensor based on the gold nanoparticle-PDMS (AuNP-PDMS) film for detection of bovine serum albumin (BSA). The AuNPs-PDMS film was fabricated by in-situ reduction of PDMS and further reduction of glucose. The compatibility between gold and PDMS was improved by two-step reduction of AuNPs. The surface stress biosensor can specifically detect BSA molecules in the concentration range of 0 to 50 μg/mL with direct assay and sandwich assay, respectively. The sandwich assay amplified the surface stress and lowered the detection limit to 0.035 μg/mL, which is lower than that of direct assay. Moreover, the sandwich-type biosensor exhibits stability, repeatability and specificity. Our investigations will inspire the development of new method for biomolecules detection.