Electrospun polyacrylonitrile film modified with Ag triangle nanoplates as flexible SERS substrates for HBD-2 detection.

A flexible silver triangular nanoplate (Ag TNPs)@m-phenylenediamine (mPD)@polyacrylonitrile (PAN) skin patch based on electrospinning is fabricated and applied to detect human beta-defensin 2 (HBD-2) by using surface-enhanced Raman scattering (SERS). First, PAN was used as the base material to create a fibrous membrane through electrospinning. The fibers were then modified with Ag TNPs by mPD endowing positive charges, forming a flexible Ag TNPs@mPD@PAN substrate. The flexible substrate features advantages of simple preparation, low cost, and convenient portability, which are suitable for in situ rapid detection on irregular surfaces. The combination of the flexible Ag TNPs@mPD@PAN substrate with Ag TNPs probes enabled the specific detection of HBD-2. It demonstrated satisfactory sensitivity and reproducibility with a wide detection range of 100-10 ng/mL and a limit of detection (LOD) of 59.57 fg/mL. Eventually, the flexible substrate was applied to HBD-2 detection on the surface of contaminated chicken skin. This study provides a simple and highly sensitive method for the detection of HBD-2, offering a novel approach for the non-invasive rapid diagnosis of psoriasis and the monitoring of disease progression.