Optical Physical Unclonable Functions Based on Nanostructured SiO₂/PDMS Composite Films for Biochip Anti-counterfeiting

Optical physical unclonable functions (PUFs) present an innovative solution for verifying the authenticity of clinical biochips. However, achieving biocompatibility and minimizing interference with biochip accuracy remain critical challenges. Here, we report optical PUFs based on nanostructured silica (SiO2)/polydimethylsiloxane (PDMS) composite films. Amorphous SiO2 nanoparticles, synthesized via the sol–gel method, are randomly dispersed within the PDMS matrix through ultrasonication and spin-coating processes. The interplay between the disordered PDMS structure and the nonuniform distribution of SiO2 nanoparticles enhances the complexity of the Raman signals generated by the optical PUFs while ensuring biocompatibility and minimal interference with biochip accuracy. Furthermore, the efficacy of these optical PUFs is assessed by examining key performance metrics, including randomness, uniqueness, reproducibility, and encoding capacity. Additionally, the conceptual application of these optical PUFs for securing biochip supply chains is showcased, providing a robust solution to enhance the security of these critical devices.