Flexible and Biocompatible Physical Unclonable Function Anti-Counterfeiting Label

Optical physical unclonable functions (PUFs) have been proven to be one of the most effective anti-counterfeiting strategies. However, optical PUFs endowed with flexibility and biocompatibility have not been developed, limiting their application scenarios. Herein, biocompatible and flexible optical PUF labels are developed by randomly embedding microdiamonds in silk fibroin films. The PUF labels can be conformally attached onto the surface of complex shaped objects, providing the desired protection against fake and interior products. In this system, silk fibroin films serve as a flexible and biocompatible substrate, while the Raman signal of the microdiamonds serves as response of the excitation. The extremely high stability and random distribution of the microdiamonds ensure the performance of PUFs, and the maximum encoding capability of 2(10000) is finally realized. The cytotoxicity analysis results also verify the biosafety of the PUF system. In addition, the as-prepared PUF labels are attached onto the surface of polyethylene material, and human skin, and even have been implanted under chicken skin tissue, promising their practical applications.

Automated summary

Biocompatible and flexible optical PUF labels have been developed by embedding microdiamonds in silk fibroin films, providing protection against counterfeit products and complex shaped objects. The silk fibroin films serve as a flexible and biocompatible substrate, while the Raman signal of the microdiamonds acts as the response mechanism, ensuring high stability and random distribution of PUFs with a maximum encoding capability of 2(10000). The cytotoxicity analysis results confirm the biosafety of the PUF system, and the labels have shown promising practical applications on various surfaces including polyethylene material, human skin, and even implanted under chicken skin tissue.