Photonic fingerprint barcodes mediated by microsphere WGM lasing.

Optical encoding technologies have emerged as promising tools for biomedical sensing and single-cell tracking, offering unparalleled opportunities for high-precision biological analysis. However, conventional optical barcoding systems suffer from limited coding capacity, poor biocompatibility, and low signal-to-noise ratios. Here, we report a photonic fingerprint barcode platform mediated by biocompatible microsphere lasers, which leverages whispering gallery mode (WGM) lasing to generate unique, fingerprint-like optical signatures. By engineering the structural parameters and excitation conditions of biocompatible polymer microspheres, we generate six distinct photonic fingerprint barcodes, mirroring the arch, tented arch, left loop, right loop, double loop, and whorl patterns of human fingerprints. Each generated barcode is characterized by a unique barcode-like intensity spectrum and waveform profile, enabling high-throughput, label-free biological identification with exceptional specificity. This work establishes a versatile, biocompatible optical encoding strategy, offering a promising tool for precision medicine, single-cell tracking, and multiplexed biosensing.