A Functional Air-Bubble Microlaser for Screening Photothermal Agents in Tumor Multicellular Model

Photothermal therapy employs photothermal agents (PTAs) to convert light energy into heat, enabling efficient treatment of various tumors and other diseases. However, it remains challenging to screen PTAs within complex multicellular environments sensitively and efficiently. Here, we introduce a functional air-bubble microlaser for PTA screening, enabling real-time, in situ, all-optical evaluation of heat generation by PTAs in a tumor multicellular environment. Thermally driven expansion and contraction of the bubble cavity produce a lasing-wavelength shift with an ultrahigh sensitivity of 2.085 nm °C^-1, allowing heat-based discrimination among PTAs. Constructed from biocompatible polymers, the air-bubble microlasers can be integrated into tumor multicellular models. The platform benchmarks PTAs across composition, size, dose, and combinatorial formulations and further evaluates targeting-specific PTAs by comparing localized heating in receptor-positive versus control models. This approach provides a precise, scalable assay for PTA evaluation and supports the development of preclinical translatable photothermal therapies.