A self-assembled HSA–ICG nanoprobe enables accurate photoacoustic thermometry and feedback-controlled tumor photothermal therapy

Accurate thermometry is crucial for safe and effective tumor photothermal therapy. However, existing non-invasive methods are often limited by their penetration depth, temporal resolution, or accuracy. Here, we present a self-assembled HSA–ICG nanoprobe (HSA–ICG NP), formed by integrating FDA-approved indocyanine green (ICG) with human serum albumin (HSA), as a simple yet robust tool for precise photoacoustic (PA) thermometry and feedback-controlled photothermal therapy. HSA stabilizes ICG and enhances temperature sensitivity, enabling high-resolution thermal mapping on a custom-built PA platform. Validation in tissue-mimicking phantoms and ex vivo tissues demonstrated excellent quantitative accuracy, with mean temperature errors of 0.42 °C and 0.48 °C, respectively. In tumor-bearing mice, the nanoprobe provided real-time, spatially resolved temperature maps that visualized intratumoral heat propagation and supported controlled photothermal dosing. These results establish the HSA–ICG NP as a clinically relevant biomaterial that integrates imaging and therapy, providing a reliable approach for precise and translatable PA temperature guidance in tumor photothermal therapy.