Tumor microenvironment-mediated NIR-I-to-NIR-II transformation of Au self-assembly for theranostics

The misdiagnosis of tumors due to insufficient penetration depth or signal interference and damage to normal tissues due to indiscriminate treatment are the biggest challenges in using photothermal agents for clinical translation. To overcome these limitations, a strategy of switching from the near-infrared (NIR)-I region to the NIR-II region was developed based on tumor microenvironment (TME)-mediated gold (Au) self-assembly. Using zeolitic imidazolate framework-8 (ZIF-8) metal-organic framework-coated gold nanorods (AuNRs@ZIF-8) as a model photothermal agent, we demonstrated that only a NIR-I pho-toacoustic imaging signal was observed in normal tissue because ZIF-8 could prevent the aggregation of AuNRs. However, when ZIF-8 dissociated in the TME, the AuNRs aggregated to activate NIR-II photoacoustic imaging and attenuate the NIR-I signal, thereby allowing an accurate diagnosis of tumors based on signal transformation. Notably, TME-activated NIR-II photothermal therapy could also inhibit tumor growth. Therefore, this TME-activated NIR-I-to-NIR-II switching strategy could improve the accuracy of deep-tumor diagnoses and avoid the injury caused by undifferentiated treatment. Statement of significance Photothermal agents used for photoacoustic imaging and photothermal therapy have garnered great attention for tumor theranostics. However, always turned on near-infrared (NIR)-I laser (70 0-10 0 0 nm)-responsive photothermal agents face issues of penetration depth and damage to normal tissues. In contrast, tumor microenvironment-activated NIR-II smart photothermal agents exhibit deeper penetration depth and tumor selectivity. Therefore, a NIR-I-to-NIR-II switching strategy was developed based on tumor microenvironment-mediated Au self-assembly. This work provides a new strategy for developing tumor microenvironment-activated NIR-II smart photothermal agents.& COPY; 2023 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Automated summary

The misdiagnosis of tumors and damage to normal tissues are the main challenges in using photothermal agents for clinical translation. To overcome these limitations, a strategy of switching to the NIR-II region based on tumor microenvironment (TME)-mediated gold self-assembly was developed. The use of TME-activated NIR-II photothermal agents allows for accurate tumor diagnosis and inhibition of tumor growth.