In vivo and in situ monitoring of doxorubicin pharmacokinetics with an implantable bioresorbable optical sensor.

Cancer treatment, particularly chemotherapy, requires balancing efficacy and toxicity. Although traditional moni toring methods can lead to suboptimal outcomes, emerging implantable chemical sensors can complement them by providing precise, real- time drug monitoring at tumor sites, although the technology remains in its early stages. Here, we introduce an ultrathin, bioresorbable implantable biosensor for real- time doxorubicin monitoring in vivo with high spatiotemporal resolution. The sensor amplifies the drug’s fluorescence, enabling successful tracking of doxorubicin through the skin in live mice following intravenous injection. When paired with a reusable electronic patch, the biosensor facilitates seamless data collection and wireless transmission. A 3- month biocompatibility study, including systemic toxicity assessments, histological and blood analyses, confirms complete biodegrada tion with no observed toxicity. By directly measuring chemotherapeutic drug levels in tissues over time, our sen sor enhances traditional monitoring methods, enabling clinicians to optimize dosing during cancer treatment and reduce the risk of locoregional recurrence following tumor removal.