Nanobody‐Conjugated Theranostic Prodrug Targeting α v β 3 Integrin Enables Precision Cancer Therapy With Real‐Time Imaging

ABSTRACT Theranostic prodrugs that integrate diagnostic and therapeutic functionalities represent a promising avenue for precision oncology. In this study, we report the rational design, synthesis, and preclinical evaluation of a nanobody‐based α v β 3 integrin‐targeted theranostic prodrug ( NBD ). The system incorporates a glutathione‐responsive disulfide linker to enable selective release of doxorubicin within the tumor microenvironment, alongside an aza‐BODIPY near‐infrared fluorophore that providesactivatable imaging capability. Compared to its cRGD peptide‐conjugated counterpart ( cRBD ), NBD demonstrated superior tumor selectivity, intracellular activation, and cytotoxic potency in α v β 3 ‐overexpressing cancer cell lines. In vivo studies using SKOV3 xenograft models confirmed prolonged tumor retention, enhanced drug accumulation, and potent tumor suppression, with minimal systemic toxicity. Moreover, real‐time imaging enabled precise monitoring of prodrug activation and distribution. These findings highlight the unique advantages of nanobody‐guided theranostic platforms in enabling targeted drug delivery, reducing off‐target effects, and facilitating image‐guided therapy. The modular design of NBD provides a versatile framework for advancing personalized cancer treatment strategies.