EXO-DOX-VHH

While exosome-encapsulated doxorubicin provides effective drug delivery in cancer treatment, its application is significantly limited by a lack of selectivity that can cause unwanted side effects, hence, it remains a priority for ongoing improvement. So, we have investigated the improvement of cancer targeting by anti-HER2 VHH functionalized exosome (EXO) surface modification to deliver doxorubicin (DOX), both in vitro and in vivo, using a BALB/c mouse model of HER2-positive breast cancer. The surface of exosomes derived from BMMSCs was functionalized to conjugate anti-HER2 VHH by a peptide bond formation technique with a 60.2 % conjugation efficiency. Doxorubicin was loaded into anti-HER2 VHH-conjugated exosomes by the sonication method with an encapsulation efficiency of 35 %. The fabricated nanoformulation (EXO-DOX-VHH) was characterized by DLS, SEM, and WB; the result showed the size of EXO, EXO-DOX, and EXO-DOX-VHH to be 126.7, 144.2, and 161.3 nm, respectively. SEM confirmed that the (EXO-DOX-VHH) maintained a round shape, similar to the original exosome. Western blot analysis confirmed the presence of exosomal membrane proteins and the absence of the endoplasmic reticulum marker. The cellular uptake and MTT revealed binding selectivity of VHH 94.6 % and cytotoxicity of 74 % of (EXO-DOX-VHH) in HER2+ breast cancer cells. The in vivo experiment was conducted on four groups (5 per group) of BALB/C mice with a breast cancer model, using 18F-FDG Micro PET imaging before and after treatment. The results of 18F-FDG Micro PET imaging revealed a marked reduction in glucose metabolism in tumor-bearing mice treated with (Exo-Dox-VHH), showing significant differences in both maximum standardized uptake value (SUV max) and Tumor/muscle SUVmax ratio (TMR). Our findings suggest that anti-HER2 VHH can enhance targeted therapy and improve molecular imaging. Additionally, the preclinical results contribute to a better understanding of the tumor environment and may advance clinical theranostic applications.