Ultrasound-activated macrophage-bomb for enhanced imaging and drug delivery in hepatocellular carcinoma

In the context of hepatocellular carcinoma (HCC) treatment, this study introduces a biomimetic "bomb" approach to target HCC by utilizing macrophages (MAs) as ultrasound-responsive carriers. This advanced biomimetic drug delivery system (MAs-DOX/PFP/Ms, MAs-DPM) encapsulates doxorubicin (DOX) and perfluoropentane (PFP) and is designed to precisely target HCC. MAs-DPM exhibits excellent drug loading capacity and biocompatibility, can effectively release DOX and enhance ultrasound imaging capabilities under ultrasound irradiation (UI). Experiments confirmed that MA maintained its biological activity and vitality during co-incubation and phagocytosis with DOX-loaded DPM, and microscopy confirmed that MA effectively engulfed DPM without changing cell morphology or function. Transwell experiments demonstrated that this bionic "bomb" (MAs-DPMs) not only retained the tumor targeting ability of macrophages, but also successfully delivered therapeutic drugs to tumor cells. Compared with samples without UI treatment, UI significantly increased the release of DOX from MAs-DPM, enhanced the drug release rate and inhibited the growth of HCC cells. Live/Dead staining experiments further intuitively revealed the precise "biobomb" effect of MAs-DPM under UI, effectively proving its ability to inhibit HCC cell proliferation. In vivo studies demonstrated that MAs-DPM was able to proficiently localize tumor sites within 24 h. Furthermore, the ultrasound-mediated phase transition of PFP enhanced the imaging efficacy, confirming the feasibility of macrophage-mimicking biological bombs for real-time in vivo ultrasound tracking. In the tumor-bearing nude mouse model, UI-treated MAs-DPMs remarkably delayed tumor growth and prolonged survival time compared with other groups. Subsequent histological and serum index evaluation further confirmed the in vivo safety of MAs-DPMs, and UI-treatment did not induce significant histological or pathological changes or statistical differences in vital organ or serum markers. These experiment results highlight the great potential of MAs-DPM as a strategic approach for the diagnosis and treatment of HCC.