A bone-targeting permeable nanomicelle acting as an icebreaker for enhancing chemotherapy of osteosarcoma

Osteosarcoma is one of the commonest malignant bone tumors in children and adolescents, and its preferred treatment is chemotherapy. However, the lack of sufficient blood vessels in the bone tissue and the dense collagen fibers in osteosarcoma severely weaken the drug-directional accumulation effect and intra-tumoral penetration, leading to poor therapeutic efficacy. Herein, we reported a bone-targeted permeable nanomicelle (Co1-PTX@DSAA) composed of aspartic acid (Asp)-modified dextran (DSAA) to deliver paclitaxel (PTX) and collagenase 1 (Co1) simultaneously for highly effective osteosarcoma treatment. The prepared nanomicelle possessed excellent osteosarcoma targeting ability as Asp can combine with hydroxyapatite (HAP) in bone. More intelligently, the surface-absorbed Co1 endowed PTX@DSAA with a special function like a nano-icebreaker, which could quickly destroy the collagen fibers to promote PTX penetration deeply in the tumor. Our work suggests that Co1-PTX@DSAA nanomicelles could quickly combine with HAP and Ca2+ at an adsorption rate of ∼ 60 % and ∼ 32 %, respectively. Meanwhile, the penetration depth of Co1-PTX@DSAA could even reach 70 μm in the multicellular spheroids (MCSs) model. The tumor treatment efficiency of Co1-PTX@DSAA is 1.51 times that of free PTX. Overall, this unprecedented nanomicelle can simultaneously facilitate drug accumulation and deep penetration in the tumor, which will provide a promising strategy for future safe and high-efficiency clinical osteosarcoma treatment.