Mussel-Inspired Tantalum Nanocomposite Hydrogels for In Situ Oral Cancer Treatment.

Oral squamous cell carcinoma (OSCC) is one of the most common oral malignancies. Radiotherapy is the primary noninvasive treatment of OSCC for avoiding surgery-induced facial deformities and impaired oral function. However, the specificity of in situ OSCC limits radiotherapeutic effects because of the hypoxia-induced low radiosensitivity of tumors and the low radiation tolerance of surrounding normal tissues. Here, we design a highly efficient and low-toxic radiosensitization strategy. On the one hand, biocompatible poly(vinyl pyrrolidone)-modified tantalum nanoparticles (Ta@PVP NPs) not only have strong X-ray deposition capability to upregulate oxidative stress but also have photothermal conversion efficiency to improve hypoxia for tumor radiosensitivity. On the other hand, to optimize the spatial distribution of Ta@PVP NPs within tumors, mussel-inspired catechol with bioadhesive properties is grafted on tumor microenvironment-responsive sodium alginate (DAA) to form in situ hydrogels for precision radiotherapy. On this basis, we find that Ta@PVP-DAA hydrogels effectively inhibit OSCC development in mice under photothermal-assisted radiotherapy without facial deformities and damage to surrounding normal tissues. Overall, our work not only promotes the exploration of Ta@PVP NPs as new radiosensitizers for OSCC but also develops a nanocomposite hydrogel system strategy as a promising paradigm for the precision treatment of orthotopic tumors.