Osteosarcoma is one of the major bone cancers, especially for youngsters. The current treatment usually requires systemic chemotherapy and the removal of bone tumors. Titanium (Ti)-based implants can be modified as local drug delivery (LDD) systems for controllable and localized chemotherapeutic drug release. In this work, a pH-responsive Ti-based LDD prototype was designed by introducing polydopamine (PDA) to release doxorubicin (DOX) around osteosarcoma cells with low pH. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and a contact angle meter were applied for surface characterization. Both direct and indirect cell culture modes were performed for biocompatibility and biofunction assessments. The results indicate that the Ti-based LDD prototype exhibits significant pH-dependent DOX release. The cumulative release can reach up to approximately 40% at pH = 6.0 after 72 h, but only around 20% at pH = 7.4. The Ti-based LDD implant shows good biocompatibility with approximately 93% viability of MC3T3 cells after direct culture in vitro for 24 h. Both direct and indirect culture modes verify the good anti-osteosarcoma function of the LDD implant, which should be attributed to the pH-responsive release of DOX.

Titanium (Ti)-based metallic biomaterials (MBs) are traditionally employed as mechanical supports and constraints in clinical practice, owing to their superb comprehensive mechanical properties, great corrosion resistance, and good biocompatibility. Recently, Ti-based MBs have emerged as promising candidates for antitumor applications. These developments focus on the functionalization of Ti-based MBs to inhibit tumor propagation and recurrence. This work systematically examines the antitumor approaches of Ti-based MBs and categorizes them into physical and chemical approaches. Physical strategies, such as the photothermal and photocatalytic techniques, are usually related to material-specific properties. Chemical approaches often employ controlled local drug delivery (LDD) systems. Ti-based LDD systems enable the targeted release of chemotherapeutics, metal ions, or immunomodulatory agents at tumor sites. This review highlights the efficacy of these surface-functionalized Ti-based MBs against diverse tumors. Additionally, the challenges and prospects of antitumor Ti-based MBs are also discussed.