Engineering design of cobalt-based biomaterials for advanced cancer theranostics: Multimodal synergy, scalable fabrication, and clinical translation

Despite established modalities such as chemotherapy and radiotherapy, cancer treatment remains hindered by off-target toxicity, drug resistance, and adverse effects. Cobalt-Based Biomaterials (Co-BMs) have emerged as versatile nanoplatforms for tumor theranostics, leveraging reversible Co 2+ /Co 3+ transitions to enable high-efficiency photothermal/photodynamic therapy, nanozyme catalysis, and reactive oxygen species (ROS) generation, supporting tumor microenvironment (TME) modulation and multimodal therapy. This review proposes a “structure-mechanism-translation” framework, systematically linking the physicochemical properties of Co-BMs with clinical needs, surpassing earlier reviews focused solely on synthesis or isolated applications. We describe the biological functions of Co-BMs ( e.g. , intracellular redox reactions, vitamin B12 synthesis, immune regulation, and cell proliferation and apoptosis), then overview current synthesis strategies for Co-BMs with diverse physicochemical characteristics ( e.g. , shape, surface modification, size), including template, etching, precipitation, sol-gel, hydro/solvothermal, and chemical vapor deposition methods. Furthermore, we highlight recent advances in multimodal tumor theranostics and microenvironment-responsive design, and critically examine key challenges. Finally, we discuss how current research informs future design principles to guide the development of next-generation multifunctional Co-BMs and advance their clinical translation in oncology.