Recent progress in two-dimensional nanomaterials for cancer theranostics

• The synthesis and modification methods of different types of 2D nanomaterials are reviewed. • Recent advances in 2D nanomaterials for cancer treatment and imaging are systematically summarized. • 2D nanomaterial-based cancer theranostics are comprehensively reviewed. • The outlook and challenges of 2D nanomaterials in biomedical applications are discussed. Two-dimensional (2D) nanomaterials have drawn much attention by virtue of their unique physicochemical properties and numerous potential applications. Owing to their large specific surface areas, 2D nanomaterials can effectively load chemotherapeutic drugs for chemotherapy, or combine with other therapeutic agents such as photosensitizers for photodynamic therapy (PDT), immunomodulators for immunotherapy, and small interfering RNA for gene therapy. Notably, the majority of 2D nanomaterials themselves can be used as photothermal therapy (PTT) agents because of their unique optoelectronic properties. A variety of 2D nanomaterial-based combination therapies, such as PTT-chemotherapy, PTT-immunotherapy, and PTT-PDT-chemotherapy, can be designed to achieve higher antitumor efficacy than monotherapies. Additionally, 2D nanomaterials have proven to be an advanced tool to load imaging elements for cancer imaging or imaging-guided cancer treatments. Herein, we review top-down and bottom-up strategies for 2D nanomaterial synthesis and related methods for chemical and physical surface modifications. Recent progress in 2D nanomaterials for cancer treatments from the perspective of each type of 2D nanomaterials and imaging, as well as cancer theranostics, are comprehensively summarized.