Smart Inorganic Nanomaterials for Tumor Microenvironment Modulation

The tumor microenvironment (TME) is characterized by hypoxia; acidic pH; oxidative stress; and immune suppression; all of which severely impair the efficacy of conventional cancer therapies. Recent advances in inorganic nanotechnology have led to the development of smart nanomaterials capable of modulating these abnormal features; thereby reprogramming the TME toward a more therapy-responsive state. Inorganic nanomaterials such as manganese dioxide; iron oxide; and cerium oxide can selectively alleviate hypoxia; buffer acidity; regulate redox balance; and even stimulate anti-tumor immunity through catalytic or structural mechanisms. These materials can further serve as carriers for stimuli-responsive drug delivery; enabling synergistic therapies that include chemodynamic; photothermal; and immunomodulatory treatments. This review summarizes recent developments in smart inorganic nanomaterials for TME modulation; discusses design considerations including biosafety and biodegradability; and evaluates the current translational status and future directions.