Stimuli-responsive nanomaterials for eradicating intratumoral bacteria and augmenting tumor therapy efficiency:...

Tumor therapy remains one of the major challenges in medicine. Tumor-associated bacteria have recently emerged as crucial regulators of the tumor microenvironment, profoundly influencing the occurrence, development, immune response, and therapeutic efficacy of tumors, including intratumoral and intracellular bacteria. In particular, intratumoral and intracellular bacteria could be the effective targets to boost tumor therapy. However, several limitations remain for both antimicrobial therapy and tumor therapy in clinical, including drug resistance, low therapy efficiency, high recurrence rates, etc. Encouragingly, stimuli-responsive nanomaterials have significantly contributed to overcome these limitations. In this review, the different types of intratumoral and intracellular bacteria present in the tumor microenvironment were first introduced. Next, it summarizes the mechanisms by which these bacteria affect the biological activity of tumor cells. Then, the applications and mechanisms of various stimuli-responsive nanomaterials in antimicrobial therapy to enhance tumor therapy are discussed. Subsequently, advances in improving tumor therapy by intratumoral and intracellular antibacterial strategies are highlighted. Additionally, the future concerns and solutions of stimuli-responsive nanomaterials are examined. Finally, the current challenges associated with using antibacterial strategies for tumor therapy are revealed, along with prospective future development directions.