Tumor microenvironment-responsive size-switchable drug delivery nanosystems

Compared with ordinary chemotherapeutic drugs, the variable-size nanoparticles (NPs) have better therapeutic effects and fewer side effects.This review mainly summarizes the strategies used to construct smart, size-tunable nanocarriers based on characteristic factors of tumor microenvironment (TME) to dramatically increase the penetration and retention of drugs within tumors.Nanosystems with changeable sizes based on the TME have been extensively studied in the past decade, and their permeability and retention have been greatly improved, making them a very promising treatment for tumors.