Fig. 8.

Illustration of multiple strategies for improving tumor penetration of nanomedicine. (A) Utilization of external stimuli, such as NIR light, ultrasound, magnetic fields and other physical sources to induce in vivo response of nanomedicine, leading to its size shrinkage to improve its antitumor therapeutic effect. (B) Utilization of internal stimuli to strengthen the antitumor effect of nanomedicine by improving drug penetration through the action of enzymes like MMPs and HAase or at a low pH in the tumor microenvironment. (Fig. 8A and B were created with BioRender.com.).