Intelligent Size-Changeable Nanoparticles for Enhanced Tumor Accumulation and Deep Penetration.

Nanoparticles have shown great potential in tumor drug delivery. However, the accumulation and deep penetration behaviors of nanoparticles still need to be improved because of the barrier of tumor microenvironment. Recent days, intelligent aggregatable or shrinkable nanoparticles exhibit both good accumulation and deep penetration, providing the prospect for improved antitumor efficacy. This Spotlight first gives a concise introduction of the "size dilemma" in tumor accumulation and deep penetration and then goes in detail on our own contribution to the field of size aggregation and size shrinkage strategies. Also, we introduce the combination therapy of the size change strategy and other treatments, and the synergistic effect significantly improves the antitumor efficacy. In the end, we discuss the future directions for the potential applications.