The progress and perspective of strategies to improve tumor penetration of nanomedicines

Tumor penetration is important for effectively tumor targeting drug delivery. Recently, many researches are published to overcome the barriers that restrict tumor penetration and improve drug delivery efficiency. In the mini review, we first analyzed the barriers influence the tumor penetration, including tumor microenvironment barriers, nanoparticle properties, and interaction barriers between tumor and nanoparticles. To overcome the barrier, several strategies are developed, including modulating tumor microenvironment, changing particle size, transcytosis enabled tumor penetration, cell penetrating peptide modification and overcoming binding site barrier, which could effectively improve tumor penetration, and finally enhance tumor treatment outcome.