Rational Design of Nanoparticles with Deep Tumor Penetration for Effective Treatment of Tumor Metastasis

The limited penetration of nanoparticles in primary tumors and metastases remains a great challenge for effective treatment of tumor metastasis. This review outlines the current approaches and summarizes the rational design of nanoparticles with deep tumor penetration capacity for anti-metastasis treatment. There are two ways to achieve better tumor penetration; through rational regulation of the physicochemical properties of nanoparticles and through remodeling of the tumor microenvironment, including the tumor vasculature and stromal environment. Moreover, biomimetic strategies that integrate the advantages of nanoparticles and metastasis-homing molecules during cancer cell metastasis are discussed. These efforts have led to promising results in facilitating intratumoral permeation of various nanoparticles to enhance antitumor effects. The considerations and some feasible future directions for deep tumor penetration strategies are proposed to improve tumor metastasis therapies.