A tumor-microenvironment-activated nanoplatform of modified SnFe2O4 nanozyme in scaffold for enhanced PTT/PDT tumor therapy

Abstract

Phototherapy has attracted widespread attention for cancer treatment due to its noninvasiveness and high selectivity. However, severe hypoxia, overexpressed glutathione and high levels of hydrogen peroxide (H2O2) of tumor microenvironment limit the antitumor efficiency of phototherapy. Herein, inspired by the specific response of nanozymes to the tumor microenvironment, a simple and versatile nanozyme-mediated synergistic dual phototherapy nanoplatform is constructed. In this study, tin ferrite (SnFe2O4, SFO) nanozyme as a photosensitizer was surface modified with polydopamine (denoted as P-SFO) and incorporated into poly(l-lactide) to fabricate an antitumor scaffold fabricated by selective laser sintering. On one hand, SFO nanozyme could act as a photoabsorber to convert light energy into heat for photothermal therapy (PTT). On the other hand, it played a role of photosensitizer in transferring the photon energy to generate reactive oxygen species (ROS) for photodynamic therapy (PDT). Importantly, its multivalent metal ions redox couples would decompose H2O2 into O2 for enhancing O2-dependent PDT and consume glutathione to relieve antioxidant capability of the tumors. Besides, polydopamine as a photothermal conversion agent further enhanced the photothermal performance of SFO. The results revealed the PLLA/P-SFO scaffold possessed a photothermal conversion efficiency of 43.52% for PTT and a high ROS generation capacity of highly toxic ·O2− and ·OH for PDT. Consequently, the scaffold displayed a prominent phototherapeutic effect with antitumor rate of 96.3%. In addition, the PLLA/P-SFO scaffolds possessed good biocompatibility for cell growth. These advantages endow PLLA/P-SFO scaffold with extensive applications in biomedical fields and opened up new avenue towards nanozyme-mediated synergistic phototherapy.