A tumor targeted antifouling upconversion nanoplatform for fluorescence imaging and precise photodynamic therapy triggered by NIR laser.

Photodynamic therapy (PDT) has been considered as a promising treatment in the biomedical field because of low toxicity to normal tissues and minor trauma area. However, the PDT effect of materials is greatly affected by many factors, such as nonspecific adsorption and poor light penetration, etc. In this work, an intelligent nano platform has been constructed based on upconversion nanoparticles (UCNPs) loaded with a large amount of photosensitizers Ce6, which could specifically light up tumor tissues and stimulate the production of reactive oxygen species (ROS) under 980 nm near-infrared (NIR) irradiation, exhibiting a conspicuous imaging and therapeutic effect of PDT treatment for deep tumors. An excellent anti-fouling performance in complex biological substrate was obtained upon the judicious introduction of anti-fouling peptide, which also contributed to the improved PDT efficiency. In addition, the specificity of nanoplatform to malignant breast cancer cells was realized by modification of polypeptide targeting for HER2. This anti-fouling nanoplatform provided an original paradigm for the development of fluorescence imaging and PDT for deep tumor tissue with high targeting and therapeutic efficacy, promising to be used in the early therapy of malignant breast cancer specifically.