Recent Progress in the Design of Hypoxia-Specific Nano Drug Delivery Systems for Cancer Therapy

Hypoxia is a salient feature in many solid tumors and an important player in tumor growth and progression. Increasing evidence suggests hypoxia plays major roles in the angiogenesis, metastasis, and resistance toward conventional cancer therapy treatments such as chemotherapy, radiotherapy, and photodynamic therapy. However, the exact reason that makes hypoxia a problem is also an opportunity for the development of new therapeutic modalities. The low oxygen level and highly reductive environment provide great options for stimuli-sensitive drug release in a highly target-specific manner. The use of nanoparticle-based systems for hypoxia-selective drug delivery is a relatively new but rapidly progressing research area. This report summarizes the recent trends and advances in the development of new hypoxia-specific nanomedicines. The background, the current progress, and what could be done in the future to achieve greater success in cancer therapy are discussed.