Nanotechnology enabled reactive species regulation in biosystems for boosting cancer immunotherapy

Reactive species are common in biosystems, playing vital roles in a wide spectrum of cell signaling. Taking advantage of the intriguing properties of nanomaterials, nanotechnology has been applied as a promising tool for regulating reactive species in the development of nanomedicines for cancer therapy, a research topic that has been extensively reviewed. However, in the context of cancer immunotherapy, the interplay between reactive species, tumors and immune system is rather complex: Reactive species not only play as cytotoxic chemicals for tumor cells, but also regulate tumor microenvironment and act as signaling messengers for immune cells. Precise control over the dose and location of reactive species via nanotechnology is the key to determine the immunotherapeutic outcome. A review article on this topic is rare to our knowledge. Herein, recent progress in nanotechnology enabled reactive species regulation strategies in various biosystems, including cancer cells, antigen presenting cells and tumor microenvironment for boosting cancer immunotherapy, is summarized. The design principles based on the mechanism of action of reactive species in different bio-targets are particularly highlighted. Perspectives on the remaining challenges in this emerging research field and possible future directions are also provided. (C) 2020 Elsevier Ltd. All rights reserved.