Mixed-charge bionanointerfaces: Opposite charges work in harmony to meet the challenges in biomedical applications.

Understanding and regulation of the interfaces formed between materials and biological systems has been considered as one of the major tasks in nanotechnology, as the bionanointerfaces often exert profound effects on the fates and therapeutic outcomes of nanomaterials. In the last decades, materials with mixed-charge surfaces have witnessed fast development. The oppositely charged units on the materials' surface could work in a charge balanced way or a charge biased way, which offers much more possibilities to the bionanointerfaces than materials with singly charged surface. It has been found out that mixed-charge residues could bring about functionalities such as antifouling ability, pH-sensitivity, self-assemble propensity, thermal sensitivity, and so on. In this review, recent advances in developing mixed-charge bionanointerfaces would be carefully overviewed and the potential applications and challenges of mixed-charge materials in biomedical field will be discussed. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies Biology-Inspired Nanomaterials > Protein and Virus-Based Structures.