Nanomaterials with controllable release of nitric oxide and their biomedical applications

Nitric oxide（NO） is an endogenous gas messenger molecule that can regulate a variety of physiological functions. NO in low concentration can regulate smooth muscle, maintain iron homeostasis, and mediate neurotransmission. High concentrations of NO can provide a defense mechanism. Important physiological functions make NO a hot therapeutic gas molecule in the field of biomedicine. However, existing NO donors have limitations such as poor stability, uncontrolled release, and lack of targeting, which limit their further application. With the development of nanotechnology, researchers have synthesized a series of nanomaterials that can release NO in a controlled manner and applied them in the field of biomedicine. This review introduces the types of NO donors and the characteristics of common NO nanocarriers. Then, the applications of these NO-releasing nanomaterials in biomedical fields, such as treatment of cardiovascular diseases and tumor treatment, are summarized. Finally, the challenges and prospects in this field are discussed.