Modulation of Near‐Infrared Afterglow Luminescence in Inorganic Nanomaterials for Biological Applications

Abstract

Abstract Near‐infrared afterglow luminescent inorganic nanomaterials (NIR‐ALINs) possess the unique property of continuing to emit near‐infrared (NIR) luminescence after excitation ceases. They demonstrate excellent photostability, deep tissue penetration, and high imaging signal‐to‐noise ratio (SNR). Additionally, NIR‐ALINs can be re‐excited in vivo using visible (Vis), NIR light or X‐rays, which avoids the need for continuous in situ excitation, thus eliminating autofluorescence of biological tissues and reducing the tediousness of multiple injections. These features make NIR‐ALINs particularly attractive for biological applications. In recent years, a series of NIR‐ALINs with prolonged afterglow time and enhanced luminescence intensity have been discovered. However, the development of NIR‐ALINs still faces significant challenges, as their NIR afterglow performance is usually insufficient to satisfy practical biological applications. There is still a lack of systematic analysis of the strategies for the regulation of NIR afterglow luminescence in inorganic nanomaterials. This review highlights the rational design and modulation strategies of NIR‐ALINs, focusing on host substrate selection, trap engineering modulation and surface modification. Moreover, the biological applications of NIR‐ALINs in bioimaging, bio‐detection and disease therapy are summarized. Finally, the present challenges and perspectives in biological applications, such as insufficient afterglow properties and unclear biosafety, are also discussed.