Bioionic Liquids: Enabling a Paradigm Shift Toward Advanced and Smart Biomedical Applications

Ionic liquids (ILs) exhibit unique properties of good ionic conductivity, electrochemical and thermal stability, and nonflammability, which make them promising candidates for biomedical applications. The limitations of their cytocompatibility are enhanced by using bioionic liquids (BILs) derived from biological molecules such as amines, sugars, and organic acids. BILs can be synthesized using tailorable chemistries that enable their immobilization onto biopolymers. For example, the cholinium ion and its derivatives have found significant interest in tissue engineering and drug delivery systems. Ion‐doped BIL‐functionalized polymers and their composites can also be used to design pH and electrical responsive actuators and sensors. The cytocompatibility and low immunogenicity of BIL‐functionalized polymers enable the possibilities of their use for power storage devices as well as implantable devices. These devices are gaining recognition and importance in nucleic acid delivery and molecular medicine. This review focuses on the recent advances of BILs in biomedical applications. Specifically, the review explores BILs as agents for biopolymer functionalization and highlights BILs as solvents for supermolecular ionic networks.