Integrating green chemistry with biomedical innovation: the role of biocompatible ionic liquids and ionic liquid nanoparticles in therapeutic applications.

Biocompatible ionic liquids (ILs) have emerged as a new class of versatile materials that sit at the intersection of sustainability and biomedical innovation. Unlike traditional volatile organic solvents, ILs are salts that remain liquid at or near room temperature, offering distinctive features such as negligible vapor pressure, high thermal and chemical stability, broad solvation ability, and remarkable structural tunability. These properties have made them attractive as green solvents and catalysts, reducing environmental impact while improving reaction efficiency. More recently, attention has expanded from their conventional chemical roles to their potential as biologically active agents and functional materials. In particular, ionic liquid-based nanoparticles (ILNs) have opened new opportunities in medicine and biotechnology by combining the adaptable chemistry of ILs with the nanoscale advantages of controlled size, high surface area, and enhanced stability. ILNs have been shown to improve drug solubility and targeted delivery, enhance enzyme stabilization, and exhibit antimicrobial and anticancer activities. Moreover, task-specific and bio-ionic liquids (TSILs and B-ILs) can be precisely engineered to balance biocompatibility with functionality, positioning them as promising candidates for applications in tissue engineering, biosensing, and sustainable therapeutics. Despite these advances, issues related to cytotoxicity, biodegradability, and scalability remain challenges to be addressed. This review explores the properties of biocompatible ILs, their role in nanoparticle synthesis, and their expanding applications across green chemistry and therapeutic sciences, highlighting their potential to serve as a bridge between environmental responsibility and human health.