Sensing vs Extraction: Functionalized Ionic Liquid as a Single Platform for Dual Applications with Biological Implications

A single platform for dual applications of metal-ion sensing and extraction with recyclability is a desirable system for sustainable environmental remediation. However, considering these two function’s contradictory requirements, a single organic platform fails to satisfy both of the operations simultaneously. In this work, a new approach was adopted to bring out synergy in dual functional activity by a single ionic-liquid-based platform, where new fluorogenic task-specific ionic liquids (TSILs) with the same cationic motif were used to derive both hydrophilic (TSIL1-3 with Br– anion) and hydrophobic ionic liquids (TSIL4-6 with NTf2– anion) for the dual functions. The hydrophilic ionic liquids were used for fluorescence sensing studies in a pure aqueous system, which shows selectivity for several metal ions (Cu2+, Fe3+, Pd2+, Ru3+, and Zn2+) with significantly lower limit of detection (LOD) values. The corresponding hydrophobic ionic liquids were used for bulk extraction studies with very high extraction efficiencies, which can be recycled easily. As an application, hydrophilic TSILs were used for biosensing of metal ions in living marine organisms like Artemia salina through in vivo bioimaging. The high affinity for ferric ion prompted us to evaluate the antibacterial activities of TSILs. The minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of the TSIL2 and TSIL3 show better antibacterial activity against eight pathogenic bacteria than the standard antibiotic ampicillin. This approach will be helpful in deriving dual applications of organic fluorophores with sustainability.