Synthesis of Biocompatible Aliphatic Terpolymers via In Situ Fluorescent Monomers for Three-in-One Applications: Polymerization of Hydrophobic Monomers in Water.

Biocompatible, nonconventional, multifunctional, purely aliphatic, light-emitting terpolymers, i.e., acrylonitrile--3-(-isopropylacrylamido)propanenitrile---isopropylacrylamide (AN--NIPAMPN--NIPA, ) and acrylonitrile--3-(-hydroxymethylacrylamido)propanenitrile---hydroxymethylacrylamide (AN--NHMAMPN--NHMA, ), were designed and synthesized via N-H-functionalized C-C + N-C-coupled in situ protrusions/grafting of fluorophore monomers, i.e., NIPAMPN and NHMAMPN, by solution polymerization of highly hydrophobic nonemissive monomers in water. These scalable and reusable and were suitable for high-performance three-in-one applications, such as Fe(III) sensors, imaging of Madin-Darby canine kidney (MDCK) and human lung cancer (A549) cells, and security inks. The structures of and , N-C-coupled in situ attachments/grafting of fluorophore monomers, grafting events, and aggregation-enhanced emissions (AEEs), were analyzed by H and C NMR spectroscopy, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, ultraviolet-visible (UV-vis) spectroscopy, thermogravimetric (TG) analysis, high-resolution transmission electron microscopy (HRTEM), dynamic light scattering (DLS), fluorescence imaging, and fluorescence lifetime. The geometries, electronic structures, and absorption/emission properties of and at optimized compositions were examined by density functional theory (DFT), time-dependent DFT (TDDFT), and natural transition orbital (NTO) analyses. The limits of detection were 3.20 × 10 and 1.37 × 10 M for and , respectively. The excellent biocompatibility of and was confirmed by >95% retention of MDCK and A549 cell morphologies.