Perylene bisimides (PBIs) with high quantum yields and high chemical and photophysical stabilities are usually suffering from poor solubility in various solvents, including water, which restricts their use in biomedical and other applications. Thus, in this study, as-synthesized hydrophilic poly(1-vinylimidazole) (PVim) is introduced at both the imide positions of the hydrophobic PBI unit by using L-cysteine (Cys) bearing two orthogonally reactive groups to produce a water-and organicsoluble PBI-based polymer conjugate. To do so, first, L-cysteine is used for thiol-mediated radical polymerization of 1-vinylimidazole (Vim). In the next step, the cysteine-end-capped poly(1-vinylimidazole) (Cys−PVim) with free −NH 2 is coupled with perylene-3,4,9,10-tetracarboxylic dianhydride (PDA) by employing a onestep microwave-assisted reaction to produce PBI−(Cys−PVim) 2 conjugate. The solution optical properties of this conjugate are thoroughly investigated to ascertain the extent of aggregation among PBIs units in both aqueous and organic media. The aqueous PBI−(Cys−PVim) 2 solution emits characteristic green fluorescence of PBI under UV irradiation of 365 nm wavelength. Owing to the presence of a protonable imidazole moiety, the PBI−(Cys−PVim) 2 conjugate shows pH-dependent optical properties. The amphiphilic PBI−(Cys−PVim) 2 molecules undergo self-assembly into vesicular nanostructures in water as confirmed from cryo-and high-resolution-transmission electron microscopy. The conjugate binds with ctDNA and plasmid DNA in water to form polyplexes. The fluorescent PBI−(Cys−PVim) 2 conjugate with low cytotoxicity and high quantum yield is efficiently used for the imaging of HeLa cells. The cellular uptake of the conjugate is studied at different time intervals and at different pHs using fluorescence microscopy.

The use of polymer gels for the removal of toxic chemicals from wastewater is an important area in terms of both academic and industrial research. This work presents a simple approach to the fabrication of chemically cross-linked cationic hydrogel adsorbents using designed ionic liquid-based cross-linkers and their successful use in the removal of organic dyes. Two different ionic liquid cross-linkers, [VIm-4VBC]­[Cl] (ILA)/[DMAEMA-4VBC]­[Cl] (ILB), are synthesized by the simple nucleophilic substitution reaction of 4-vinylbenzyl chloride (4VBC) separately with 1-vinylimidazole (VIm) and 2-(dimethylamino)­ethyl methacrylate (DMAEMA). Cross-linked poly­(acrylamide) (CPAam) and poly­(2-hydroxyethyl methacrylate) (CPHEMA) hydrogels are then prepared from the corresponding monomers and as-synthesized cross-linkers (ILA and ILB) by free radical polymerization in the presence of a redox initiator combining ammonium persulfate (APS) and N,N,N′,N′-tetra­methyl­ethylene­diamine (TEMED). The dried CPAam and CPHEMA xerogels exhibit macroporous morphology and high thermal stability. The hydrogel samples exhibit high swelling behavior, and the diffusion of water molecules into the hydrogels follows pseudo-Fickian kinetics. The cationic cross-linking sites in the hydrogel networks allow preferable binding with anionic dyes, and these dye uptake capacities are determined using different model anionic dyes via UV–vis spectroscopy. The dye adsorption onto these hydrogels follows a pseudo-second-order kinetic model. The adsorption mechanism is also analyzed by employing intraparticle diffusion and Boyd kinetic models. The relationship between the maximum equilibrium adsorption capacity (q m) of the hydrogels for eosin B (EB) dye and the equilibrium EB concentration can be better described by Langmuir and Freundlich isotherm models, and the estimated q m using the Langmuir isotherm can reach more than 100 mg g–1. The cross-linked hydrogels can be easily regenerated and have a recycling efficiency of >80% for up to three consecutive dye adsorption–desorption cycles, which is promising for their use in wastewater treatment.

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Cationic polypeptides based smart biomaterials offer immense potential for biomedical applications including the field of delivery of drugs and capability to spontaneously bind to the biologically active components such as...

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