Sustainable Electro-Responsive Semi-Interpenetrating Starch/Ionic Liquid Copolymer Networks for the Controlled Sorption/Release of Biomolecules

Abstract

The main objective of this work was the development and characterization of sustainable electro-responsive ionic liquid-based cationic copolymers. For this purpose degradable semi-interpenetrating polymer networks (s-IPNs) based on starch and on ion-conducting cationic copolymers of 2-hydroxyethyl methacrylate (HEMA) and 1-butyl-3-vinylimidazolium chloride (BVImCl), cross-linked with N,N′-methylenebis­(acrylamide) (MBA), were synthesized by following principles of green chemistry. Cross-linked poly­(HEMA-co-BVImCl) copolymers were also prepared for comparison. The resulting cationic hydrogels (copolymer and s-IPNs) were characterized in terms of their physicochemical, thermomechanical, morphological, and electrochemical properties, as well as in terms of cell viability and proliferation against fibroblast cells. Furthermore, the electro-assisted sorption/release capacity of the prepared hydrogels toward l-tryptophan (used as a model biomolecule) was also studied at different applied DC voltages (0, 2, 5, and 100 V). Results demonstrated that the properties of the synthesized hydrogels can be tuned, depending on their relative chemical composition, presenting electronic conductivity and ionic conductivity values in the 0.1 to 5.2 S cm–1 range, and complex shear modulus in the 0.6 to 6.4 MPa range. The sorption/release capacity of the s-IPNs after 3 h at 25 °C can also be modulated between 2.5 and 70% and 4.5 and 40%, depending on the applied DC voltage and/or sorption/release medium. Finally, none of the synthesized cationic hydrogels induced fibroblast cells lysis, although s-IPNs had a lower impact on cell proliferation than poly­(HEMA-co-BVImCl) copolymers, indicating a favorable effect of starch on the biocompatibility of the synthesized s-IPNs. The designed cationic hydrogels could be useful for the development of efficient, stable, degradable and cheaper soft and multiresponsive platforms with potential applications in bioseparation processes, wastewater treatment systems (e.g., pharmaceutical), biomedical devices (e.g., sustained delivery of specific charged-biomolecules), and nonleaching electrochemical devices.

Green flexible electronics based on starch

“…However, it may be a risk when the usage of the starch-based FEs is large enough. The nondegradable components may be recycled by filtration or flotation Except for degradability, biocompatibility of the starchbased FEs was also concerned especially for medical applications, which can be confirmed through cytotoxicity tests 45,163 . The cell viability and the cell proliferation assays of the starch-based hydrogels were checked using Balb/3T3 fibroblasts cell in Kanaan's work (Fig.…”

“…Various sensors were fabricated on starch gels to obtain biocompatible devices 149,150 . Kanaan et al 45 synthesized a biodegradable semi-interpenetrating polymer networks (S-IPNs) based on starch and copolymer of 2-hydroxyethyl methacrylate (HEMA) and 1-butyl-3-metaprazor-lium chloride (BVImCl) cationic (Fig. 8b).…”

“…The amylose has a linear monomer at chain with only α-1,4 linkages thus possessing good extensibility in solution and can easily associate with some polar organic compounds by hydrogen bond. The amylopectin is the branch form with α-1,4 linkages in the backbone and α-1,6 linkages at the branched points, which usually has much higher molecular weight 45 . In addition, starch molecules contain lots of hydroxyl groups that are suitable for esterification 46 , etherification 47 , grafting 48 , cross-linking 49 , and other chemical modification 50,51 .…”

Environmentally Benign Natural Hydrogel Electrolyte Enables a Wide Operating Potential Window for Energy Storage Devices

“…The amylose is the linear part with α-1,4 linkages in the chain, has good extensibility in solution, and can readily bond by hydrogen bonding with polar chemical molecules. The amylopectin has a branched form and higher molecular weight with α-1,6 linkages in the branched parts and α-1,4 linkages at the backbone, , as well as the presence of plenty of −OH groups, which are beneficial for high proton conductivity in the presence of an external electrical field . Starch possesses the ability to gelatinize easily upon heating it in water at moderate temperatures (60–80 °C), where the hydrogen bonds between the starch molecules can be broken, dispersing in water to form a colloidal solution. , When the resultant solution becomes colder, the hydrogen bonds between the starch molecules are reformed and develop a three-dimensional network of a starch hydrogel via physical entanglement of amylose and/or amylopectin.…”

Designing Ionic Liquid-Derived Polymer Composites from Poly(Ionic Liquid)–Ionene Semi-interpenetrating Networks

“…X-ray scattering data indicated that the IPN adopted a lamellar structure while thermal analysis data supported the hypothesis that the resulting IPN was homogeneous. Since these initial findings, several other examples of IPNs and semi-IPNs have been reported, with a focus on tailoring the polymers toward specific applications such as gas separation, multi-responsive hydrogels, , and solid-state polymer electrolytes. − The most conductive networks from this group were found to be on the order of 10 –4 S/cm at 25 °C.…”