Molecularly Engineered Zwitterionic Hydrogels with High Toughness and Self-Healing Capacity for Soft Electronics Applications

Abstract

Zwitterionic hydrogels have attracted tremendous interest due to their densely charged network, ultralow fouling characteristics, and excellent biocompatibility. However, the unsatisfactory mechanical performance of the zwitterionic gels limits their practical applications. Here, we developed a new class of zwitterionic hydrogels from a structurally ameliorated sulfobetaine monomer, 3-(1-(4-vinylbenzyl)-1H-imidazol-3-ium-3-yl)propane-1sulfonate (VBIPS). The incorporated benzene and imidazole greatly enhance the tensile toughness and fracture toughness of the gel, which are 40 and 60 times higher than those of the conventional zwitterionic hydrogel, respectively. An obvious crack blunting occurs during the crack extension. In situ microscopic observation reveals that the outstanding toughness originates from the formation of a two-phase structure at room temperature, with an obvious contrast of the association energy. The mechanical properties of the gel can be well-tuned by changing the pH, and self-healing is achieved with an acid treatment. The VBIPS gel also possesses excellent short-term antifouling properties and the attached bacteria in a longer timescale can be easily released via salt treatment. To expand the application potentials, a VBIPS ionogel is prepared by soaking the gel in ionic liquids, which is flexible, antifreezing, and can be used as a strain sensor. This work provides a molecular strategy to toughen zwitterionic hydrogels, which should broaden their applications in diverse fields.

Bioinspired Hydrogels as Platforms for Life-Science Applications: Challenges and Opportunities

“…There is a variety of strategies to develop materials with properties attractive in many biomedical applications. Thus, the hydrogel strength can be tuned from their formulation, from very soft to very hard structure networks, suitable for the targeted applications: from injectable hydrogels [26,34,35] for tissue filling and restoration [3,[36][37][38], biomaterials for rapid hemostasis [39], wound healing [39,40], and drug delivery carriers [35,41] to robust and tough hydrogels required for load-bearing applications (artificial cartilage, muscle) [34] and smart biomaterials for tissue engineering [4,24,42] or advanced technological applications [14,43,44].…”

“…Many efforts were carried out to design and to characterize the performances of polymers and materials by triggering and tuning self-healing behavior, analysis of recovery properties and assessment of healing efficiency [10,12,14,[24][25][26][27][28][29]103,114,146,147,151,152,157,165]. The hydrogels can be used as biomimetic systems for understanding the complex cells behavior to various microenvironments.…”

“…From a chemical point of view, the hydrogels can be obtained from natural or synthetic water soluble (co)polymers of various structures and architectures, interpenetrated polymer networks (IPNs), proteins, peptides, clays, multicomponent systems, etc., having different morphologies and functions [1][2][3]. In particular, smart networks able to respond to physical, chemical, and biological stimuli gained much attention for a wide range of applications: tissue engineering [4], bone regeneration [5], controlled-release drug delivery vehicles [6], wound healing [7], soft robotics [8], biosensing [9], intelligent electronics and artificial intelligence [10], actuators [11][12][13], stretched electronic devices [14], hygiene products [15,16], contact lens [17], cosmetics [18], food nutrition and health, food safety and food engineering and processing [19], advanced wastewater treatment [20], catalysis [21][22][23], etc.…”

An Overview on Recent Progress of the Hydrogels: From Material Resources, Properties, to Functional Applications

“…[46] Additionally, by reducing diffusion of matrix metal precursors in the solution, metal nanoparticles can also be loaded in the preparation of hydrogels. [47][48][49] Hydrogel nanocomposite materials consists of polymer hydrogels and organic nanoparticles embedded in the hydrogel matrixes, [48,[50][51][52][53] which have attracted great attention owing to their distinctive inorganic and organic hybrid structures and the excellent mechanical properties in aspects of elasticity, [54,55] toughness, [56][57][58] viscosity, [59,60] and so on. In the process of hydrogels (the conversion of low viscosity solution to hydrogels), technologies such as microfluidic are allowed to prepare hydrogels with arbitrary geometry.…”

Facile preparation of a thermosensitive and antibiofouling physically crosslinked hydrogel/powder for wound healing

“…Therefore, the ideal antibacterial hydrogel should be able to prevent bacterial adhesion in the initial stage, and then exhibit the effectiveness of killing the attached bacteria, and finally automatically release the dead bacteria. 30,31 A zwitterionic poly(sulfobetaine methacrylate) (PSBMA) based hydrogel can effectively resist the non-specific adhesion of various proteins and bacteria owing to its super hydrophilic properties, 32 which has been widely used in cell expansion culture, 33 anti-coagulation coating, 34,35 postoperative anti-adhesion, 36,37 antibacterial wound dressing, 38 etc. Chitosan-based hydrogels also have been widely used in the biomedical field due to their excellent biocompatibility, biodegradability, and good ability to kill bacteria.…”