Soft-ionic materials with biocompatibility and 3D printability are needed to develop next-generation devices to interface between electronic and biological signals. Herein, thermoreversible and biocompatible ionic liquid gels or iongels, which can be processed by direct ink writing are reported. The iongels are designed by taking advantage of polyvinyl alcohol/phenol interactions to gelify biocompatible cholinium carboxylate ionic liquids. The obtained iongels are stable, soft, and flexible materials (Young modulus between 14 and 70 kPa) with high ionic conductivity (1.8 × 10–2 S cm–1). Interestingly, they presented thermoreversible properties with gel–sol transitions ranging from 85 and 110 °C, which allows the iongel…
Biofabrication techniques such as microlithography and 3-D bioprinting have emerged in recent years as technologies capable of rendering complex, biocompatible constructs for biosensors, tissue and regenerative engineering and bioelectronics. While instruments and processes have been the subject of immense advancement, multifunctional bioinks have received less attention. A novel photocrosslinkable, hybrid bioactive and inherently conductive bioink formed from poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) nanomaterials within poly(2-hydroxyethyl methacrylate-co-polyethyleneglycol methacrylate) p(HEMA-co-EGMA) was used to render complex hydrogel constructs through microlithographic fabrication and 3-D printing. Constructs were directly compared through established metrics of acuity and fidelity, using side-by-side comparison of microarray grids, triangles incorporating angles 15–90°,…
The ability of boronic acids (BAs) to reversibly bind diols, such as sugars, has been widely studied in recent years. In solution, through the incorporation of additional fluorophores, the BA–sugar interaction can be monitored by changes in fluorescence. Ultimately, a practical realization of this technology requires a transition from solution‐based methodologies. Herein, the first example of 3D‐printed sugar‐sensing hydrogels, achieved through the incorporation of a BA–fluorophore pair in a gelatin methacrylamide‐based matrix is presented. Through optimization of monomeric cocktails, it is possible to use extrusion printing to generate structured porous hydrogels which show a measurable and reproducible linear fluorescence response…
Over the last decays, the use of conductive biopolymer composites has been growing in areas such as biosensors, soft robotics, and wound dressing applications. They are generally soft hydrophilic materials with good elastic recovery and compatible with biological environments. However, their application and removal from the host are still challenging mainly due to poor mechanical strength. This work displays a technique for the fabrication of complex‐shaped conductive structures with improved mechanical strength by wet three‐dimensional (3‐D) printing, which uses a coagulation bath to quickly solidify an epoxy cross‐linked chitosan/carbon microtube composite ink. The fabricated conductive structure demonstrated higher elongation strength…
Soft tissue fixation of implant and bioelectrodes relies on mechanical means (e.g., sutures, staples, and screws), with associated complications of tissue perforation, scarring, and interfacial stress concentrations. Adhesive bioelectrodes address these shortcomings with voltage cured carbene‐based bioadhesives, locally energized through graphene interdigitated electrodes. Electrorheometry and adhesion structure activity relationships are explored with respect to voltage and electrolyte on bioelectrodes synthesized from graphene 3D‐printed onto resorbable polyester substrates. Adhesive leachates effects on in vitro metabolism and human‐derived platelet‐rich plasma response serves to qualitatively assess biological response. The voltage activated bioadhesives are found to have gelation times of 60 s or less…