Flexible piezoelectric generators (PEGs) present a unique opportunity for renewable and sustainable energy harvesting. Here, we present a low-temperature and low-energy deposition method using solvent evaporation-assisted three-dimensional printing to deposit electroactive poly(vinylidene fluoride) (PVDF)-trifluoroethylene (TrFE) up to 19 structured layers. Visible-wavelength transmittance was above 92%, while ATR-FTIR spectroscopy showed little change in the electroactive phase fraction between layer depositions. Electroactivity from the fabricated PVDF-TrFE PEGs showed that a single structured layer gave the greatest output at 289.3 mV peak-to-peak voltage. This was proposed to be due to shear-induced polarization affording the alignment of the fluoropolymer dipoles without an electric field…
Low-concentration hydrogels have favorable properties for many cell functions in tissue engineering but are considerably limited from a scaffold fabrication point of view due to poor three-dimensional (3D) printability. Here, we developed an indirect-bioprinting process for alginate scaffolds and characterized the potential of these scaffolds for nerve tissue engineering applications. The indirect-bioprinting process involves (1) printing a sacrificial framework from gelatin, (2) impregnating the framework with low-concentration alginate, and (3) removing the gelatin framework by an incubation process, thus forming low-concentration alginate scaffolds. The scaffolds were characterized by compression testing, swelling, degradation, and morphological and biological assessment of incorporated or…
Information from the brain travels back and forth along peripheral nerves in the form of electrical impulses generated by neurons and these impulses have repetitive patterns. Schwann cells in peripheral nerves receive molecular signals from axons to coordinate the process of myelination. There is evidence, however, that non-molecular signals play an important role in myelination in the form of patterned electrical impulses generated by neuronal activity. The role of patterned electrical impulses has been investigated in the literature using co-cultures of neurons and myelinating cells. The co-culturing method, however, prevents the uncoupling of the direct effect of patterned electrical impulses…
3D printing provides a novel approach to repair bone defects using customized biomimetic tissue scaffolds. To make a bone substitute closest to natural bone structure and composition, two different types of hydroxyapatite, Nano hydroxyapatite (nHA) and deproteinized bovine bone (DBB), were dispersed into collagen (CoL) to prepare the bio-ink for 3D printing. In doing so, a porous architecture was manufactured with 3D printing technology. The physical and chemical properties of the materials were evaluated, including biocompatibility and effect on the osteogenic differentiation of the human bone marrow-derived mesenchyme stem cells (hBMSCs). The XPS, XRD, FTIR, and the mechanical analysis of…
Recent advances in 3D printing have enabled the fabrication of interesting structures which were not achievable using traditional fabrication approaches. 3D printing of carbon microtube composite inks allows fabrication of conductive structures for practical applications in soft robotics and tissue engineering. However, it is challenging to achieve 3D printed structures from solution‐based composite inks which requires an additional process to solidify the ink. Here, we introduce a wet 3D printing technique which uses a coagulation bath to fabricate carbon microtube composite structures. We show that through facile nanogrooving approach which introduces cavitation and channels on carbon microtubes, enhanced interfacial interactions…
Introduction of 3-dimensional (3D) printing in fabrication and increasing applications of intriguing products in soft robotics have led to studies on controllable 3D printed soft actuators. Therefore, a demand for a precise and computationally efficient model for bending control of the 3D printed soft actuators has arisen. This study initially used a grey box strategy for dynamic modeling of a 3D printed soft actuator which undergoes large bending deformations. Yet, the primary model estimated results deviated from experimental results due to uncertainties such as hysteresis and time varying characteristics of the soft actuator in presence of electric field. Thus, a…
Peripheral nerve tissue requires appropriate biochemical and physical cues to guide the regeneration process after injury. Bioprinted peptide-conjugated sodium alginate (PCSA) scaffolds have the potential to provide physical and biochemical cues simultaneously. Such scaffolds need characterisation in terms of printability, mechanical stability, and biological performance to refine and improve application in nerve tissue regeneration. In this study, it was hypothesized that 3D scaffold printed with low concentrated multiple PCSA precursor would be supportive for axon outgrowth. Therefore, a 2% (w/v) alginate precursor was conjugated with either arginine-glycine-aspartate (RGD) or tyrosine-isoleucine-glycine-serine-arginine (YIGSR) peptides, or a mixture of RGD and YIGSR (1:2)…
Porous scaffolds were 3D-printed using poly lactic-co-glycolic acid (PLGA)/TiO2 composite (10:1 weight ratio) for bone tissue engineering applications. Addition of TiO2 nanoparticles improved the compressive modulus of scaffolds. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) revealed an increase in both glass transition temperature and thermal decomposition onset of the composite compared to pure PLGA. Furthermore, addition of TiO2 was found to enhance the wettability of the surface evidenced by reducing the contact angle from 90.5 ± 3.2 to 79.8 ± 2.4 which is in favor of cellular attachment and activity. The obtained results revealed that PLGA/TiO2 scaffolds significantly improved osteoblast proliferation compared to…
A key challenge towards engineering 3D printed soft tissues is the availability of proper scaffolding materials with enough load carrying capacity. In this study, we synthesized biocompatible and biodegradable, elastomeric polyurethaneureas (TPUU) and investigated the applicability of these novel materials as 3D printed load carrying constructs.
The presence and progression of neuromuscular pathology, including spasticity, Duchenne’s muscular dystrophy and hyperthyroidism, has been correlated with changes in the intrinsic mechanical properties of skeletal muscle tissue. Tools for noninvasively measuring and monitoring these properties, such as Magnetic Resonance Elastography (MRE), could benefit basic research into understanding neuromuscular pathologies, as well as translational research to develop therapies, by providing a means of assessing and tracking their efficacy. Dynamic elastography methods for noninvasive measurement of tissue mechanical properties have been under development for nearly three decades. Much of the technological development to date, for both Ultrasound (US)-based and Magnetic Resonance…