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Engineering skeletal muscle tissue is crucial for the repair and replacement of damaged or dysfunctional muscle. Despite numerous studies emphasizing the significance of skeletal muscle engineering, challenges persist in effectively replacing or repairing large muscle sections in vivo. Bioreactors that facilitate the rapid expansion of muscle precursor cells present a promising solution for addressing extensive muscle loss. Specifically, bioreactors that mimic the native microenvironment of muscle tissue can induce biomimetic stimuli, selectively promoting the expansion of muscle precursors with optimal myo‐regenerative potential. In this review, the advancements made in utilizing bioreactors to enhance the myo‐regenerative phenotype of cells for skeletal muscle engineering are highlighted. [ABSTRACT FROM AUTHOR]

A major obstacle toward creating human‐scale artificial tissue models is supplying encapsulated cells with oxygen and other nutrients throughout the construct. In particular, creating channels in hydrogels that match the resolution and density of the smallest blood capillaries (≤10 µm) remains highly challenging. Here, a novel method is demonstrated where polycaprolactone fibers printed using melt‐electrowriting are encapsulated in cell‐laden hydrogels and then physically removed to produce hollow, perfusable channels. This technique produces a range of channel diameters (10–41 µm) with circular cross‐sections and in hydrogels representing various crosslinking mechanisms. The channels can be formed as interconnected grids, hierarchically branched patterns, or stacked in layers with ≈200 µm channel spacing, thus matching average capillary density in the human body. Alternatively, selective removal of fibers from a melt electrowriting grid can generate perfusable channels within a reinforcing fiber network. This method can be performed in the presence of cells, with human fibroblasts exhibiting encapsulated in gelatin methacryloyl showing no detectable cytotoxic effects. This technique is a promising approach for creating perfusable channels with very small diameters within cell‐laden hydrogel matrices, with potential applications including in vitro tissue models and hydrogel microfluidics. [ABSTRACT FROM AUTHOR]

Extrusion printing techniques are widely used across tissue engineering and related fields for producing 3D structures from biocompatible thermoplastics, however the achievable structural complexity and porosity can be limited by the nozzle‐based, layer‐by‐layer deposition process. Here, how this limitation can be overcome through a new technique termed Negative Embodied Sacrificial Template 3D printing is illustrated. It is demonstrated how the negative pattern within a 3D printed object can easily describe geometries that are extremely challenging to extrusion print directly with biomaterials, and at high resolution. Negative patterns in a water‐soluble sacrificial template can be "developed" by casting in a secondary material and dissolving the template, creating exquisitely complex 3D structures including hyper‐branched dendritic structures and open lattices with stiffnesses tuneable over 3 orders of magnitude. The technique is amenable to a plethora of materials from biodegradable thermoplastics (such as polycaprolactone) to resins (including acrylic and epoxy), silicones (including the Sylgard 184 polydimethylsiloxane formulation), ceramics (including hydroxyapatite composites), hydrogels (including agarose and gelatin methacryloyl), low‐melt temperature metal alloys and others. Using an unmodified, consumer‐grade printer, NEST3D printing achieves high resolution, intricate biomaterial structures with potential applications in biomedical implants and tissue engineering scaffolds. [ABSTRACT FROM AUTHOR]

The electrochemical sensing of clonazepam in samples of unprocessed saliva is reported, using commercially available reduced graphene oxide (rGO) screen printed electrodes (SPEs). The rGO electrodes were modified with self‐assembled lubricin (LUB) antiadhesive coatings that function as a size‐selective molecular sieve that partitions small molecule analytes from large fouling molecules at the electrode‐fluid interface. By mitigating the adverse effects of protein fouling, these LUB coatings enable direct, reliable, and quantitative electrochemical measurements of clonazepam concentrations in untreated saliva, which was not possible with uncoated rGO electrodes in identical tests. The proposed assay design, which is suitable for disposable point‐of‐care diagnostics requires no sample pre‐treatment and shows a linear detection response over a concentration range of 25–250 nM with a correlation coefficient of R2=0.987 and a limit of detection (LoD) of 16.67 nM. The swab‐based sample acquisition method paired with the antifouling properties of the LUB coatings provide a cost effective and practical biosensing platform for assessing electroactive drug concentrations in saliva in a point‐of‐care setting. [ABSTRACT FROM AUTHOR]

Biofouling on surfaces compromises the function of biomedical devices whose function involves contact with biological fluids. In the context of electrochemical devices, proteins are attracted to the surface via coaction of various forces (hydrogen bond, hydrophobic effect, and other polar interactions) and protein interaction with the surface can significantly alter the surface chemistry. In response to this issue, we have developed an efficient anti‐biofouling surface that employs a glycoprotein, lubricin (LUB), and which generates low impedance layers compatible with electrochemical applications. Herein, we investigate how different LUB densities on platinum (Pt) electrodes affect the surface electrochemistry and its ability to prevent nonspecific adsorption of protein to the surface. Surfaces with higher densities of LUB were more resistant to protein adsorption. The LUB modified Pt electrodes were challenged in artificial perilymph (AP) media under passive and electrically stimulated conditions over 7‐day periods throughout which the LUB layer retained its anti‐biofouling and surface coating stability. LUBed up: a low‐impedance protein‐resistant surface is introduced, that consists of lubricin (LUB) coating onto a platinum surface. The LUB‐platinum interface presents a good resistance to nonspecific protein adsorption, remaining stable on the surface under passive or electrical‐stimulated conditions. [ABSTRACT FROM AUTHOR]

In the current study, we describe the synthesis, material characteristics, and cytocompatibility of conducting poly (ɛ-caprolactone) (PCL)-based nano-composite films. Electrically conducting carbon nano-fillers (carbon nano-fiber (CNF), nano-graphite (NG), and liquid exfoliated graphite (G)) were used to prepare porous film type scaffolds using modified solvent casting methods. The electrical conductivity of the nano-composite films was increased when carbon nano-fillers were incorporated in the PCL matrix. CNF-based nano-composite films showed the highest increase in electrical conductivity. The presence of an ionic solution significantly improved the conductivity of some of the polymers, however at least 24 h was required to absorb the simulated ion solutions. CNF-based nano-composite films were found to have good thermo-mechanical properties compared to other conducting polymer films due to better dispersion and alignment in the critical direction. Increased nano-filler content increased the crystallisation temperature. Analysis of cell viability revealed no increase in cell death on any of the polymers compared to tissue culture plastic controls, or compared to PCL polymer without nano-composites. The scaffolds showed some variation when tested for PC12 cell attachment and proliferation, however all the polymers supported PC12 attachment and differentiation in the absence of cell adhesion molecules. In general, CNF-based nano-composite films with highest electrical conductivity and moderate roughness showed highest cell attachment and proliferation. These polymers are promising candidates for use in neural applications in the area of bionics and tissue engineering due to their unique properties. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 853-865, 2016. [ABSTRACT FROM AUTHOR]