Gradient biomimetic platforms for neurogenesis studies.

There is a need for the development of new cellular therapies for the treatment of many diseases, with the central nervous system (CNS) currently an area of specific focus. Due to the complexity and delicacy of its biology, there is currently a limited understanding of neurogenesis and consequently a lack of reliable test platforms, resulting in several CNS based diseases having no cure. The ability to differentiate pluripotent stem cells into specific neuronal sub-types may enable scalable manufacture for clinical therapies, with a focus also on the purity and quality of the cell population.

Digitally Driven Aerosol Jet Printing to Enable Customisable Neuronal Guidance.

Digitally driven manufacturing technologies such as aerosol jet printing (AJP) can make a significant contribution to enabling new capabilities in the field of tissue engineering disease modeling and drug screening. AJP is an emerging non-contact and mask-less printing process which has distinct advantages over other patterning technologies as it offers versatile, high-resolution, direct-write deposition of a variety of materials on planar and non-planar surfaces. This research demonstrates the ability of AJP to print digitally controlled patterns that influence neuronal guidance.

Bioengineered model of the human motor unit with physiologically functional neuromuscular junctions.

Investigations of the human neuromuscular junction (NMJ) have predominately utilised experimental animals, model organisms, or monolayer cell cultures that fail to represent the physiological complexity of the synapse. Consequently, there remains a paucity of data regarding the development of the human NMJ and a lack of systems that enable investigation of the motor unit. This work addresses this need, providing the methodologies to bioengineer 3D models of the human motor unit.

Physiological and pathophysiological concentrations of fatty acids induce lipid droplet accumulation and impair functional performance of tissue engineered skeletal muscle.

Fatty acids (FA) exert physiological and pathophysiological effects leading to changes in skeletal muscle metabolism and function, however, in vitro models to investigate these changes are limited. These experiments sought to establish the effects of physiological and pathophysiological concentrations of exogenous FA upon the function of tissue engineered skeletal muscle (TESkM). Cultured initially for 14 days, C2C12 TESkM was exposed to FA-free bovine serum albumin alone or conjugated to a FA mixture (oleic, palmitic, linoleic, and α-linoleic acids [OPLA] [ratio 45:30:24:1%]) at different concentrations (200 or 800 µM) for an additional 4 days.

3D-printable zwitterionic nano-composite hydrogel system for biomedical applications.

Herein, the cytotoxicity of a novel zwitterionic sulfobetaine hydrogel system with a nano-clay crosslinker has been investigated. We demonstrate that careful selection of the composition of the system (monomer to Laponite content) allows the material to be formed into controlled shapes using an extrusion based additive manufacturing technique with the ability to tune the mechanical properties of the product. Moreover, the printed structures can support their own weight without requiring curing during printing which enables the use of a printing-then-curing approach.

Mechanical loading of tissue engineered skeletal muscle prevents dexamethasone induced myotube atrophy.

Skeletal muscle atrophy as a consequence of acute and chronic illness, immobilisation, muscular dystrophies and aging, leads to severe muscle weakness, inactivity and increased mortality. Mechanical loading is thought to be the primary driver for skeletal muscle hypertrophy, however the extent to which mechanical loading can offset muscle catabolism has not been thoroughly explored. In vitro 3D-models of skeletal muscle provide a controllable, high throughput environment and mitigating many of the ethical and methodological constraints present during in vivo experimentation.

Differentiation of Bioengineered Skeletal Muscle within a 3D Printed Perfusion Bioreactor Reduces Atrophic and Inflammatory Gene Expression.

Bioengineered skeletal muscle tissues benefit from dynamic culture environments which facilitate the appropriate provision of nutrients and removal of cellular waste products. Biologically compatible perfusion systems hold the potential to enhance the physiological biomimicry of in vitro tissues via dynamic culture, in addition to providing technological advances in analytical testing and live cellular imaging for analysis of cellular development. To meet such diverse requirements, perfusion systems require the capacity and adaptability to incorporate multiple cell laden constructs of both monolayer and bioengineered tissues.

Development of a 3D Tissue-Engineered Skeletal Muscle and Bone Co-culture System.

In vitro 3D tissue-engineered (TE) structures have been shown to better represent in vivo tissue morphology and biochemical pathways than monolayer culture, and are less ethically questionable than animal models. However, to create systems with even greater relevance, multiple integrated tissue systems should be recreated in vitro. In the present study, the effects and conditions most suitable for the co-culture of TE skeletal muscle and bone are investigated.

Functional regeneration of tissue engineered skeletal muscle in vitro is dependent on the inclusion of basement membrane proteins.

Skeletal muscle has a high regenerative capacity, injuries trigger a regenerative program which restores tissue function to a level indistinguishable to the pre-injury state. However, in some cases where significant trauma occurs, such as injuries seen in military populations, the regenerative process is overwhelmed and cannot restore full function. Limited clinical interventions exist which can be used to promote regeneration and prevent the formation of non-regenerative defects following severe skeletal muscle trauma.

Mechanical loading stimulates hypertrophy in tissue-engineered skeletal muscle: Molecular and phenotypic responses.

Mechanical loading of skeletal muscle results in molecular and phenotypic adaptations typified by enhanced muscle size. Studies on humans are limited by the need for repeated sampling, and studies on animals have methodological and ethical limitations. In this investigation, three-dimensional skeletal muscle was tissue-engineered utilizing the murine cell line C2C12, which bears resemblance to native tissue and benefits from the advantages of conventional in vitro experiments.

Scalable 3D Printed Molds for Human Tissue Engineered Skeletal Muscle.

Tissue engineered skeletal muscle allows investigation of the cellular and molecular mechanisms that regulate skeletal muscle pathology. The fabricated model must resemble characteristics of tissue and incorporate cost-effective and high content primary human tissue. Current models are limited by low throughput due to the complexities associated with recruiting tissue donors, donor specific variations, as well as cellular senescence associated with passaging.

Polydimethylsiloxane and poly(ether) ether ketone functionally graded composites for biomedical applications.

Functionally graded materials (FGMs), with varying spatial, chemical and mechanical gradients (continuous or stepwise), have the potential to mimic heterogenous properties found across biological tissues. They can prevent stress concentrations and retain healthy cellular functions. Here, we show for the first time the fabrication of polydimethylsiloxane and poly(ether) ether ketone (PDMS-PEEK) composites.

Controlled Arrangement of Neuronal Cells on Surfaces Functionalized with Micropatterned Polymer Brushes.

Conventional in vitro cultures are useful to represent simplistic neuronal behavior; however, the lack of organization results in random neurite spreading. To overcome this problem, control over the directionality of SH-SY5Y cells was attained, utilizing photolithography to pattern the cell-repulsive anionic brush poly(potassium 3-sulfopropyl methacrylate) (PKSPMA) into tracks of 20, 40, 80, and 100 μm width. These data validate the use of PKSPMA brush coatings for a long-term culture of the SH-SY5Y cells, as well as providing a methodology by which the precise deposition of PKSPMA can be utilized to achieve a targeted control over the SH-SY5Y cells.

Feasibility and Biocompatibility of 3D-Printed Photopolymerized and Laser Sintered Polymers for Neuronal, Myogenic, and Hepatic Cell Types.

The integration of additive manufacturing (AM) technology within biological systems holds significant potential, specifically when refining the methods utilized for the creation of in vitro models. Therefore, examination of cellular interaction with the physical/physicochemical properties of 3D-printed polymers is critically important. In this work, skeletal muscle (C C ), neuronal (SH-SY5Y) and hepatic (HepG2) cell lines are utilized to ascertain critical evidence of cellular behavior in response to 3D-printed candidate polymers: Clear-FL (stereolithography, SL), PA-12 (laser sintering, LS), and VeroClear (PolyJet).

An Assessment of Myotube Morphology, Matrix Deformation, and Myogenic mRNA Expression in Custom-Built and Commercially Available Engineered Muscle Chamber Configurations.

There are several three-dimensional (3D) skeletal muscle (SkM) tissue engineered models reported in the literature. 3D SkM tissue engineering (TE) aims to recapitulate the structure and function of native () tissue, within an environment. This requires the differentiation of myoblasts into aligned multinucleated myotubes surrounded by a biologically representative extracellular matrix (ECM).

Neural and Aneural Regions Generated by the Use of Chemical Surface Coatings.

The disordered environment found in conventional neural cultures impedes various applications where cell directionality is a key process for functionality. Neurons are highly specialized cells known to be greatly dependent on interactions with their surroundings. Therefore, when chemical cues are incorporated on the surface material, a precise control over neuronal behavior can be achieved.

Biocompatible 3D printed polymers via fused deposition modelling direct CC cellular phenotype in vitro.

The capability to 3D print bespoke biologically receptive parts within short time periods has driven the growing prevalence of additive manufacture (AM) technology within biological settings, however limited research concerning cellular interaction with 3D printed polymers has been undertaken. In this work, we used skeletal muscle CC cell line in order to ascertain critical evidence of cellular behaviour in response to multiple bio-receptive candidate polymers; polylactic acid (PLA), acrylonitrile butadiene styrene (ABS), polyethylene terephthalate (PET) and polycarbonate (PC) 3D printed via fused deposition modelling (FDM). The extrusion based nature of FDM elicited polymer specific topographies, within which CC cells exhibited reduced metabolic activity when compared to optimised surfaces of tissue culture plastic, however assay viability readings remained high across polymers outlining viable phenotypes.

3D printed fluidics with embedded analytic functionality for automated reaction optimisation.

Additive manufacturing or '3D printing' is being developed as a novel manufacturing process for the production of bespoke micro- and milliscale fluidic devices. When coupled with online monitoring and optimisation software, this offers an advanced, customised method for performing automated chemical synthesis. This paper reports the use of two additive manufacturing processes, stereolithography and selective laser melting, to create multifunctional fluidic devices with embedded reaction monitoring capability.

Design and additive manufacture for flow chemistry.

We review the use of additive manufacturing (AM) as a novel manufacturing technique for the production of milli-scale reactor systems. Five well-developed additive manufacturing techniques: stereolithography (SL), multi-jet modelling (MJM), selective laser melting (SLM), laser sintering (LS) and fused deposition modelling (FDM) were used to manufacture a number of miniaturised reactors which were tested using a range of organic and inorganic reactions.