Dissolvable 3D printed PVA moulds for melt electrowriting tubular scaffolds with patient-specific geometry

Over the past decade, melt electrowriting (MEW) has established the fundamental understanding of processing (and printer) requirements. Iterative work on parametric development and dissemination of this recent additive manufacturing technology has been performed across many systems and polymers (mainly poly-(𝝐-caprolactone)), showing similarities and trends. However, the software and hardware ecosystems of MEW are not mature. Further, due to its multi-parametric nature, MEW can be challenging for laboratories to master. This review intends to provide a unique perspective on the dynamic relationship between MEW processing parameters. Such parameters can be divided into 1) those that affect the polymer flow rate to or 2) from the nozzle, and 3) environmental conditions. The most influential parameters for high-quality printing are applied voltage, applied pressure, collector speed, polymer temperature, nozzle diameter, and the conditions that lead to charge buildup (e.g., relative humidity). Other factors such as ambient temperature, nozzle size, and protrusion, collector temperature and conductivity, and collector distance can all affect the process. Success for MEW printing means fibers fall onto the collector according to their pre-programmed path with predicted fiber diameter. Here, the authors elucidate how the dynamic relationship between these parameters can converge into ideal printing conditions to produce scaffolds.

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“…These features can be dissolvable so that, once the print has been made, the feature is removed and the MEW structure obtained. [ 36 ]…”

Section: A Mew Handbook: Exploring the Relationships Between Processi...mentioning

confidence: 99%

A Decade of Melt Electrowriting

O'Neill

Dalton

2023

Small Methods

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“…While future SPAs should integrate patient-specific hollow channels to form vessels and medium perfusion for shear stress, improved soft actuator cell culture substrates that mimic the stiffness and elasticity of vascular ECM are critical for accurately replicating soft tissue mechanics and inducing physiologically relevant tissue remodeling during conditioning regimens [58,59]. For example, advanced additive manufacturing methods could be used to fabricate perfusable patient-specific actuators from sacrificial 3D printed molds while incorporating hydrogel and melt electrowritten scaffold substrates to emulate soft tissue viscoelasticity more closely [60,61]. Furthermore long-term culture is necessary to fully mature and assess biomanufactured vessels, and the functional effects of mechanical preconditioning must be validated by preclinical grafting and drug response experiments.…”

Section: Multi-axial Mechanical Preconditioning For Future Tissue Bio...mentioning

confidence: 99%

Soft pneumatic actuators for mimicking multi-axial femoropopliteal artery mechanobiology

Fell¹,

Brooks-Richards²,

Woodruff³

et al. 2022

Biofabrication

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Tissue biomanufacturing aims to produce lab-grown stem cell grafts and biomimetic drug testing platforms but remains limited in its ability to recapitulate native tissue mechanics. The emerging field of soft robotics aims to emulate dynamic physiological locomotion, representing an ideal approach to recapitulate physiologically complex mechanical stimuli and enhance patient-specific tissue maturation. The kneecap’s femoropopliteal artery (FPA) represents a highly flexible tissue across multiple axes during blood flow, walking, standing, and crouching positions, and these complex biomechanics are implicated in the FPA’s frequent presentation of peripheral artery disease. We developed a soft pneumatically actuated (SPA) cell culture platform to investigate how patient-specific FPA mechanics affect lab-grown arterial tissues. Silicone hyperelastomers were screened for flexibility and biocompatibility, then additively manufactured into SPAs using a simulation-based design workflow to mimic normal and diseased FPA extensions in radial, angular, and longitudinal dimensions. SPA culture platforms were seeded with mesenchymal stem cells, connected to a pneumatic controller, and provided with 24-hour multi-axial exercise schedules to demonstrate the effect of dynamic conditioning on cell alignment, collagen production, and muscle differentiation without additional growth factors. Soft robotic bioreactors are promising platforms for recapitulating patient-, disease-, and lifestyle-specific mechanobiology for understanding disease, treatment simulations, and lab-grown tissue grafts.

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“…The ability to fabricate tubular MEW scaffolds using a rotating mandrel is of growing interest and has been demonstrated in various works, [ 7–22 ] with proposed tissue engineering applications including vascular, [ 9,14,17,22 ] bone, [ 10,17 ] kidney, [ 12 ] and heart valve. [ 13 ] Tubular scaffolds with aligned fiber meshes [ 16,17 ] and crosshatch (or “diamond”) patterns [ 18 ] are most often reported.…”

Section: Introductionmentioning

confidence: 99%

“…These 3D fiber networks have been explored for their highly tunable mechanical properties and subsequent influence on cell attachment, proliferation, and tissue regeneration for a range of applications. [1,8,9] The ability to fabricate tubular MEW scaffolds using a rotating mandrel is of growing interest and has been demonstrated in various works, [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] with proposed tissue engineering applications including vascular, [9,14,17,22] bone, [10,17] kidney, [12] and heart valve. [13] Tubular scaffolds with aligned fiber meshes [16,17] and crosshatch (or "diamond") patterns [18] are most often reported.…”

Section: Introductionmentioning

confidence: 99%