Laser 3D Printing with Sub‐Microscale Resolution of Porous Elastomeric Scaffolds for Supporting Human Bone Stem Cells

Abstract

A reproducible method is needed to fabricate 3D scaffold constructs that results in periodic and uniform structures with precise control at sub-micrometer and micrometer length scales. In this study, fabrication of scaffolds by two-photon polymerization (2PP) of a biodegradable urethane and acrylate-based photoelastomer is demonstrated. This material supports 2PP processing with sub-micrometer spatial resolution. The high photoreactivity of the biophotoelastomer permits 2PP processing at a scanning speed of 1000 mm s(-1), facilitating rapid fabrication of relatively large structures (>5 mm(3)). These structures are custom printed for in vitro assay screening in 96-well plates and are sufficiently flexible to enable facile handling and transplantation. These results indicate that stable scaffolds with porosities of greater than 60% can be produced using 2PP. Human bone marrow stromal cells grown on 3D scaffolds exhibit increased growth and proliferation compared to smooth 2D scaffold controls. 3D scaffolds adsorb larger amounts of protein than smooth 2D scaffolds due to their larger surface area; the scaffolds also allow cells to attach in multiple planes and to completely infiltrate the porous scaffolds. The flexible photoelastomer material is biocompatible in vitro and is associated with facile handling, making it a viable candidate for further study of complex 3D-printed scaffolds.

Experimental and numerical study on laser keyhole welding of 42CrMo under air and argon atmosphere

“…For friction welding, the low efficiency and welding defects are concerning. Alternatively, highpower-density laser has attracted enormous research interest and found its wide application in a broad branch of manufacturing areas including selective laser sintering and three-dimensional printing [1][2][3][4][5][6], surface nanostructuring [7][8][9][10][11][12], multimaterial joining and integration [13][14][15][16][17], material removal [18,19], and mechanical/optical property enhancements [20][21][22][23]. Characteristics, such as contact-free processing, good flexibility and tunablity, high efficiency, and throughput, make laser a feasible route for welding of 42CrMo [24,25].…”

An academic, clinical and industrial update on electrospun, additive manufactured and imprinted medical devices

“…Dunn and Brown (1986) First in vitro study to demonstrate cell behaviour in response to imprinted patterns by electron beam lithography and photolithography [136] Chou et al (1995) Introduction of nano-imprint lithography for the development of nano-scale features (sub-25 nm) [137] Charest Additive manufacturing Biodegradable synthetic polymers [64][65][66][67] Ideally, through a hydrogel [81,82] The most precise 3D fabrication technology; precision down to 100 nm [3,4] Permanently differentiated cell phenotype maintenance [71,77] Primarily bone and cartilage [69,70,72] Imprint lithography Non-degradable synthetic polymers [91,92] Limited [92,110,111] The most precise 2D fabrication technology; precision down to 5 nm [5,96,97] Permanently differentiated cell phenotype maintenance [91,100]; control of stem cell lineage [140] differentiation of mouse embryonic stem cells into neural lineages and promote and guide neurite outgrowth [11], promote the neuronal differentiation of human embryonic stem cells [12,13] and regulate proliferation, differentiation and neurite outgrowth of neural stem cells in culture [14,15]. It is worth pointing out that a recent study argues that fibre diameter seems to be even more important than fibre orientation in differentiated mesenchymal stem cells towards tenogenic lineage [16].…”

“…A recent study demonstrated the fabrication of 3D scaffolds with periodic and uniform porosity at nano-to micro-length scales by two-photon polymerisation of a biodegradable urethane and acrylate-based photo-elastomer, which increased growth and proliferation of human bone marrow stromal stem cells in vitro [71]. Further, scaffolds produced via AM have successfully recreated the macro-pore structure of tissues, facilitating cell colonisation and tissue ingrowth within the inner space of 3D scaffolds in vivo in cartilage [72], bone [73], oesophageal [74], cardiac [75] and vascular [76] indications.…”

Capillary convection in pulsed – butt welding of miscible dissimilar couple

“…High power density lasers have attracted intense research interest in various areas of advanced manufacturing [11][12][13][14][15][16][17][18][19][20][21][22] due to their high efficient, precise, and flexible material-processing features. The transport phenomena during laser-matter interaction is the key for their implementations.…”