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Fractures of the orbital floor are common in traffic accidents and assaults, and inadequate treatment can result in serious complications. Accurate anatomical reconstruction of the orbit using implants is the preferred treatment. Implants require degradability, adequate mechanical properties to support the orbital contents, and osteoinductivity or osteoconductivity so that the implant is replaced by de novo bone over time. Here, we report on a semi-automatic process for the generation of virtual models of patient-specific implants for orbital floor reconstruction. These models were generated using clinical computed tomography images of five clinical cases of orbital fracture. To fabricate accurately shaped implants based on the models, we utilized stereolithography, a high-resolution additive manufacturing technique. We prepared resins from bioresorbable, photo-curable functionalized poly(trimethylene carbonate) oligomers and osteoinductive nano-hydroxyapatite to manufacture composite implants. Incorporation of 40 wt.% nano-hydroxyapatite into photo-crosslinked poly(trimethylene carbonate) leads to an increase of the E modulus, ultimate strength and toughness from 2.8 to 60 MPa, 2.4 to 7.1 N/mm2 and 330 to 1671 N/mm2, respectively. Additionally, water uptake increased from 0.8% to 7.3%, and water contact angle decreased from 80°to 68°. Patient-specific, homogeneous, and mechanically stable implants can readily be prepared using these composite resins.

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Designing calcium phosphate‐loaded polymeric porous scaffolds with controlled architecture using stereolithography (SLA) has great potential in the field of bone tissue engineering. However, the use of poly(ester)s with suboptimal degradation property has mainly been reported. In the present work, we introduced a poly(trimethylene carbonate) (PTMC) and nano‐hydroxyapatite (HA) resin suitable for SLA manufacturing and created cytocompatible 3D porous structure. First, the resin formulation and HA content were optimized for photo‐crosslink‐based SLA fabrication process. Subsequently, we evaluated the influence of the resin composition on physico‐chemical characteristics of fabricated films and scaffolds. Then, the influence of the biomaterial composition on human bone marrow mesenchymal stem cell viability, adhesion and proliferation was assessed. Films and macroporous scaffolds were successfully produced by photo‐crosslinking with up to 40 wt% of HA (relative to PTMC). We demonstrated that addition of HA in PTMC matrices induced a direct effect on the surface properties, in terms of wettability and topography. Additionally, mechanical tests revealed a correlation between the amounts of HA loaded in PTMC and the stiffness of the SLA‐fabricated scaffolds. Importantly, the different photo‐crosslinked biomaterials exhibited in vitro cytocompatibility, similar to tissue culture polystyrene. Those data suggest the possibility to fabricate highly tunable HA‐loaded PTMC 3D porous structures for bone tissue engineering application. Copyright © 2016 John Wiley & Sons, Ltd.

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This work combines computational fluid dynamics simulations and stereolithographic printing to fabricate 3D-parallelized microfluidic droplet generators with equal flow profiles.

A thermoresponsive copolymer incorporating a quaternary amine group, poly(N-isopropylacrylamide-co-3-acrylamidopropyl trimethylammonium chloride (APTAC)-co-tert-butylacrylamide), was conjugated to the surface of silica beads through surface-initiated atom transfer radical polymerization. Prepared copolymer- and copolymer brush-modified beads were characterized by CHN elemental analysis, X-ray photoelectron spectroscopy, gel permeation chromatography, and observation of phase transition profiles. Phase transition profiles of the prepared copolymer indicated that 5 mol % APTAC is suitable for enabling thermally modulated property changes in the copolymer. Chromatographic elution behaviors of adenosine nucleotides and proteins were observed using prepared beads as chromatography matrices. Higher retention time of adenosine nucleotides and strong protein adsorption behavior were observed compared with those on beads with tertiary amine groups, because of the strong basic properties. Therefore, copolymer brush modified beads will be useful as thermoresponsive ion-exchange chromatographic matrices.