High Speed Sintering of Polyamide 12: From Powder to Part Properties.

High Speed Sintering (HSS) is an additive manufacturing process with great potential to produce complex, high-quality polymer parts on an industrial scale. However, little information is currently available on the characteristics of the powder materials used and the part properties that can be achieved. This is also the case for the standard material polyamide 12 (PA 12) and the first commercially available HSS machine, the VX200 HSS.

Tropoelastin incorporation into a dermal regeneration template promotes wound angiogenesis.

Severe burn injury results in substantial skin loss and cannot be treated by autografts. The Integra Dermal Regeneration Template (IDRT) is the leading synthetic skin substitute because it allows for wound bed regeneration and wound healing. However, all substitutes suffer from slow blood vessel ingrowth and would benefit considerably from enhanced vascularization to nurture tissue repair.

The effect of collagen nerve conduits filled with collagen-glycosaminoglycan matrix on peripheral motor nerve regeneration in a rat model.

Background: Bioabsorbable unfilled synthetic nerve conduits have been used in the reconstruction of small segmental nerve defects with variable results, especially in motor nerves. We hypothesized that providing a synthetic mimic of the Schwann cell basal lamina in the form of a collagen-glycosaminoglycan (GAG) matrix would improve the bridging of the nerve gap and functional motor recovery.

Methods: A unilateral 10-mm sciatic nerve defect was created in eighty-eight male Lewis rats.

Engineered cellular response to scaffold architecture in a rabbit trephine defect.

Tight control of pore architecture in porous scaffolds for bone repair is critical for a fully elucidated tissue response. Solid freeform fabrication (SFF) enables construction of scaffolds with tightly controlled pore architecture. Four types of porous scaffolds were constructed using SFF and evaluated in an 8-mm rabbit trephine defect at 8 and 16 weeks (n = 6): a lactide/glycolide (50:50) copolymer scaffold with 20% w/w tri-calcium phosphate and random porous architecture (Group 1); another identical design made from poly(desaminotyrosyl-tyrosine ethyl ester carbonate) [poly(DTE carbonate)], a tyrosine-derived pseudo-polyamino acid (Group 2); and two poly(DTE carbonate) scaffolds containing 500 microm pores separated by 500-microm thick walls, one type with solid walls (Group 3), and one type with microporous walls (Group 4).

Polymer of proline analogue with sustained antifibrotic activity in lung fibrosis.

Inhibitors of collagen such as cis-4-hydroxy-L-proline (cHyp) may ameliorate bleomycin (bleo)-induced pulmonary fibrosis. An alternating polymer of poly(ethylene glycol) (PEG)-lysine (PEG-Lys) with cHyp attached as a pendant side chain was prepared for intratracheal delivery with bioinactive trans-Hyp (tHyp) polymer as control. To test whether the cHyp polymer has prolonged lung retention and sustained antifibrotic activity, we first instilled 3H- and 14C-labeled cHyp polymer in normal rats.