Shape-fitting collagen-PLA composite promotes osteogenic differentiation of porcine adipose stem cells. (July 2019)

• Record Type: Journal Article
• Authors: Dewey, Marley J.; Johnson, Eileen M.; Weisgerber, Daniel W.; Wheeler, Matthew B.; Harley, Brendan A.C.
• Is Part Of: Journal of the mechanical behavior of biomedical materials. Volume 95(2019)
• Page Start: 21
• Page End: 33
• Publication Date: 2019-07
• Subjects: PLA poly(lactic acid) -- CMF cranio-maxillofacial -- PCL poly(caprolactone) -- pASC porcine adipose derived stem cell; Collagen -- Poly lactic acid -- Stem cell -- Osteogenesis -- Conformal fitting; Biomedical materials -- Periodicals; Biomedical materials -- Mechanical properties -- Periodicals; Biomedical materials; Biomedical materials -- Mechanical properties; Periodicals; Electronic journals; 610.28
• DOI: 10.1016/j.jmbbm.2019.03.017
• Languages: English
• ISSNs: 1751-6161

Abstract

Abstract: Craniomaxillofacial bone defects can occur as a result of congenital, post-oncologic, and high-energy impact conditions. The scale and irregularity of such defects motivate new biomaterials to promote regeneration of the damaged bone. We have recently described a mineralized collagen scaffold capable of instructing stem cell osteogenic differentiation and new bone infill in the absence of traditional osteogenic supplements. Herein, we report the integration of a millimeter-scale reinforcing poly (lactic acid) frame fabricated via 3D-printing into the mineralized collagen scaffold with micron-scale porosity to form a multi-scale mineralized collagen-PLA composite. We describe modifications to the PLA frame design to increase the compressive strength (Young's Modulus, ultimate stress and strain) of the composite. A critical challenge beyond increasing the compressive strength of the collagen scaffold is addressing challenges inherent with the irregularity of clinical defects. As a result, we examined the potential for modifying the frame architecture to render the composite with increased compressive strength in one axis or radial compressibility and shape-fitting capacity in an orthogonal axis. A library of mineralized collagen-PLA composites was mechanically characterized via compression testing and push-out test to describe mechanical performance and shape-fitting capacity. We also report in vitro comparison of the bioactivity of porcine adipose derived stem cells in the mineralized collagen-PLA composite versus the mineralized collagen scaffold via metabolic activity, gene expression, and functional matrix synthesis. The results suggest that incorporation of the PLA reinforcing frame does not negatively influence the osteoinductive nature of the mineralized collagen scaffold. Together, these findings suggest a strategy to address often competing bioactivity, mechanical strength, and shape-fitting design requirements for biomaterials for craniomaxillofacial bone regeneration. Graphical abstract: fx1 Highlights: Incorporating a poly(lactic acid) fiber cage into a mineralized collagen scaffold. Tuning the modulus of the PLA-collagen composite via PLA fiber architecture. Radially-compressible PLA fiber geometry promotes conformal fitting capacity. PLA cage does not reduce stem cell viability and osteogenesis in the composite.