Development of Composite Porous Scaffolds Based on Collagen and Biodegradable Poly(ester urethane)urea

Abstract

Our objective in this work was to develop a flexible, biodegradable scaffold for cell transplantation that would incorporate a synthetic component for strength and flexibility and type I collagen for enzymatic lability and cytocompatibility. A biodegradable poly(ester urethane)urea was synthesized from poly(caprolactone), 1,4-diisocyanatobutane, and putrescine. Using a thermally induced phase separation process, porous scaffolds were created from a mixture containing this polyurethane and 0%, 10%, 20%, or 30% type I collagen. The resulting scaffolds were found to have open, interconnected pores (from 7 to >100 um) and porosities from 58% to 86% depending on the polyurethane/collagen ratio. The scaffolds were also flexible with breaking strains of 82-443% and tensile strengths of 0.97-4.11 MPa depending on preparation conditions. Scaffold degradation was significantly increased when collagenase was introduced into an incubating buffer in a manner that was dependent on the mass fraction of collagen present in the scaffold. Mass losses could be varied from 15% to 59% over 8 weeks. When culturing umbilical artery smooth muscle cells on these scaffolds higher cell numbers were observed over a 4-week culture period in scaffolds containing collagen. In summary, a strong and flexible scaffold system has been developed that can degrade by both hydrolysis and collagenase degradation pathways, as well as support cell growth. This scaffold possesses properties that would make it attractive for future use in soft tissue applications where such mechanical and biological features would be advantageous.

Elastase-Sensitive Elastomeric Scaffolds with Variable Anisotropy for Soft Tissue Engineering

“…Pore sizes were calculated from SEM micrographs using NIH image J software using three images for each scaffold type. Scaffold porosity was determined using a liquid displacement method previously described (6,27,28) that was similar to that reported by Zhang and Ma (23) and Hsu et al (29). Ethanol was used as the displacement liquid.…”

The Microenvironment of Freeze-Injured Mouse Urinary Bladders Enables Successful Tissue Engineering

“…3,4 Before clinical applications of these cells is possible, researchers and clinicians must overcome several problems including improved survival rate for the implanted cells, differentiation into the target cell type, and structural support that enables the reconstruction of the recipient tissues. [5][6][7][8] To overcome the problems, the utilization of scaffolds, 9,10 growth factors, 11 and combinations of these materials 12,13 has been investigated. The survival, differentiation, and reorganization of the implanted cells are affected by the microenvironment within the recipient tissues [14][15][16][17] ; however, our understanding of these microenvironmental variables is currently insufficient to provide for clinically effective and reliable resources for regenerative medicine.…”

A Review of Three-Dimensional In Vitro Tissue Models for Drug Discovery and Transport Studies

“…This same group also developed a modified porous scaffold which incorporated collagen I to improve cytocompatibility and confer susceptibility to enzymatic degradation of the scaffold. 109 This porous, collagen-containing scaffold enabled high cell density while providing a strong, flexible, biodegradable support that could be degraded by both hydrolysis and collagenase pathways. 109 Cheema et al 104 performed studies of early skeletal muscle development by seeding skeletal myoblasts onto 3D collagen lattices and observing the differentiation and fusion of myoblasts to form myotubes, which is an early stage in myogenesis.…”

“…109 This porous, collagen-containing scaffold enabled high cell density while providing a strong, flexible, biodegradable support that could be degraded by both hydrolysis and collagenase pathways. 109 Cheema et al 104 performed studies of early skeletal muscle development by seeding skeletal myoblasts onto 3D collagen lattices and observing the differentiation and fusion of myoblasts to form myotubes, which is an early stage in myogenesis. Using this 3D model to evaluate the mechanical behavior of the muscle organoid in 3D culture environment, differences in force generation could be measured as the myoblasts matured and fused.…”