Slyker Leigh, Bonassar Lawrence J
Meinig of Biomedical Engineering, Cornell University, Ithaca, NY 14853, USA.
Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY 14853, USA.
Bioengineering (Basel). 2023 Sep 4;10(9):1037. doi: 10.3390/bioengineering10091037.
Current auricular cartilage replacements for pediatric microtia fail to address the need for long-term integration and neocartilage formation. While collagen hydrogels have been successful in fostering neocartilage formation, the toughness and extensibility of these materials do not match that of native tissue. This study used the N-terminal functionalization of collagen with alginate oligomers to improve toughness and extensibility through metal-ion complexation. Alginate conjugation was confirmed via FTIR spectroscopy. The retention of native collagen fibrillar structure, thermal gelation, and helical conformation in functionalized gels was confirmed via scanning electron microscopy, oscillatory shear rheology, and circular dichroism spectroscopy, respectively. Alginate-calcium complexation enabled a more than two-fold increase in modulus and work density in functionalized collagen with the addition of 50 mM CaCl, whereas unmodified collagen decreased in both modulus and work density with increasing calcium concentration. Additionally, the extensibility of alginate-functionalized collagen was increased at 25 and 50 mM CaCl. Following 2-week culture with auricular chondrocytes, alginate-functionalization had no effect on the cytocompatibility of collagen gels, with no effects on cell density, and increased glycosaminoglycan deposition. Custom MATLAB video analysis was then used to quantify fracture toughness, which was more than 5-fold higher following culture in functionalized collagen and almost three-fold higher in unmodified collagen.
目前用于小儿小耳畸形的耳廓软骨替代物无法满足长期整合和新软骨形成的需求。虽然胶原蛋白水凝胶已成功促进新软骨形成,但这些材料的韧性和伸展性与天然组织不匹配。本研究使用藻酸盐低聚物对胶原蛋白进行N端功能化,通过金属离子络合来提高韧性和伸展性。通过傅里叶变换红外光谱法确认了藻酸盐的共轭。分别通过扫描电子显微镜、振荡剪切流变学和圆二色光谱法确认了功能化凝胶中天然胶原纤维结构、热凝胶化和螺旋构象的保留。添加50 mM氯化钙后,藻酸盐 - 钙络合使功能化胶原蛋白的模量和功密度增加了两倍多,而未改性的胶原蛋白的模量和功密度则随钙浓度的增加而降低。此外,在25 mM和50 mM氯化钙条件下,藻酸盐功能化胶原蛋白的伸展性增加。在用耳廓软骨细胞培养2周后,藻酸盐功能化对胶原蛋白凝胶的细胞相容性没有影响,对细胞密度没有影响,但增加了糖胺聚糖的沉积。然后使用定制的MATLAB视频分析来量化断裂韧性,在功能化胶原蛋白中培养后,断裂韧性提高了5倍多,在未改性胶原蛋白中提高了近3倍。