Department of Mining and Materials Engineering, McGill University, Canada.
Biofabrication. 2016 Mar 22;8(1):015018. doi: 10.1088/1758-5090/8/1/015018.
A gel aspiration-ejection (GAE) system has been developed for the advanced production and delivery of injectable dense collagen (I-DC) gels of unique collagen fibrillar densities (CFDs). Through the creation of negative pressure, GAE aspirates prefabricated highly hydrated collagen gels into a needle, simultaneously inducing compaction and meso-scale anisotropy (i.e., fibrillar alignment) on the gels, and by subsequent reversal of the pressure, I-DC gels can be controllably ejected. The system generates I-DC gels with CFDs ranging from 5 to 32 wt%, controlling the initial scaffold microstructure, anisotropy, hydraulic permeability, and mechanical properties. These features could potentially enable the minimally invasive delivery of more stable hydrogels. The viability, metabolic activity, and differentiation of seeded mesenchymal stem cells (MSCs) was investigated in the I-DC gels of distinct CFDs and extents of anisotropy produced through two different gauge needles. MSC osteoblastic differentiation was found to be relatively accelerated in I-DC gels that combined physiologically relevant CFDs and increased fibrillar alignment. The ability to not only support homogenous cell seeding, but also to direct and accelerate their differentiation through tissue-equivalent anisotropy, creates numerous opportunities in regenerative medicine.
一种凝胶抽吸-喷射（GAE）系统已被开发出来，用于先进的生产和输送具有独特胶原纤维密度（CFD）的可注射致密胶原（I-DC）凝胶。通过创建负压，GAE 将预制的高度水合胶原凝胶吸入针中，同时对凝胶进行压实和中尺度各向异性（即纤维排列），随后反转压力，可可控地喷射 I-DC 凝胶。该系统可生成 CFD 范围为 5 至 32wt%的 I-DC 凝胶，控制初始支架微结构、各向异性、水力渗透性和机械性能。这些特性可能能够实现更稳定水凝胶的微创递送。通过两种不同规格的针，在不同 CFD 和各向异性程度的 I-DC 凝胶中研究了种子间充质干细胞（MSCs）的活力、代谢活性和分化。发现 MSC 成骨分化在结合了生理相关 CFD 和增加纤维排列的 I-DC 凝胶中相对加速。不仅能够支持均匀的细胞接种，而且能够通过组织等效各向异性来指导和加速其分化，这在再生医学中创造了众多机会。
