Department of Chemical and Materials Engineering, University of Kentucky, Lexington, Kentucky, USA.
Gill Heart and Vascular Institute and Division of Cardiovascular Medicine, University of Kentucky, Lexington, Kentucky, USA.
J Biomed Mater Res A. 2021 Mar;109(3):326-335. doi: 10.1002/jbm.a.37025. Epub 2020 Jun 20.
Gelatin coatings are effective in increasing the retention of MSCs injected into the heart and minimizing the damage from acute myocardial infarction (AMI), but early studies suffered from low fractions of the MSCs coated with gelatin. Biotinylation of the MSC surface is a critical first step in the gelatin coating process, and in this study, we evaluated the use of biotinylated cholesterol "lipid insertion" anchors as a substitute for the covalent NHS-biotin anchors to the cell surface. Streptavidin-eosin molecules, where eosin is our photoinitiator, can then be bound to the cell surface through biotin-streptavidin affinity. The use of cholesterol anchors increased streptavidin density on the surface of MSCs further driving polymerization and allowing for an increased fraction of MSCs coated with gelatin (83%) when compared to NHS-biotin (52%). Additionally, the cholesterol anchors increased the uniformity of the coating on the MSC surface and supported greater numbers of coated MSCs even when the streptavidin density was slightly lower than that of an NHS-biotin anchoring strategy. Critically, this improvement in gelatin coating efficiency did not impact cytokine secretion and other critical MSC functions. Proper selection of the cholesterol anchor and the biotinylation conditions supports cellular function and densities of streptavidin on the MSC surface of up to ~10 streptavidin molecules/μm . In all, these cholesterol anchors offer an effective path towards the formation of conformal coatings on the majority of MSCs to improve the retention of MSCs in the heart following AMI.
明胶涂层可有效提高注射到心脏的间充质干细胞的保留率，最大限度地减少急性心肌梗死（AMI）造成的损伤，但早期的研究中，涂有明胶的间充质干细胞比例较低。MSC 表面的生物素化是明胶涂层过程中的关键第一步，在这项研究中，我们评估了使用生物素化胆固醇“脂质插入”锚作为替代物与细胞表面的 NHS-生物素锚连接。然后，链霉亲和素-曙红分子（曙红是我们的光引发剂）可以通过生物素-链霉亲和素亲和力结合到细胞表面。胆固醇锚的使用进一步增加了 MSCs 表面上链霉亲和素的密度，从而进一步推动聚合反应，使涂有明胶的 MSCs 比例（83%）比 NHS-生物素（52%）更高。此外，胆固醇锚增加了 MSC 表面涂层的均匀性，即使链霉亲和素密度略低于 NHS-生物素锚定策略，也支持更多涂有明胶的 MSC。至关重要的是，这种明胶涂层效率的提高并不影响细胞因子分泌和其他关键 MSC 功能。正确选择胆固醇锚和生物素化条件可支持细胞功能，并使 MSC 表面上的链霉亲和素密度高达约 10 个链霉亲和素分子/μm 。总之，这些胆固醇锚为在大多数 MSC 上形成共形涂层提供了有效途径，以提高 AMI 后 MSC 在心脏中的保留率。
