Roseen Madeleine A, Lee Romi, Post Allison D, Wancura Megan, Connell Jennifer P, Cosgriff-Hernandez Elizabeth, Grande-Allen K Jane
Department of Bioengineering, Rice University, Houston 77005, Texas, United States.
Department of Biomedical Engineering, University of Texas at Austin, Austin 78712, Texas, United States.
ACS Appl Bio Mater. 2020 Dec 21;3(12):8352-8360. doi: 10.1021/acsabm.0c00550. Epub 2020 Nov 10.
Bioprosthetic valves (BPVs) have a limited lifespan in the body necessitating repeated surgeries to replace the failed implant. Early failure of these implants has been linked to various surface properties of the valve. Surface properties of BPVs are significantly different from physiological valves because of the fixation process used when processing the xenograft tissue. To improve the longevity of BPVs, efforts need to be taken to improve the surface properties and shield the implant from the bodily interactions that degrade it. Toward this goal, we evaluated the use of hydrogel coatings to attach to the BPV tissue and impart surface properties that are close to physiological. Hydrogels are well characterized for their biocompatibility and highly tunable surface characteristics. Using a previously published coating method, we deposited hydrogel coatings of poly(ethylene glycol)diacrylate (PEGDA) and poly(ethylene glycol)diacrylamide (PEGDAA) atop BPV samples. Coated samples were evaluated against the physiological tissue and uncoated glutaraldehyde-fixed tissue for deposition of hydrogel, surface adherence, mechanical properties, and fixation properties. Results showed both PEGDA- and PEGDAA-deposited coatings were nearly continuous across the valve leaflet surface. Further, the PEGDA- and PEGDAA-coated samples showed restoration of physiological levels of protein adhesion and mechanical stiffness. Interestingly, the coating process rather than the coating itself altered the material behavior yet did not alter the cross-linking from fixation. These results show that the PEG-based coatings for BPVs can successfully alter surface properties of BPVs and help promote physiological characteristics without interfering with the necessary fixation.
生物人工瓣膜（BPV）在体内的使用寿命有限，因此需要反复进行手术以更换失效的植入物。这些植入物的早期失效与瓣膜的各种表面特性有关。由于在处理异种移植组织时使用的固定过程，BPV的表面特性与生理瓣膜有显著差异。为了提高BPV的使用寿命，需要努力改善其表面特性，并保护植入物免受导致其降解的身体相互作用的影响。为了实现这一目标，我们评估了使用水凝胶涂层附着在BPV组织上，并赋予其接近生理状态的表面特性。水凝胶因其生物相容性和高度可调节的表面特性而得到充分表征。使用先前发表的涂层方法，我们在BPV样本上沉积了聚（乙二醇）二丙烯酸酯（PEGDA）和聚（乙二醇）二丙烯酰胺（PEGDAA）的水凝胶涂层。对涂覆的样本与生理组织和未涂覆的戊二醛固定组织进行了水凝胶沉积、表面附着力、机械性能和固定性能的评估。结果表明，PEGDA和PEGDAA沉积的涂层在瓣膜小叶表面几乎是连续的。此外，PEGDA和PEGDAA涂覆的样本显示蛋白质粘附和机械刚度恢复到生理水平。有趣的是，涂层过程而非涂层本身改变了材料行为，但没有改变固定过程中的交联。这些结果表明，用于BPV的基于PEG的涂层可以成功改变BPV的表面特性，并有助于促进生理特性，而不会干扰必要的固定过程。
