Tissue Engineering Research Group, Department of Anatomy and Regenerative Medicine, RCSI University of Medicine and Health Sciences, Dublin, Ireland.
Advanced Materials and Bioengineering Research Centre (AMBER), RCSI and TCD, Dublin, Ireland.
Biofabrication. 2023 Oct 27;16(1). doi: 10.1088/1758-5090/ad047a.
Current treatments for repairing articular cartilage defects are limited. However, pro-chondrogenic hydrogels formulated using articular cartilage matrix components (such as hyaluronic acid (HA) and collagen type II (Col II)), offer a potential solution if they could be injected into the defect via minimally invasive arthroscopic procedures, or used as bioinks to 3D print patient-specific customised regenerative scaffolds-potentially combined with cells. However, HA and Col II are difficult to incorporate into injectable/3D printable hydrogels due to poor physicochemical properties. This study aimed to overcome this by developing an articular cartilage matrix-inspired pro-chondrogenic hydrogel with improved physicochemical properties for both injectable and 3D printing (3DP) applications. To achieve this, HA was methacrylated to improve mechanical properties and mixed in a 1:1 ratio with Col I, a Col I/Col II blend or Col II. Col I possesses superior mechanical properties to Col II and so was hypothesised to enhance hydrogel mechanical properties. Rheological analysis showed that the pre-gels had viscoelastic and shear thinning properties. Subsequent physicochemical analysis of the crosslinked hydrogels showed that Col II inclusion resulted in a more swollen and softer polymer network, without affecting degradation time. While all hydrogels exhibited exemplary injectability, only the Col I-containing hydrogels had sufficient mechanical stability for 3DP applications. To facilitate 3DP of multi-layered scaffolds using methacrylated HA (MeHA)-Col I and MeHA-Col I/Col II, additional mechanical support in the form of a gelatin slurry support bath freeform reversible embedding of suspended hydrogels was utilised. Biological analysis revealed that Col II inclusion enhanced hydrogel-embedded MSC chondrogenesis, thus MeHA-Col II was selected as the optimal injectable hydrogel, and MeHA-Col I/Col II as the preferred bioink. In summary, this study demonstrates how tailoring biomaterial composition and physicochemical properties enables development of pro-chondrogenic hydrogels with potential for minimally invasive delivery to injured articular joints or 3DP of customised regenerative implants for cartilage repair.
目前修复关节软骨缺损的方法有限。然而，如果能通过微创关节镜手术将具有软骨形成特性的水凝胶制剂（如透明质酸（HA）和 II 型胶原（Col II））注射到缺损部位，或者将其用作生物墨水来 3D 打印患者特异性定制的再生支架——可能与细胞结合使用，那么由关节软骨基质成分（如透明质酸（HA）和 II 型胶原（Col II））组成的具有软骨形成特性的水凝胶制剂就提供了一种潜在的解决方案。然而，由于理化性质较差，HA 和 Col II 很难被纳入可注射/3D 打印水凝胶中。本研究旨在通过开发一种具有改善的理化性质的关节软骨基质启发的具有软骨形成特性的水凝胶来克服这一难题，该水凝胶可用于可注射和 3D 打印（3DP）应用。为了实现这一目标，对 HA 进行了甲基丙烯酰化以改善机械性能，并将其以 1:1 的比例与 Col I、Col I/Col II 混合物或 Col II 混合。Col I 的机械性能优于 Col II，因此假设它可以增强水凝胶的机械性能。流变分析表明，预凝胶具有粘弹性和剪切稀化特性。随后对交联水凝胶的理化分析表明，Col II 的加入导致聚合物网络更加溶胀和柔软，而不影响降解时间。虽然所有水凝胶都表现出良好的可注射性，但只有含有 Col I 的水凝胶具有用于 3DP 应用的足够机械稳定性。为了促进甲基丙烯酰化 HA（MeHA）-Col I 和 MeHA-Col I/Col II 的多层支架的 3DP，以明胶浆料支撑浴的形式提供了额外的机械支撑，以自由形成悬浮水凝胶的可逆嵌入。生物学分析表明，Col II 的加入增强了水凝胶包埋的 MSC 软骨形成，因此选择 MeHA-Col II 作为最佳可注射水凝胶，选择 MeHA-Col I/Col II 作为首选生物墨水。总之，本研究表明，通过调整生物材料的组成和理化性质，可以开发出具有潜在的微创给药能力的软骨形成水凝胶，用于受伤的关节软骨，或用于 3D 打印定制的再生植入物以修复软骨。
