Wilson Reid L, Connell Jennifer P, Grande-Allen K Jane
Department of Bioengineering, Rice University, 6100 Main Street, Houston, Texas 77005, United States.
Medical Scientist Training Program, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030, United States.
ACS Biomater Sci Eng. 2019 Sep 9;5(9):4522-4530. doi: 10.1021/acsbiomaterials.9b00257. Epub 2019 Aug 1.
A major barrier to the creation of engineered organs is the limited diffusion of oxygen through biological tissues. Advances in biofabrication bring us increasingly closer to complex vascular networks capable of supplying oxygen to large cellularized scaffolds. However, technologies for monitoring oxygen levels in engineered tissues do not accommodate imaging depths of more than a few dozen micrometers. Here, we report the creation of fluorescent porphyrin-hydrogel microparticles that can be used at depths of 2 mm into artificial tissues. By combining an oxygen-responsive porphyrin dye with a reference dye, the microparticles generate a ratiometric signal that is photostable, unaffected by attenuation from biological material, and responsive to physiological change in oxygen concentration. These microparticles can measure long-distance oxygen gradients within 3D, cellularized constructs and accurately report cellular oxygen consumption rates. Furthermore, they are compatible with a number of hydrogel polymerization chemistries and cell types, including primary human cells. We believe this technology will significantly advance efforts to visualize oxygen gradients in cellularized constructs and inform efforts to tissue engineer solid organs.
构建工程器官的一个主要障碍是氧气在生物组织中的扩散有限。生物制造技术的进步使我们越来越接近能够为大型细胞化支架提供氧气的复杂血管网络。然而，用于监测工程组织中氧气水平的技术无法适应超过几十微米的成像深度。在此，我们报告了荧光卟啉 - 水凝胶微粒的创建，其可用于深入人工组织2毫米的深度。通过将氧响应性卟啉染料与参比染料相结合，这些微粒产生一种比率信号，该信号具有光稳定性，不受生物材料衰减的影响，并且对氧浓度的生理变化有响应。这些微粒可以测量三维细胞化构建体中的长距离氧梯度，并准确报告细胞耗氧率。此外，它们与多种水凝胶聚合化学和细胞类型兼容，包括原代人类细胞。我们相信这项技术将显著推动在细胞化构建体中可视化氧梯度的努力，并为实体器官组织工程提供信息。
