Bhunia Bibhas K, Mandal Biman B
Biomaterial and Tissue Engineering Laboratory, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781 039, India.
ACS Biomater Sci Eng. 2019 Feb 11;5(2):870-886. doi: 10.1021/acsbiomaterials.8b01099. Epub 2019 Jan 8.
Hydrogels have received considerable attention in the field of tissue engineering because of their unique structural and compositional resemblance to the highly hydrated human tissues. In addition, controlled fabrication processes benefit them with desirable physicochemical features for injectability in minimally invasive manner and cell survival within hydrogels. Formulation of biologically active hydrogels with desirable characteristics is one of the prerequisites for successful applications like nucleus pulposus (NP) tissue engineering to address disc degeneration. To achieve such a benchmark, in this study, two naturally derived silk fibroin proteins (, BM SF; and , AA SF) were blended together to allow self-assembly and transformation to hydrogels in absence of any cross-linker or external stimuli. A comprehensive study on sol-gel transition of fabricated hydrogels in physiological fluid microenvironment (pH, temperature, and ionic strength) was conducted using optical and fluorescence analysis. Tunable gelation time (∼8-40 min) was achieved depending on combinations. The developed hydrogels were validated by extensive physicochemical characterizations which include confirmation of secondary structure, surface morphology, swelling and degradation. Mechanical behavior of the hydrogels was further analyzed in various in vitro-physiological-like conditions with varying pH, ionic strength, diameter, storage time, and strain values to determine their suitability in native physiological environments. Rheological study, cytocompatibility using primary porcine NP cells and ex vivo biomechanics of hydrogels were explored to validate their in situ applicability in minimally invasive manner toward potential disc regeneration therapy.
水凝胶因其独特的结构和组成与高度水合的人体组织相似，在组织工程领域受到了广泛关注。此外，可控的制备工艺赋予了它们理想的物理化学特性，使其能够以微创方式注射，并有利于水凝胶内的细胞存活。制备具有理想特性的生物活性水凝胶是成功应用于如髓核（NP）组织工程以解决椎间盘退变等问题的先决条件之一。为了达到这一标准，在本研究中，将两种天然来源的丝素蛋白（BM SF和AA SF）混合在一起，使其在没有任何交联剂或外部刺激的情况下进行自组装并转变为水凝胶。使用光学和荧光分析对制备的水凝胶在生理流体微环境（pH、温度和离子强度）中的溶胶-凝胶转变进行了全面研究。根据不同组合实现了可调的凝胶化时间（约8-40分钟）。通过广泛的物理化学表征对所开发的水凝胶进行了验证，这些表征包括二级结构确认、表面形态、溶胀和降解。在不同的体外类似生理条件下，对水凝胶在不同pH、离子强度、直径、储存时间和应变值下的力学行为进行了进一步分析，以确定它们在天然生理环境中的适用性。通过流变学研究、使用原代猪NP细胞的细胞相容性以及水凝胶的离体生物力学研究，验证了它们以微创方式对潜在椎间盘再生治疗的原位适用性。
