Gupta Divya, Santoso Jeffrey W, McCain Megan L
Laboratory for Living Systems Engineering, Department of Biomedical Engineering, Viterbi School of Engineering, University of Southern California, 1042 Downey Way, DRB 140, Los Angeles, CA 90089, USA.
Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine, University of Southern California, 1975 Zonal Ave, Los Angeles, CA 90033, USA.
Bioengineering (Basel). 2021 Jan 6;8(1):6. doi: 10.3390/bioengineering8010006.
Engineered in vitro models of skeletal muscle are essential for efficiently screening drug safety and efficacy. However, conventional culture substrates poorly replicate physical features of native muscle and do not support long-term culture, which limits tissue maturity. Micromolded gelatin hydrogels cross-linked with microbial transglutaminase (gelatin-MTG hydrogels) have previously been shown to induce C21C2 myotube alignment and improve culture longevity. However, several properties of gelatin-MTG hydrogels have not been systematically characterized, such as changes in elastic modulus during incubation in culture-like conditions and their ability to support sarcomere maturation. In this study, various gelatin-MTG hydrogels were fabricated and incubated in ambient or culture-like conditions. Elastic modulus, mass, and transmittance were measured over a one- or two-week period. Compared to hydrogels in phosphate buffered saline (PBS) or ambient air, hydrogels in Dulbecco's Modified Eagle Medium (DMEM) and 5% CO demonstrated the most stable elastic modulus. A subset of gelatin-MTG hydrogels was micromolded and seeded with C2C12 or primary chick myoblasts, which aligned and fused into multinucleated myotubes with relatively mature sarcomeres. These data are important for fabricating gelatin-MTG hydrogels with predictable and stable mechanical properties and highlight their advantages as culture substrates for engineering relatively mature and stable muscle tissues.
骨骼肌的工程化体外模型对于高效筛选药物安全性和有效性至关重要。然而，传统的培养底物很难复制天然肌肉的物理特征，也不支持长期培养，这限制了组织的成熟度。先前已证明，与微生物转谷氨酰胺酶交联的微模塑明胶水凝胶（明胶-MTG水凝胶）可诱导C2C12肌管排列并提高培养寿命。然而，明胶-MTG水凝胶的一些特性尚未得到系统表征，例如在类似培养条件下孵育期间弹性模量的变化及其支持肌节成熟的能力。在本研究中，制备了各种明胶-MTG水凝胶，并在环境条件或类似培养条件下孵育。在一到两周的时间内测量弹性模量、质量和透光率。与磷酸盐缓冲盐水（PBS）或环境空气中的水凝胶相比，杜氏改良 Eagle 培养基（DMEM）和5% CO2中的水凝胶表现出最稳定的弹性模量。将一部分明胶-MTG水凝胶进行微模塑，并接种C2C12或原代鸡成肌细胞，这些细胞排列并融合成具有相对成熟肌节的多核肌管。这些数据对于制备具有可预测和稳定机械性能的明胶-MTG水凝胶很重要，并突出了它们作为工程化相对成熟和稳定肌肉组织的培养底物的优势。
