School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea.
School of Mechanical Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea.
Acta Biomater. 2019 Oct 1;97:141-153. doi: 10.1016/j.actbio.2019.07.044. Epub 2019 Jul 26.
Multifunctional biomaterials that can provide physical, electrical, and structural cues to cells and tissues are highly desirable to mimic the important characteristics of native tissues and efficiently modulate cellular behaviors. Especially, electrically conductive biomaterials can efficiently deliver electrical signals to living systems; however, the production of conductive biomaterials presenting multiple cell interactive cues is still a great challenge. In this study, we fabricafed an electrically conductive, mechanically soft, and topographically active hydrogel by micropatterning a graphene oxide (GO)-incorporated polyacrylamide hydrogel (GO/PAAm) with femtosecond laser ablation (FLA) and subsequent chemical reduction. FLA parameters were optimized to efficiently produce distinct line patterns on GO/PAAm hydrogels to induce myoblast alignment and maturation. The line patterns distances (PD) were varied to have different topographies (20-80 μm PD). In vitro studies with C2C12 myoblasts revealed that the micopatterned hydrogels are superior to the unpatterned substrates in inducing myogenesis and myotube alignment. Reduced GO/PAAm with 50 μm PD, i.e., PD50/r(GO/PAAm), showed the best results among the various features for differentiation and myotube alignment. Electrical stimulation of myoblasts on the micropatterned conductive hydrogels further promoted the differentiation of myoblasts. In vivo implantation studies indicated good tissue compatibility of PD50/r(GO/PAAm) samples. Altogether, we successfully demonstrated that the micropatterned r(GO/PAAm) may offer multiple properties capable of positively affecting myoblast responses. This hydrogel may serve as an effective multifunctional biomaterial, which possesses the topography for cell alignment/maturation, mechanical properties of the native skeletal muscle tissue, and desirable electrical conductivity for delivering electrical signals to cells, for various biomedical applications such as muscle tissue scaffolds. STATEMENT OF SIGNIFICANCE: Micropatterned conductive hydrogels were created by polymerization of a graphene oxide-incorporated polyacrylamide hydrogel, micropatterning with femtosecond laser ablation, and chemical reduction, which can mimic important characteristics of native skeletal muscle tissues. The micropatterned conductive hydro-gels promoted myogenesis/alignment, enabled electrical stimulation of myoblasts, and displayed good tissue compatibility, which can therefore serve as a multifunctional biomaterial that is topographically active, mechanically soft, and electrically conductive for delivering multiple cell stimulating signals for potential skeletal muscle tissue engineering applications.
多功能生物材料能够为细胞和组织提供物理、电气和结构线索，高度模拟天然组织的重要特征，并有效调节细胞行为。特别是，导电生物材料可以有效地将电信号传递给活体系统；然而，生产具有多种细胞相互作用线索的导电生物材料仍然是一个巨大的挑战。在这项研究中，我们通过飞秒激光烧蚀（FLA）和随后的化学还原，制造了一种具有导电性、柔软性和形貌活性的聚酰胺水凝胶，该水凝胶中掺入了氧化石墨烯（GO）。优化了 FLA 参数，以有效地在 GO/PAAm 水凝胶上产生不同的线图案，以诱导成肌细胞的排列和成熟。改变线图案距离（PD）以获得不同的形貌（20-80μm PD）。与 C2C12 成肌细胞的体外研究表明，微图案化水凝胶在诱导成肌发生和肌管排列方面优于非图案化基底。具有 50μm PD 的还原 GO/PAAm，即 PD50/r（GO/PAAm），在各种特征中表现出最佳的分化和肌管排列效果。对微图案化导电水凝胶上的成肌细胞进行电刺激进一步促进了成肌细胞的分化。体内植入研究表明 PD50/r（GO/PAAm）样品具有良好的组织相容性。总的来说，我们成功地证明了微图案化 r（GO/PAAm）可能提供多种能够积极影响成肌细胞反应的特性。这种水凝胶可用作有效的多功能生物材料，具有细胞排列/成熟的形貌、天然骨骼肌组织的机械性能以及为细胞传递电信号的理想导电性，可用于各种生物医学应用，如肌肉组织支架。
