Tunable Cross-Linking and Adhesion of Gelatin Hydrogels via Bioorthogonal Click Chemistry
Tunable Cross-Linking and Adhesion of Gelatin Hydrogels via Bioorthogonal Click Chemistry
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DOI：
10.1021/acsbiomaterials.1c00136
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发表时间：
2021-06-04
影响因子：
5.8
通讯作者：
Celiz, Adam D.
中科院分区：
文献类型：
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作者：
Negrini, Nicola Contessi;Volponi, Ana Angelova;Celiz, Adam D.
具有可调物理力学性能的工程细胞相容性水凝胶作为仿生三维细胞外基质（ECM）是指导细胞反应和靶组织再生或体外模型发展的基础。鉴于其ECM仿生特性，明胶代表了最佳选择；然而，需要明胶交联以确保生理温度下的结构稳定性（即t> Tsol-gel（明胶））。在这里，我们使用先前开发的四嗪(Tz)-和降冰片烯（Nb）改性明胶衍生物之间的交联反应来制备明胶水凝胶，并通过改变它们的改性程度（DOM）和Tz/Nb比(R)来证明它们的性质可能的调整。明胶衍生物的DOM百分比调整在5%到15%之间。与低DOM（60-70分钟）制备的水凝胶相比，高DOM制备的水凝胶交联速度更快（即10-20分钟）。较高的DOM和等摩尔Tz/Nb比R使水凝胶在37℃PBS中浸泡后的重量变化较小。改变DOM和R 1个数量级可以调节水凝胶的力学性能，实现弹性模量E值从0.5（低DOM和非等摩尔Tz/Nb比）到5 kPa（高DOM和等摩尔Tz/Nb比）。将人牙髓干细胞包埋于水凝胶中，成功地在水凝胶中进行了三维培养（活细胞率bb0 85%）。在力学性能较低（E < 1 kPa）的水凝胶中培养的细胞代谢活性增加，细胞形态更细长。用过量的Tz或Nb制备的水凝胶在体外培养过程中成功粘附并保持接触，突出了这些水凝胶作为区隔共培养系统的潜在用途。通过控制其生物正交交联成功调节明胶水凝胶的性质，在组织工程和体外建模应用中具有广阔的前景。
Engineering cytocompatible hydrogels with tunable physico-mechanical properties as a biomimetic three-dimensional extracellular matrix (ECM) is fundamental to guide cell response and target tissue regeneration or development of in vitro models. Gelatin represents an optimal choice given its ECM biomimetic properties; however, gelatin cross-linking is required to ensure structural stability at physiological temperature (i.e., T > Tsol-gel (gelatin)). Here, we use a previously developed cross-linking reaction between tetrazine (Tz)- and norbornene (Nb) modified gelatin derivatives to prepare gelatin hydrogels and we demonstrate the possible tuning of their properties by varying their degree of modification (DOM) and the Tz/Nb ratio (R). The percentage DOM of the gelatin derivatives was tuned between 5 and 15%. Hydrogels prepared with higher DOM cross-linked faster (i.e., 10-20 min) compared to hydrogels prepared with lower DOM (i.e., 60-70 min). A higher DOM and equimolar Tz/Nb ratio R resulted in hydrogels with lower weight variation after immersion in PBS at 37 degrees C. The mechanical properties of the hydrogels were tuned by varying DOM and R by 1 order of magnitude, achieving elastic modulus E values ranging from 0.5 (low DOM and nonequimolar Tz/Nb ratio) to 5 kPa (high DOM and equimolar Tz/Nb ratio). Human dental pulp stem cells were embedded in the hydrogels and successfully 3D cultured in the hydrogels (percentage viable cells >85%). An increase in metabolic activity and a more elongated cell morphology was detected for cells cultured in hydrogels with lower mechanical properties (E < 1 kPa). Hydrogels prepared with an excess of Tz or Nb were successfully adhered and remained in contact during in vitro cultures, highlighting the potential use of these hydrogels as compartmentalized coculture systems. The successful tuning of the gelatin hydrogel properties here developed by controlling their bioorthogonal cross-linking is promising for tissue engineering and in vitro modeling applications.