Continuous gradient scaffolds for rapid screening of cell-material interactions and interfacial tissue regeneration.

In tissue engineering, the physical and chemical properties of the scaffold mediates cell behavior including regeneration. Thus, a strategy that permits rapid screening of cell-scaffold interactions is critical. Herein, we have prepared eight “hybrid” hydrogel scaffolds in the form of continuous gradients such that a single scaffold contains spatially varied properties. These scaffolds are based on combining an inorganic macromer [methacrylated star polydimethylsiloxane, PDMSstar-MA] and organic macromer [poly(ethylene glycol)diacrylate, PEG-DA] as well both aqueous and organic fabrication solvents. Having previously demonstrated its bioactivity and osteoinductivity, PDMSstar-MA is a particularly powerful component to incorporate into instructive gradient scaffolds based on PEG-DA. The following parameters were varied to produce the different gradients or gradual transitions in: (1) the wt% ratio of PDMSstar-MA to PEG-DA macromers, (2) the total wt% macromer concentration, (3) the number average molecular weight (Mn) of PEG-DA and (4) the Mn of PDMSstar-MA. Upon dividing each scaffold into four “zones” perpendicular to the gradient, we were able to demonstrate the spatial variation in morphology, bioactivity, swelling and modulus. Among these gradient scaffolds are those in which swelling and modulus are conveniently decoupled. In addition to rapid screening of cell-material interactions, these scaffolds are well-suited for regeneration of interfacial tissues (e.g. osteochondral tissues) that transition from one tissue type to another.

在组织工程中，支架的物理和化学性质介导包括再生在内的细胞行为。因此，一种能够快速筛选细胞 - 支架相互作用的策略至关重要。在此，我们制备了八种呈连续梯度形式的“混合”水凝胶支架，使得单个支架包含空间上变化的特性。这些支架是基于将一种无机大分子单体[甲基丙烯酸酯化的星型聚二甲基硅氧烷，PDMSstar - MA]和有机大分子单体[聚(乙二醇)二丙烯酸酯，PEG - DA]以及水性和有机制备溶剂相结合。由于先前已证明其生物活性和骨诱导性，PDMSstar - MA是一种特别强大的成分，可用于构建基于PEG - DA的具有指导意义的梯度支架。通过改变以下参数来产生不同的梯度或渐变：(1) PDMSstar - MA与PEG - DA大分子单体的重量百分比比率，(2)大分子单体的总重量百分比浓度，(3) PEG - DA的数均分子量(Mn)以及(4) PDMSstar - MA的Mn。将每个支架垂直于梯度划分为四个“区域”后，我们能够证明其在形态、生物活性、溶胀和模量方面的空间变化。在这些梯度支架中，有些支架的溶胀和模量能够方便地解耦。除了能够快速筛选细胞 - 材料相互作用外，这些支架非常适合用于界面组织（例如骨软骨组织）的再生，这些组织从一种组织类型过渡到另一种组织类型。