Department of Chemical Engineering and Bioengineering, University of New Hampshire, Durham, NH, 03824, USA.
Department of Chemistry, University of New Hampshire, Durham, NH, 03824, USA.
Sci Rep. 2023 Sep 9;13(1):14896. doi: 10.1038/s41598-023-41947-z.
Thermoresponsive polysaccharide-based materials with tunable transition temperatures regulating phase-separated microdomains offer substantial opportunities in tissue engineering and biomedical applications. To develop novel synthetic thermoresponsive polysaccharides, we employed versatile chemical routes to attach hydrophobic adducts to the backbone of hydrophilic dextran and gradually increased the hydrophobicity of the dextran chains to engineer phase separation. Conjugating methacrylate moieties to the dextran backbone yielded a continuous increase in macromolecular hydrophobicity that induced a reversible phase transition whose lower critical solution temperature can be modulated via variations in polysaccharide concentration, molecular weight, degree of methacrylation, ionic strength, surfactant, urea and Hofmeister salts. The phase separation is driven by increased hydrophobic interactions of methacrylate residues, where the addition of surfactant and urea disassociates hydrophobic interactions and eliminates phase transition. Morphological characterization of phase-separated dextran solutions via scanning electron and flow imaging microscopy revealed the formation of microdomains upon phase transition. These novel thermoresponsive dextrans exhibited promising cytocompatibility in cell culture where the phase transition exerted negligible effects on the attachment, spreading and proliferation of human dermal fibroblasts. Leveraging the conjugated methacrylate groups, we employed photo-initiated radical polymerization to generate phase-separated hydrogels with distinct microdomains. Our bottom-up approach to engineering macromolecular hydrophobicity of conventional hydrophilic, non-phase separating dextrans to induce robust phase transition and generate thermoresponsive phase-separated biomaterials will find applications in mechanobiology, tissue repair and regenerative medicine.
具有可调转变温度的温敏多糖基材料可调节相分离微区，为组织工程和生物医学应用提供了巨大的机会。为了开发新型合成温敏多糖，我们采用了多种化学途径将疏水性加合物连接到亲水性葡聚糖的主链上，并逐渐增加葡聚糖链的疏水性，以进行相分离工程。将甲基丙烯酰基接枝到葡聚糖主链上，会导致大分子疏水性连续增加，从而诱导可逆的相转变，其低临界溶液温度可以通过改变多糖浓度、分子量、甲基丙烯酰化程度、离子强度、表面活性剂、尿素和霍夫迈斯特盐来调节。相分离是由甲基丙烯酰基残基的疏水性相互作用增加驱动的，其中表面活性剂和尿素的加入会破坏疏水性相互作用并消除相转变。通过扫描电子显微镜和流动成像显微镜对相分离的葡聚糖溶液进行形态学表征，揭示了相转变时微区的形成。这些新型温敏葡聚糖在细胞培养中表现出良好的细胞相容性，相转变对人皮肤成纤维细胞的附着、铺展和增殖几乎没有影响。利用接枝的甲基丙烯酰基，我们采用光引发自由基聚合生成具有明显微区的相分离水凝胶。我们采用这种自下而上的方法来工程化常规亲水性、非相分离葡聚糖的大分子疏水性，以诱导强相转变并生成温敏相分离生物材料，这将在机械生物学、组织修复和再生医学中得到应用。
