ACS Appl Mater Interfaces. 2018 May 2;10(17):14399-14409. doi: 10.1021/acsami.8b00802. Epub 2018 Apr 23.
Surfaces engineered to "specifically capture" and "release on demand" analytes ranging from biomolecules to cells find niche applications in areas such as diagnostics and detection. Utilization of a disulfide-based linker as a building block allows fabrication of a novel hydrogel-based platform that incorporates a "catch and release" attribute. Hydrogels incorporating pyridyl disulfide groups as thiol-reactive handles were prepared by photopolymerization in the presence of a poly(ethylene glycol) (PEG)-based cross-linker. A range of bulk and micropatterned hydrogels with varying amounts of the reactive group were prepared using PEG-based monomers with different chain lengths. Thiol-containing molecules were conjugated to these hydrogels through the thiol-disulfide exchange reaction under ambient conditions with high efficiencies, as determined by UV-vis spectroscopy. Facile conjugation of a thiol-containing fluorescent dye, namely 4,4-difluoro-1,3,5,7-tetramethyl-8-[(10-mercapto)]-4-bora-3 a,4 a-diaza- s-indacene, was demonstrated, followed by its effective cleavage in the presence of dithiothreitol (DTT), a thiol-containing disulfide-reducing agent. Conjugation of a biotin-containing ligand onto the hydrogels allowed specific binding of protein extravidin when exposed to a mixture of extravidin and bovine serum albumin. The bound protein could be released from the hydrogel by simple exposure to a DTT solution. Likewise, hydrogels modified with a cell-adhesive peptide unit containing the RGD sequence acted as favorable substrates for cellular attachment. Incubation of these cell-attached hydrogel surfaces in a DTT-containing solution leads to facile detachment of cells from the surfaces, while retaining a high level of cell viability. It can be envisioned that the benign nature of these hydrogels, their facile fabrication, and modular functionalization will make them attractive platforms for many applications.
经过专门设计，可以“特异性捕获”和“按需释放”分析物的表面，其范围涵盖从生物分子到细胞，在诊断和检测等领域找到了应用的切入点。利用二硫键作为构建块，可以制造出一种新型水凝胶基平台，该平台具有“捕获和释放”的属性。含有吡啶二硫键基团的水凝胶作为巯基反应性配体，通过在聚乙二醇（PEG）基交联剂存在下的光聚合来制备。使用具有不同链长的 PEG 基单体，制备了一系列具有不同反应性基团含量的块状和微图案化水凝胶。含有巯基的分子通过在环境条件下通过硫醇-二硫化物交换反应与这些水凝胶连接，通过紫外可见光谱确定具有很高的效率。成功地将一种含有巯基的荧光染料，即 4,4-二氟-1,3,5,7-四甲基-8-[(10-巯基)]-4-硼-3a,4a-二氮杂 s-茚，通过硫醇-二硫化物交换反应连接到水凝胶上，随后在含有二硫苏糖醇（DTT）的条件下，DTT 是一种含有巯基的二硫还原剂，该荧光染料可以有效地被切割。将含有生物素的配体连接到水凝胶上，当暴露于外啡肽和牛血清白蛋白的混合物时，允许特定结合蛋白外啡肽。通过简单地暴露于 DTT 溶液，可以将结合的蛋白质从水凝胶上释放。同样，经过修饰的水凝胶含有含有 RGD 序列的细胞黏附肽单元，可以作为细胞附着的有利底物。将这些附着细胞的水凝胶表面在含有 DTT 的溶液中孵育，可导致细胞从表面容易地脱离，同时保持高水平的细胞活力。可以想象，这些水凝胶的良性性质、易于制造和模块化功能化，将使它们成为许多应用的有吸引力的平台。
