Fabrication of Hydrogels with a Stiffness Gradient Using Limited Mixing in the Hele-Shaw Geometry
Fabrication of Hydrogels with a Stiffness Gradient Using Limited Mixing in the Hele-Shaw Geometry
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DOI：
10.1007/s11340-018-0416-1
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发表时间：
2019-11-01
影响因子：
2.4
通讯作者：
Ryu, S.
中科院分区：
文献类型：
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作者：
Lee, D.;Golden, K.;Ryu, S.
具有刚度梯度的水凝胶基质已被用作细胞外基质（ECM）的替代物，以研究细胞如何响应其周围基质的刚度。已经提出了各种制造方法来在水凝胶基底中产生刚度梯度，并且其中一些依赖于在光聚合之前在预聚物溶液中产生浓度梯度。这样做的一种简单方法是在由两个玻璃表面形成的狭窄限制中聚结不同刚度值的两个预聚物溶液滴，然后使用紫外（UV）光照射诱导聚合，如Lo等人[Biophys. J. 2000，79：144-152]。我们已经改进了他们的方法，使调制所获得的刚度梯度和特征制造聚丙烯酰胺（PAAM）凝胶。我们使用实验室构建的Hele-Shaw细胞装置和具有超疏水屏障的玻璃表面控制两种预聚物滴的聚结和混合持续时间。液滴之间的有限混合产生了凝胶成分的浓度梯度，其通过基于UV的光聚合转化为刚度梯度。原子力显微镜（AFM）的压痕表明，所制造的凝胶的刚度梯度区的中心和区域的宽度增加的混合时间。
Hydrogel substrates with a stiffness gradient have been used as a surrogate of the extracellular matrix (ECM) to investigate how cells respond to the stiffness of their surrounding matrix. Various fabrication methods have been proposed to create a stiffness gradient in the hydrogel substrate, and some of them rely on generating a concentration gradient in a prepolymer solution before photo-polymerization. One easy way to do so is to coalesce two prepolymer solution drops of different stiffness values in a narrow confinement formed by two glass surfaces and then to induce polymerization using ultraviolet (UV) light irradiation, as proposed by Lo et al. [Biophys. J. 2000, 79:144-152]. We have improved their method to enable modulating the obtained stiffness gradient and characterized fabricated polyacrylamide (PAAM) gels. We controlled the coalescence and mixing duration of two prepolymer drops using the lab-built Hele-Shaw cell device and glass surfaces with a superhydrophobic barrier. Limited mixing between the drops created a concentration gradient of the gel ingredient, which was converted to a stiffness gradient by UV-based photo-polymerization. Atomic force microscopy (AFM) indentation showed that the fabricated gels had the stiffness gradient zone at the center and that the width of the zone increased with the mixing duration.