Stepwise construction of dynamic microscale concentration gradients around hydrogel-encapsulated cells in a microfluidic perfusion culture device

Inside living organisms, concentration gradients dynamically change as biological processes progress. Therefore, methods to construct dynamic microscale concentration gradients in a spatially controlled manner are needed to provide more realistic research environments. Here, we report a novel method for the construction of dynamic microscale concentration gradients in a stepwise manner around cells in micropatterned hydrogel. In our method, cells are encapsulated in a photodegradable hydrogel formed inside a microfluidic perfusion culture device, and perfusion microchannels are then fabricated in the hydrogel by micropatterned photodegradation. The cells in the micropatterned hydrogel can then be cultured by perfusing culture medium through the fabricated microchannels. By using this method, we demonstrate the simultaneous construction of two dynamic concentration gradients, which allowed us to expose the cells encapsulated in the hydrogel to a dynamic microenvironment.

在活体内，随着生物学过程的推进，浓度梯度会发生动态变化。因此，开发能够以空间可控方式构建动态微尺度浓度梯度的方法，可为研究提供更贴近真实生理状态的实验环境。本研究报道了一种新型方法，可在微图案化水凝胶（micropatterned hydrogel）内的细胞周围以分步方式构建动态微尺度浓度梯度。在该方法中，我们将细胞包埋于微流体灌注培养装置（microfluidic perfusion culture device）内部形成的光降解水凝胶（photodegradable hydrogel）中，随后通过微图案化光降解（micropatterned photodegradation）工艺在水凝胶内部制备灌注微通道。随后可通过向制备好的微通道中灌注培养基，对微图案化水凝胶内的细胞进行培养。借助该方法，我们成功实现了两种动态浓度梯度的同步构建，可使包埋于水凝胶内的细胞处于动态微环境中。