INRA, UR1268 Biopolymères Interactions Assemblages , F-44300 Nantes Cedex, France.
Biomacromolecules. 2014 May 12;15(5):1568-78. doi: 10.1021/bm401596m. Epub 2014 Apr 8.
We demonstrated the generation of pectin hydrogel microparticles having complex shapes either by combining the phenomenon of gelation and water diffusion-induced self-assembly in microfluidic channels (on-chip) or by the deformation of the pregelled droplets outside the channels (off-chip) at a fluid-fluid interface. We proved that by tuning the mode of pectin cross-linking (CaCl2 vs CaCO3) and the degree of shrinking (water content in the dimethyl carbonate (DMC) organic continuous phase) we can control the shape of the final particle. Sphere, doughnut, oblate ellipsoid, or mushroom-type morphologies were thus produced, demonstrating the ability to control the formation of anisotropic biopolymer-based hydrogel microparticles using microfluidics. Shape changes were explained by the redistribution of calcium ions in combination with the local Peclet number experienced by the microdroplets during the on-chip process. Moreover, during the off-chip process, the interplay between elastic and viscous forces for microdroplets entering the CaCl2-DMC interface caused deformation of the pregelled droplets to occur and therefore resulted in the formation of microparticles with a mushroom-like morphology.
我们展示了通过在微流道（片上）内结合凝胶化现象和水扩散诱导的自组装，或者通过在通道外的预凝胶液滴在流体-流体界面处变形（片外），来生成具有复杂形状的果胶水凝胶微球。我们证明，通过调整果胶交联模式（CaCl2 与 CaCO3）和收缩程度（二甲基碳酸酯（DMC）有机连续相中的含水量），我们可以控制最终颗粒的形状。因此，生成了球形、甜甜圈形、扁长椭球形或蘑菇形的形态，展示了使用微流控技术控制各向异性生物聚合物水凝胶微球形成的能力。通过结合微液滴在片上过程中经历的局部 Peclet 数，解释了形状变化。此外，在片外过程中，进入 CaCl2-DMC 界面的微液滴的弹性和粘性力之间的相互作用导致预凝胶液滴发生变形，从而导致形成具有蘑菇状形态的微球。
