Gong Youping, Chen Honghao, Li Wenxin, Zhou Chuanping, Zhou Rougang, Zhao Haiming, Shao Huifeng
School of Mechanical Engineering, Hangzhou Dianzi University, Hangzhou 310018, China.
State Key Laboratory of Fluid Power and Mechatronic Systems, School of Mechanical Engineering, Zhejiang University, Hangzhou 310027, China.
Materials (Basel). 2022 Mar 20;15(6):2305. doi: 10.3390/ma15062305.
Hydrogel microspheres are widely used in tissue engineering, such as 3D cell culture and injection therapy, and among which, heterogeneous microspheres are drawing much attention as a promising tool to carry multiple cell types in separated phases. However, it is still a big challenge to fabricate heterogeneous gel microspheres with excellent resolution and different material components in limited sizes. Here, we developed a multi-channel dynamic micromixer, which can use active mechanical mixing to achieve rapid mixing with multi-component materials and extrude the homogenized material. By changing the flow rate ratio of the solutions of the two components and by rapidly mixing in the micromixer, real-time concentration change of the mixed material at the outlet could be monitored in a process so-called "gradient printing". By studying the mixing efficiency of the micromixer, its size and process parameters were optimized. Using the novel dynamic gradient printing method, the composition of the hydrogel microspheres can be distributed in any proportion and alginate heterogeneous gel microspheres with adjustable cell concentration were fabricated. The effects of cell concentration on cell viability and proliferation ability under three-dimensional culture conditions were also studied. The results showed that cells have very low death rate and can exchange substances within the microspheres. Due to the micromixing ability of the micromixers, the demand for biological reagents and materials such as cells, proteins, cytokines and other materials could be greatly reduced, which helps reduce the experimental cost and improve the feasibility of the method in practical use. The heterogeneous gel microsphere can be greatly valuable for research in various fields such as analytical chemistry, microarray, drug screening, and tissue culture.
水凝胶微球广泛应用于组织工程，如三维细胞培养和注射治疗，其中，异质微球作为一种在分离相中携带多种细胞类型的有前途的工具备受关注。然而，制造具有优异分辨率且尺寸有限、材料成分不同的异质凝胶微球仍然是一个巨大的挑战。在此，我们开发了一种多通道动态微混合器，它可以利用主动机械混合实现与多组分材料的快速混合，并挤出均匀化的材料。通过改变两种组分溶液的流速比，并在微混合器中快速混合，可以在一个所谓的“梯度打印”过程中监测出口处混合材料的实时浓度变化。通过研究微混合器的混合效率，对其尺寸和工艺参数进行了优化。利用这种新型的动态梯度打印方法，水凝胶微球的成分可以按任何比例分布，并制备出细胞浓度可调的藻酸盐异质凝胶微球。还研究了细胞浓度在三维培养条件下对细胞活力和增殖能力的影响。结果表明，细胞死亡率极低，且能在微球内进行物质交换。由于微混合器的微混合能力，可以大大降低对细胞、蛋白质、细胞因子等生物试剂和材料的需求，这有助于降低实验成本，提高该方法在实际应用中的可行性。这种异质凝胶微球在分析化学、微阵列、药物筛选和组织培养等各个领域的研究中可能具有巨大价值。
