Cell-laden hydrogel microcapsules enable the high-throughput production of cell aggregates, which are relevant for three-dimensional tissue engineering and drug screening applications. However, current microcapsule production strategies are limited by their throughput, multistep protocols, and limited amount of compatible biomaterials. We here present a single-step process for the controlled microfluidic production of single-core microcapsules using enzymatic outside-in cross-linking of tyramine-conjugated polymers. It was hypothesized that a physically, instead of the conventionally explored biochemically, controlled enzymatic cross-linking process would improve the reproducibility, operational window, and throughput of shell formation. Droplets were flown through a silicone delay line, which allowed for highly controlled diffusion of the enzymatic cross-linking initiator. The microcapsules' cross-linking density and shell thickness is strictly depended on the droplet's retention time in the delay line, which is predictably controlled by flow rate. The here presented hydrogel cross-linking method allows for facile and cytocompatible production of cell-laden microcapsules compatible with the formation and biorthogonal isolation of long-term viable cellular spheroids for tissue engineering and drug screening applications.

载有细胞的水凝胶微胶囊可实现细胞聚集体的高通量生产，这与三维组织工程和药物筛选应用有关。但是，当前的微胶囊生产策略受到其通量，多步骤方案和有限数量的兼容生物材料的限制。我们在这里提出了一个单步过程，可利用酪胺偶联聚合物的酶促外-内交联来控制单核微胶囊的微流控生产。据推测，物理地而不是常规地探索的生物化学地，受控的酶交联过程将改善壳形成的可再现性，操作窗口和生产量。液滴流过硅胶延迟线，从而可以高度控制地扩散酶促交联引发剂。微胶囊的交联密度和壳厚度严格取决于液滴在延迟线中的保留时间，延迟时间可预测地由流速控制。本文介绍的水凝胶交联方法可以轻松，细胞相容地生产载有细胞的微囊，与用于组织工程和药物筛选应用的长期可行细胞球体的形成和生物正交分离兼容。