Nalin Francesco, Tirelli Maria Celeste, Garstecki Piotr, Postek Witold, Costantini Marco
Institute of Physical Chemistry, Polish Academy of Sciences, 44/52 ul. Kasprzaka, 01-224 Warsaw, Poland.
Broad Institute of MIT and Harvard, Merkin Building, 415 Main St, Cambridge, MA 02142, USA.
Lab Chip. 2023 Dec 20;24(1):113-126. doi: 10.1039/d3lc00658a.
We present tuna-step, a novel microfluidic module based on step emulsification that allows for reliable generation of droplets of different sizes. Until now, sizes of droplets generated with step emulsification were hard-wired into the geometry of the step emulsification nozzle. To overcome this, we incorporate a thin membrane underneath the step nozzle that can be actuated by pressure, enabling the tuning of the nozzle size on-demand. By controllably reducing the height of the nozzle, we successfully achieved a three-order-of-magnitude variation in droplet volume without adjusting the flow rates of the two phases. We developed and applied a new hydrophilic surface modification, that ensured long-term stability and prevented swelling of the device when generating oil-in-water droplets. Our system produced functionally graded soft materials with adjustable porosity and material content. By combining our microfluidic device with a custom 3D printer, we generated and extruded oil-in-water emulsions in an agarose gel bath, creating unique self-standing 3D hydrogel structures with porosity decoupled from flow rate and with composition gradients of external phases. We upscaled tuna-step by setting 14 actuatable nozzles in parallel, offering a step-emulsification-based single chip solution that can accommodate various requirements in terms of throughput, droplet volumes, flow rates, and surface chemistry.
我们展示了金枪鱼步移式微流控模块，这是一种基于分步乳化的新型微流控模块，能够可靠地生成不同大小的液滴。到目前为止，分步乳化产生的液滴大小由分步乳化喷嘴的几何形状决定。为克服这一问题，我们在分步喷嘴下方加入了一层可通过压力驱动的薄膜，从而能够按需调整喷嘴大小。通过可控地降低喷嘴高度，我们成功实现了液滴体积三个数量级的变化，而无需调整两相的流速。我们开发并应用了一种新的亲水性表面改性方法，该方法确保了长期稳定性，并防止在生成水包油液滴时装置发生膨胀。我们的系统生产出了具有可调孔隙率和材料含量的功能梯度软材料。通过将我们的微流控装置与定制的3D打印机相结合，我们在琼脂糖凝胶浴中生成并挤出了水包油乳液，创造出了独特的自立式3D水凝胶结构，其孔隙率与流速解耦，且外部相具有成分梯度。我们通过并行设置14个可驱动喷嘴对金枪鱼步移式微流控模块进行了放大，提供了一种基于分步乳化的单芯片解决方案，该方案能够满足在通量、液滴体积、流速和表面化学方面的各种要求。
