Ström Oskar E, Beech Jason P, Tegenfeldt Jonas O
Division of Solid State Physics, Department of Physics, Lund University, Lund, Sweden.
Lab Chip. 2023 Mar 28;23(7):1779-1793. doi: 10.1039/d2lc01051h.
We observe regular patterns emerging across multiple length scales with high-concentration DNA solutions in microfluidic pillar arrays at low Reynolds numbers and high Deborah numbers. Interacting vortices between pillars lead to long-range order in the form of large travelling waves consisting of DNA at high concentration and extension. Waves are formed in quadratic arrays of pillars, while randomizing the position of the pillar in each unit cell of a quadratic array leads to suppression of the long-range patterns. We find that concentrations exceeding the overlap concentration of the DNA enables the waves, and exploring the behavior of the waves as a function of flow rate, buffer composition, concentration and molecular length, we identify elastic effects as central to the origin of the waves. Our work may not only help increase the low throughput that often limits sample processing in microfluidics, it may also provide a platform for further studies of the underlying viscoelastic mechanisms.
在低雷诺数和高德博拉数条件下，我们观察到微流控柱阵列中高浓度DNA溶液在多个长度尺度上呈现出规则模式。柱间相互作用的涡旋导致了由高浓度和伸展的DNA形成的大传播波形式的长程有序。波在柱的二次阵列中形成，而随机化二次阵列每个晶胞中柱的位置会导致长程模式的抑制。我们发现，超过DNA重叠浓度的浓度能够形成波，通过研究波作为流速、缓冲液组成、浓度和分子长度的函数的行为，我们确定弹性效应是波产生的核心。我们的工作不仅可能有助于提高经常限制微流控中样品处理的低通量，还可能为进一步研究潜在的粘弹性机制提供一个平台。
