Department of Electrical and Computer Engineering, Texas A&M University, College Station, TX 77843, USA.
Korea Institute of Machinery and Materials, Daegu Research Center for Medical Devices and Rehabilitation, Daegu, 42994, Republic of Korea.
Lab Chip. 2019 Dec 21;19(24):4128-4138. doi: 10.1039/c9lc00850k. Epub 2019 Nov 22.
Microalgae are promising alternatives to petroleum as renewable biofuel sources, however not sufficiently economically competitive yet. Here, a label-free lateral dielectrophoresis-based microfluidic sorting platform that can digitally quantify and separate microalgae into six outlets based on the degree of their intracellular lipid content is presented. In this microfluidic system, the degree of cellular lateral displacement is inversely proportional to the intracellular lipid level, which was successfully demonstrated using Chlamydomonas reinhardtii cells. Using this functionality, a quick digital quantification of sub-populations that contain different intracellular lipid level in a given population was achieved. In addition, the degree of lateral displacement of microalgae could be readily controlled by simply changing the applied DEP voltage, where the level of gating in the intracellular lipid-based sorting decision could be easily adjusted. This allowed for selecting only a very small percentage of a given population that showed the highest degree of intracellular lipid content. In addition, this approach was utilized through an iterative selection process on natural and chemically mutated microalgal populations, successfully resulting in enrichment of high-lipid-accumulating microalgae. In summary, the developed platform can be exploited to quickly quantify microalgae lipid distribution in a given population in real-time and label-free, as well as to enrich a cell population with high-lipid-producing cells, or to select high-lipid-accumulating microalgal variants from a microalgal library.
微藻作为可再生生物燃料的替代物，具有广阔的应用前景，然而，其经济竞争力还不够强。本研究提出了一种无需标记的侧向介电泳微流控分选平台，该平台可以根据细胞内脂质含量的程度，将微藻数字量化并分离到六个出口。在这个微流控系统中，细胞的侧向位移程度与细胞内脂质水平成反比，这一点已通过莱茵衣藻细胞得到了成功验证。利用这一功能，可以快速对特定群体中具有不同细胞内脂质水平的亚群进行数字量化。此外，通过简单改变施加的介电泳电压，很容易控制微藻的侧向位移程度，从而可以轻松调整基于细胞内脂质的分选决策的门控水平。这使得可以只选择给定群体中具有最高细胞内脂质含量的一小部分。此外，本方法通过对天然和化学诱变的微藻群体进行迭代选择过程，成功地富集了高脂质积累的微藻。总之，所开发的平台可以用于实时、无标记地快速量化给定群体中微藻的脂质分布情况，以及从微藻库中富集高产脂质的微藻变体或从微藻库中筛选高产脂质的微藻变体。
