ME Seminar - Microfluidic manipulation of multiphasic liquid-liquid phase-separated (LLPS) systems for in vitro biological models

Guest Speaker: Prof. KONG Tiantian

Department of Biomedical Engineering, Shenzhen University, China

Prof. KONG is currently a professor in the Department of Biomedical Engineering at Shenzhen University China. As the first or corresponding author, she has contributed to more than 100 papers published in high-impact journals, including Nature Communications, Proceedings of the National Academy of Sciences (PNAS), Advanced Materials, Angewandte Chemie, and others. She has served as Editorial broad Member/Guest Editor for high-impact journal Microengineering and Nanosystems (MINE), Green Energy Environment (GEE) and Small. In 2020, she was granted the "Young Scientist Award" at the Microsystem and Nanoengineering Summit. Further, in 2022, she was named an "Emerging Investigator" by Soft Matter (RSC). Later that year, she also received the Second Prize of the Science and Technology Award from the Chemical Industry and Engineering Society of China (CIESC). In 2023, she received a competitive recognition of the “Excellent Young Scholar” of National Natural Science Foundation of China (NSFC).

Nature has demonstrated the power to synthesize chemicals, achieve diverse functions and construct complicated materials through aqueous compartmentalization. In living cells, biological condensates, phase-separated membrane-less compartments, are crucial in regulating biochemical reactions and orchestrating cellular functions. Inspired by these natural systems, synthetic condensates exploit the principles of liquid-liquid phase separation (LLPS) to selectively concentrate or exclude various biomolecules, such as peptides, proteins, nucleic acids, and even bacteria. By integrating LLPS with microfluidics technology, which allows precise control of flow and distinct interfaces, we create detailed and functional in vitro models. We combine segregative and associative LLPS methods to generate hierarchically compartmentalized structures and control fluid dynamics to form “stagnation rings” that maintain core-shell compartments for biochemical reactions, including protein and nucleic acid segregation, enrichment, and amplification. We engineer coacervates that enhance biomolecule concentration, improving detection sensitivity, with DNA amplification in coacervate droplets showing a strong correlation between DNA copy number and fluorescent droplet count, thus reducing detection limits. Inspired by the hanging drop method, we use microfluidics to assemble GUV-based protocells into arrays connected by lipid bilayers, facilitating cell-cell and cell-environment communication and enabling the creation of hybrid cell/protocell spheroids for new biomaterials and in vitro models. Additionally, we exploit interfaces of multiphase LLPS to enable freeform three-dimensional printing of liquid-liquid architectures compatible with viable cells. The synergy between multiple LLPS and microfluidics has the potential to create more detailed and functional in vitro models, significantly enhancing our ability to study and replicate complex biological processes.