In this project, we showed a novel idea to study cell communications. But still, there are several difficulties underlying it.
The biggest challenge for our microfluidic system is the coculture time. In order to produce two-cell droplets, droplet size is constrained at about 30microns. Which is only 8 fold the volume size than a cell. The smaller droplets, the less nutrition to maintain cell viability. Also, we don’t know how cells behave at single cell level and what differences are caused between single cells and multiple cells for cell communications in multicellular organisms often behave in cell population. To overcome this difficulty, we can modified our reporter cell lines to construct a rapid response reporter.
The second challenge for microfluidic system is the communication way of cells. There are many types of cell communications. Some are long-range signal transduction while some are adhesive transduction. We could not mimic all the situation of cell communications in cell level due to diversity of cell-cell interaction. The micro-well system may be good for researches on cell adhesion.
In general, we study Wnt secretion by genetic knockout for proof-of-principle. This is a very interesting biological questions in Wnt signaling. Although our final goal of genetic screening on Wnt secretion is still ongoing, we basically set up a microfluidic system compatible for mammalian cell line coculture. Due to lots of unknown in Wnt secretion, it is almost impossible to build a model to quantify the Wnt secretion behavior. But we can optimize our reporter to better fit the physical limitation of the microfluidic system.
We also developed a orthogonal method called micro-well planar system that can capture cell in a 2 dimensional plate. The diameter of micro-well is near 160um, which provide enough space for cell survival. But large environment also lower down the concentration of secreted signal. That will be one of our future directions.
In future, we will continue to build the microfluidic platform for Wnt signaling and other possible cell signaling pathway. And we would like to try more biological applications such as immune recognition, single-cell sequencing, biomaterial synthesis and etc.