Microencapsulated 3-dimensional sensor for single cell analysis
In the pursuit of understanding and developing treatments for human disease, scientists rely on in vitro studies of cells and tissues. Two modes of analysis are typically carried out: bulk analysis, in which a large population of cells is assessed, and single-cell analysis. Single-cell analysis allows for accurate resolution of kinetic responses, particularly important in electrically excitable cells, where integrated responses of multiple cells smoothes out heterogeneous and kinetically rapid waveforms. In many instances, only small numbers of cells are obtainable, and in general using fewer cells is less labor intensive and more efficient. However, methods to assess single cells are more technically challenging, in part due to the smaller signal generated. New developments in microfluidics have made it possible to meet these challenges.
We recently developed a novel imaging method for single-cell analysis. The method utilizes microfluidics to encapsulate cells with water-soluble fluorescent dyes that occupy the extracellular space between the cellmembrane and the polymer encasing. In this way, imaging of the encapsulated/dyed cell makes it possible to monitor exchanges between the extra- and intra-cellular environments in real time. Since dyes are available that are sensitive to a huge number of biologically important molecules, the method will have broad utility.
We recently focused on measurement of oxygen, calcium, and potassium of pancreatic islets, components that are central to the function of electrically excitable cells. Further developments will include establishing a high through-put screening format, and the simultaneous detection of multiple parameters. The technology will have particular utility in areas that focus on in vitro study of cells such as stem cell research, transplantation, cancer, and drug screening, spanning both fundamental and translational arenas.
- W. Chen, M. Lisowski, G. Khalil, I. R. Sweet, A. Q. Shen, Microencapsulated 3-dimensional sensor for the measurement of oxygen in single isolated pancreatic islets, PLoS ONE, 7(3): e33070, 2012. (doi:10.1371/journal.pone.0033070)
- W. Chen, Z. Shu, D. Zhang, D. Gao, I. Sweet, A.Q. Shen, Microencapsulation assisated cryo-preservation, to be submitted.