Microfluidic platform for the initiation and investigation of cellular interactions on a single-cell level

Cellular interactions as they occur in the stem cell niche or in context with leukocyte activation are effective mechanisms for the regulation of cellular states in vivo. The analysis of the underlying principles is of high clinical interest. Unfortunately, conventional applications used for addressing the related questions often pool biological data of cellular subpopulations or provide only end point analyses of signal transduction processes. This leads to blurred data or ignores important information from the dynamics of cellular behaviour, respectively. Here, we present a novel microfluidic platform for the initiation and analysis of cellular interactions on a single-cell level. We used the system to stimulate single T cells with anti-CD3/anti-CD28-presenting microbeads and analyzed the cytosolic calcium signal simultaneously. T cell activation was examined 16 - 24 h after stimulus presentation and was correlated with the previously recorded calcium signal. A signif icant difference between the calcium patterns of activated and non-activated cells was detected. This shows that the dynamics of a cellular response can provide useful information about the specific physiological state of a cell. The described technique accounts for this finding and could help to diversify our view of intercellular communication.