Single Cell Interrogation using Optofluidic Platforms for Systems Immunology

The main objective of this report is to demonstrate novel engineering technologies to investigate regulatory mechanisms of systems immunology in a time-dependent and high-throughput manner. Understanding of immune system behavior is crucial for accurate prognosis of infections and identification of diseases at early stage. An ultimate goal of biomedical engineering is to develop predictive models of immune system behavior in tissue, which necessitates a comprehensive map of dynamic (time-dependent) input-output relationships at the individual cell level. Traditionally, biochemical analysis on the cell signaling is obtained from bulky cell ensembles which average over relevant individual cell response. The response consists firstly of signaling protein (cytokine) secretions which are released during a disease state and which are used to activate the immune system to respond to the disease. We investigate the cytokine secretion dynamics of a single immune cell in response to the stimulant using automated and comprehensive optofluidic platforms. These platforms enable survival and manipulation of single cells in compartments having compatible sizes with cells as well as provide precise control over the type, dose and time-course of the stimulant. The cytokine secretion dynamics of single cell are typically explained by measuring the types, rates, frequencies and concentrations of various cytokines. For the quantitative measurements, label free localized surface plasmon resonance (LSPR) based biosensor can be integrated within the microfluidic device. Microfluidic channels can confine secreted cytokines in compartments, minimize dilution effects and increase detection sensitivity for label free plasmonic biosensing. The direct application of LSPR to in-situ live cell function analysis is still in its infancy and use of such in-situ, real time, and label free biodetection will effortlessly provide high-throughput quantitative bioanalysis for understanding immune system behavior.