Spatiotemporal NF-κB dynamics encodes the position, amplitude, and duration of local immune inputs.

Infected cells communicate through secreted signaling molecules like cytokines, which carry information about pathogens. How differences in cytokine secretion affect inflammatory signaling over space and how responding cells decode information from propagating cytokines are not understood. By computationally and experimentally studying NF-κB dynamics in cocultures of signal-sending cells (macrophages) and signal-receiving cells (fibroblasts), we find that cytokine signals are transmitted by wave-like propagation of NF-κB activity and create well-defined activation zones in responding cells.

Automated Microfluidic System for Dynamic Stimulation and Tracking of Single Cells.

Dynamic environments determine cell fate decisions and function. Understanding the relationship between extrinsic signals on cellular responses and cell fate requires the ability to dynamically change environmental inputs in vitro, while continuously observing individual cells over extended periods of time. This is challenging for nonadherent cells, such as hematopoietic stem and progenitor cells, because media flow displaces and disturbs such cells, preventing culture and tracking of single cells.

A microfluidic device for measuring cell migration towards substrate-bound and soluble chemokine gradients.

Cellular locomotion is a central hallmark of eukaryotic life. It is governed by cell-extrinsic molecular factors, which can either emerge in the soluble phase or as immobilized, often adhesive ligands. To encode for direction, every cue must be present as a spatial or temporal gradient.

Automated co-culture system for spatiotemporal analysis of cell-to-cell communication.

We present a microfluidic co-culture system that generates localized and precisely formulated immune signals among a population of cells, enabling spatiotemporal analysis of paracrine signal transmission between different cell types. The automated system allows us to create temporally modulated chemical inputs that can be delivered to single signal-transmitting and receiving cells in a highly controlled way. Using this system we stimulated a single macrophage with brief pulses of bacterial LPS and observed the macrophage transmitted TNF signal propagating in a population of fibroblasts via NF-κB activation.

Real-time tracking, retrieval and gene expression analysis of migrating human T cells.

Dynamical analysis of single-cells allows assessment of the extent and role of cell-to-cell variability, however traditional dish-and-pipette techniques have hindered single-cell analysis in quantitative biology. We developed an automated microfluidic cell culture system that generates stable diffusion-based chemokine gradients, where cells can be placed in predetermined positions, monitored via single-cell time-lapse microscopy, and subsequently be retrieved based on their migration speed and directionality for further off-chip gene expression analysis, constituting a powerful platform for multiparameter quantitative studies of single-cell chemotaxis. Using this system we studied CXCL12-directed migration of individual human primary T cells.

Flow-switching allows independently programmable, extremely stable, high-throughput diffusion-based gradients.

An automated microfluidic cell culture platform that creates and maintains independently programmable diffusion-based gradients is reported. Temporal modulation of the source and sink flow patterns allow generation of extremely stable spatial gradients. We developed a system that integrates 30 parallel gradients in a single device, with 10 different chemical formulations and 3 replicates.