Conference Agenda

Microfluidics & Miniaturization - the Teenage Years are Over

Andreas Manz

Korea Institute of Science and Technolgy (KIST)

.After a brief overview of historic micro- and nanotechnology for “lab on chip” devices, I will focus on 2 examples of near market applications:

Bacteria causing infections can be identified by detecting specific DNA sequences. This method is widely used and has a high degree of specificity. However, for this purpose, the micro organisms will have to be captured, and it is not clear whether they are dead or alive. Metabolite studies have the advantage that remote evidence for live cells can be identified.

I will present portable equipment for volatile metabolite quantification, based on multi-capillary GC and ion-mobility detection [1]. The raw data is mathematically treated to receive best discrimination of patient groups. Applications for diagnostics of lung infections and lung cancer will be shown. In addition, a chip-based hand held real-time PCR instrument will be presented. A "virtual reactor" approach, i.e., a free droplet in oil, is used for thermal cycling and subsequent melting temperature profiling of the PCR product [2].

Furthermore, there will be a few other examples of recent microfluidic work.

[1] Perl, T., Vautz, W., Nolte, J., Baumbach, J.I. & Quintel, M. Ion mobility spectrometry of human pathologic bacteria - metabolic profiling by volatile organic compounds. Infection 37, 24-24 (2009).

[2] Pavel Neuzil, Chunyan Zhang, Juergen Pipper, Sharon Oh, Lang Zhuo, Ultra fast miniaturized real-time PCR: 40 cycles in less than six minutes. Nucleic Acids Research, 2006, Vol. 34, doi:10.1093/nar/gkl416

Microfluidic single-cell analysis: NF-kappaB signaling as a case study

Savas Tay

ETH Zürich

Microfluidics is a powerful technology that is impacting biomedical sciences in a profound way. I will talk about microfluidic single cell analysis in the context of NF-kappaB signaling dynamics. NF-kappaB is one of the better studied innate immune pathways, albeit mostly using traditional, population averaged assays. Although the individual components of NF-kappaB are (relatively) well understood, how these components act as a system at the cellular level has remained an open question. Using an automated high-throughput microfluidic cell culture system and single-cell microscopy, we measured and quantified NF-kappaB transcription factor activity in thousands of live cells under TNF-alpha doses covering four orders of magnitude (Nature 466, 267, 2010). In contrast to population assays, NF-kappaB activation is found to be a switch-like process at the single cell level, with fewer cells responding at lower doses. The activated cells up-regulate early genes independent of the TNF-alpha concentration in line with the digital activation of NF-kappaB, while only high dose stimulation results in the expression of late-term genes. Using our comprehensive data, we developed a mathematical model that reproduces both the digital and analog dynamics as well as the gene expression profiles at all measured conditions, constituting a broadly applicable model of NF-kappaB signaling. These results highlight the value of high-throughput quantitative measurements at the single-cell level in understanding how biological systems operate. I will also briefly talk about other aspects of NF-kappaB signaling under LPS mediated TLR4 activation, and collective migration characteristics of cells in 2-D microfluidic environments.

The Envirostat: A Lab-on-a-Chip Reactor Concept for Single Cell Biotechnology

Hendrik Kortmann

Novartis Vaccines, Germany

Cells, equal or not equal? That is the question pursued in this presented thesis. A question not easily answerable by population data reporting averaged read outs of millions of cells. Here spatiotemporal single cell analysis under fully controlled environmental conditions was the aim, approached by the design, construction and use of a lab-on-a-chip reactor concept, the Envirostat.

To accomplish single cell cultivation under environmental controlled and constant conditions, the commercially lab on a chip was adapted. A new interface was constructed for fluidic and electric coupling of the fragile lab-on-a-chip system. Cultivation temperature during cell trapping was controlled by combination of the negative dielectrophoresis trapping immanent Joule heating and an integrated temperature-device. The Envirostat concept of constant environmental conditions during cultivation of a single yeast cell was simulated by computation fluid dynamics. Cultivations starting from single yeast cells in the Envirosta demonstrate its usability as bioreactor.

Furthermore, the combination of the Envirostat with confocal microscopy enabled real time protein secretion rate monitoring of trapped fission yeast cells. The results indicated that few (four) eGFP secreting cells can be reliably differentiated from non-secreting cells with the promising prospect to gain detailed time resolved information of protein secretion kinetics of an individual cell.

Summing up, in the presented thesis the Envirostat for the analysis of few down to a single cell was developed, characterized, and its usability shown.