Generation, detection and applications of in vitro oxygen gradients
June 5-9, 2018
Oxygen homeostasis is critical for the functioning of multicellular organisms. Deficiency of oxygen or hypoxia can lead to several pathological conditions such as ischemia, tumorigenesis and drug resistance. Most studies utilize specialized O2 incubators to generate singular oxygen concentrations that vary significantly from the physiological conditions where hypoxic gradients exist within the tissue e.g. in solid tumors. Current microfluidic technology using polydimethylsiloxane-based (PDMS) devices enables generation of such oxygen concentration gradients, but yield low-to-moderate spatial resolution, involve tedious device assembly and are not feasible for practical research or pharmaceutical screening. We have developed a novel and simplistic approach of reproducibly and rapidly generating stable biomimetic oxygen gradients with high spatial resolution and integrated detection capability. The microfluidic split and recombine strategy utilizing O2-rich and O2-depleted media allows generation of prolonged dissolved oxygen (DO) gradients while an underlying platinum based sensor layer (PtOEPK) allows real-time detection of DO gradients generated. Deposition of an approximately 5-7µm thick three-sided glass coating prevents multi-directional diffusion of ambient oxygen through PDMS maintaining the gradient stability for hours or days. Two variations of the gradient devices have been developed, one offering the ability to generate continuous gradients within a single channel while another containing multiple outlet chambers each maintaining a specific concentration of DO (Figure 1).
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Nitin Agarwal and Daud H. Khan, "Generation, detection and applications of in vitro oxygen gradients" in "Nanotechnology in Medicine II: Bridging Translational in vitro and in vivo Interfaces", Millicent Sullivan, PhD, University of Delaware, USA Josué Sznitman, Dr. Sc., Technion-Israel Institute of Technology, Israel Lola Eniola-Adefeso, PhD, University of Michigan, USA Srivatsan Kidambi, PhD, University of Nebraska - Lincoln, USA Eds, ECI Symposium Series, (2018). http://dc.engconfintl.org/nanotech_med_ii/30