Microfluidic Pumping System

Office of Science and Engineering (OSEL)/Division of Biology, Chemistry, and Materials Science (DBCMS) needs to perform genetic characterization (gene expression analysis) by testing mammalian cell response to various polymeric and/or biological products from metal implants—expeditiously, to develop in vitro models for metal testing. To do this, the department requires a microfluidic system that allows the user to grow and visualize cells for multiple days and weeks with intermittent or continuous exposure to different alloys. Additionally, the response to metals must be testable under a live-imaging microscope or fluorescent microscope. At present DBCMS does not have the capacity (with regards to instrumentation) to conduct this research. In addition, we do not have the combination of this instrumentation within our facilities or accessible for research purposes within OSEL/Center for Devices and Radiological Health (CDRH). Therefore, we currently have no adequate means to test and measure cellular responses to device materials for prolonged periods of testing, in vitro. Examples of OSEL projects which are currently stalled or cannot be initiated due to the absence of a microfluidic pumping system access: a. Measuring genetic changes in response to wound-healing products following exposure to anti-microbial metals in wound dressings b. In vitro cell response to textured implants – changes in cytokines and growth factors c. Immune cell responses to metals from implanted devices contributing to chronic inflammation due to alloy exposure. d. Ex vivo and in vitro immune cell response to device materials e. Changes in telomere length due to metal exposure To characterize biological effects from metals, anti-microbial, and synthetic materials-used with medical devices- on mammalian cells, these cells must be exposed to these materials at different frequencies to examine phenotypic and genotypic changes in biology. There are no other methods to examine and quantitate the expression of specific gene products from cells in real-time- following exposure to alloys- without the use of a microfluidic pumping system to maintain continuous flow surrounding mammalian cells. An alternative albeit less representative methodology would be traditional 1-dimensional cell growth in tissue culture plates/flasks. But, with metal implants – the constant flow of particles and metal ions over cells, results in changes to cell activity that cannot be captured through stagnant cell culture systems. Additionally, there are changes in oxygen, nitrogen, and carbon dioxide concentrations along these devices and relative to tissue-health, these parameters can be created using a microfluidic device, whereas with traditional 1- or 2-dimensional cell culture assays these conditions cannot be created. These changes in gas composition (including hypoxic conditions) are critical to the amplification of the specified gene products and corresponding cell behavior.