Profiling metabolites provides essential information about cellular growth, development, and communication within complex biological systems. The analysis of these molecules is challenging due to both their variety and to the dynamic spatial and temporal changes in that occur in living systems. Nuclear magnetic resonance (NMR), vibrational spectroscopy, and mass spectroscopy (MS) have been utilized to profile the breadth of metabolites produced in different cellular systems. These techniques are often destructive and lack the spatial and temporal resolution needed to analyze metabolites over time. Labeling and imaging techniques that use phenomena such as Forster resonance energy transfer (FRET) based sensors, Raman and MS based imaging have been reported to achieve time dependent measurements. However, these techniques can be limited in their ability to analyze more than a few metabolites at a time, in the case of FRET, or require performance under vacuum or advanced surface modification strategies.<br/>Here, we present the integration of a nano-fluidic interface with a microfluidic network to sample from locations within a model sample environment. This platform enables non-destructive sampling of living systems at time scales necessary to correlate evolving metabolite profiles with changes in system architecture. A polyester tracked etched (PETE) membrane was integrated between a microfluidic network and a model environment.  Molecules diffusing across the membrane from a region of interest were imaged and collected within the sampling channel for analysis. Sampling regions were defined by integrating a ~6µm thin porous polydimethylsiloxane (PDMS) membrane between the sampling channel and the PETE membrane. Three different sample aperture sizes (25, 50 and 100µm) were chosen to understand the sampling dynamics through the nanofluidic interface. As a proof of principle, the platform was characterized using fluorescein isothiocyanate (FITC) and green fluorescent protein (GFP) to evaluate the diffusional flux that can be collected with minimum perturbation to the system.<br/>

Nanofluidic interfaces for time resolved imaging of cellular metabolites

255th National Meeting (2018)

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