Nip the bubble in the bud_ a guide to avoid gas nucleation in microfluidics_edited_edited.

Open Space Microfluidics

Hovering Microfluidic Devices

Microfluidic devices often operate on biological samples by dissociating them prior to bringing them into a chip (sample-to-device) with an integration of a read-out (for e.g., imaging, collection, isolation). This approach is at odds with studies that investigate how entities within a sample interact in space (ligands bound to patterned surfaces, cell co-cultures or tissues from biopsies). Our group developed a scanning probe technology, the vertical Microfluidic Probe (MFP), that brings microfluidics to an open and aqueously immersed surface. This technology can process samples in their standard life-science friendly formats, thus enabling the conversion of any biochemical or molecular biology assay into a spatial one.

Hydrodynamic Flow Confinement

The underlying fluidic principle of the MFP is the hydrodynamic flow confinement (HFC), where an asymmetric flow field on an immersed surface allows for the shaping and confining of the injected liquid on top. Thus nanoliter volumes of chemicals can be spatially confined at the μm-length scale, without the probe in mechanical contact with the sample. HFCs are implemented using microfabricated or 3D printed MFP heads, with capillaries ending at the head apex that hovers 20 - 100 µm above the surface to be processed. Nesting such confined laminar flows within and next to each other, allows for a range of surface assays to be run in sequence and in parallel, with appropriate laminar shielding of the rest of the unprocessed surface.

HFC_Topography_Oskooei_1_DarkMode-24_edi

From G. Kaigala, R. Lovchik, U. Drechsler, E. Delamarche, Langmuir, 2011, 2, 5686–5693.

From J. Autebert, A. Kashyap, R. D. Lovchik, E. Delamarche and G. V. Kaigala, Langmuir, 2014, 30, 3640-3645.

From A. Oskooei and G. Kaigala, IEEE Biomedical Engineering, 2016,

10.1109/TBME.2016.2597297

Current Projects

Rapid Prototyping of New MFP Probes

Using DLP 3D printing, we are designing a new class of MFP heads which were limited prior to planar designs owing to DRIE based clean room microfabrication techniques. The 3D printing solution allows us to embed more complex microfluidic routing and thus new functions within the MFP devices.

Integrating Segmented (multi-phase) Flows

For integration with single cell workflows, we are developing a new class of MFPs for water-in-oil compartmentalization allowing for lower dispersion of bioanalytes, which is a critical requirement to reduce cross contamination between material capture using the MFP.

Endoscopic HFCs

In this project, we are designing a class of hand-held MFP devices for the purpose of integrating within existing endoscopic instruments (gastroscopes), with an integrating distance sensing mechanism and the ability to rotate within luminal surfaces.