Microfluidics are generally closed systems inside which samples must pass and to which user-to-chip interfaces must be established. We have developed a microfluidic probe (MFP) that overcomes the usual limitations of microfluidics by combining the concepts of microfluidics and of scanning probes.
With this approach, liquid boundaries formed by leveraging hydrodynamic forces underneath the MFP confine a flow of processing solution replacing the solid walls of closed microchannels. The MFP is therefore mobile and can be used to process large surfaces and objects by scanning across them. In addition, it can process biological samples that cannot be placed within closed microfluidic systems.
MFPs are versatile as they can microarray proteins on surfaces, form chemical gradients on surfaces, effect multiphase laminar flow patterning, "erase" patterns from a surface, localize staining of adherent cells, and address single living cells on a surface.
We recently showed that tumor markers can be detected in tissue sections with high spatial resolution. Three videos show, respectively, the confined flow between two apertures of an MFP, an MFP microarraying proteins on a surface, and an MFP removing proteins from a surface.
We are now extending several concepts related to the MFP with partners, including the Institute of Clinical Pathology of the University Hospital of Zurich. This work will be supported in part by a SystemsX.ch project entitled µFluidX.
Part of this work is done in the framework of the EU-funded project BioProbe.