The CFM Instrument
The CFM instrument uses built-in sensors and pumps to control the flow within the CFM print head.  To operate the instrument, a print head is mounted horizontally on a fixed deck.  A slide is mounted vertically on a movable stage, then brought into contact with the print head tip to form a seal.  Programmable flow profiles are used to cycle the samples across the surface at defined flow rates for a given period of time, depositing the materials in solution onto the slide with enhanced uniformity and sensitivity.  After deposition, the slide can be moved and the printing process repeated.

 
 
In contrast to other arraying instruments which use pins or non-contact technologies to deposit droplets on a surface, the CFM’s unique flow approach gives researchers greater control over the deposition process.  This allows for enhanced signal by capturing more material on the surface, as well as improved spot morphology and uniformity.Using a Surface Plasmon Resonance instrument for detection, the CFM was compared to a commercial pin arrayer by depositing varying concentrations of protein A on a gold SPR substrate and monitoring the real-time binding of IgG to the printed spots. The figure below displays the maximal binding response of Human IgG to the printed spots.  Binding to the pin spotted protein A was undetectable below ~5 µg/mL, while the CFM spots enabled detection down to the lowest concentration in this study.    This is highly significant, because many interesting low expression proteins, which could serve as novel disease biomarkers for early detection of cancer and other diseases, are naturally found in concentrations below 5 µg /mL.
Performance