The CFM Printhead
Tip of the CFM Printhead
The CFM Printhead
The 48 Spot CFM Printhead uses a network of microchannels to deposit 48 samples at one time in a 4 x 12 block. The spots are 400 x 600 microns with a pitch of 875 microns. For custom sensing applications array design and layout can be engineered to meet specific geometry requirements. Contact us for more details.
The printhead’s microchannels are integrated within a soft silicone molded device. The printhead is operated by pressing the silicone tip against a smooth surface to form a seal around the spot deposition chambers. Samples are loaded into the CFM Instrument using standard microtiter plates. The automated sample handing transfers the samples into the microfluidic printhead using microbore tubing. The samples are then passed through the CFM microchannels over the slide surface and cycled back and forth until the desired deposition level is achieved.
Superior Printing Results
CFM technology enables printing at sample concentrations down to 10 - 100 ng/mL, while other technologies require 10 - 250 ug/mL to achieve similar levels of biomolecule deposition. CFM printing also improves spot morphology, enables printing from crude media, and prevents biomolecule denaturation.
The image at the right compares the spot quality of Protein A deposited on a gold Surface Plasmon Resonance (SPR) surface using the CFM and a conventional pin printer. Twelve concentrations of Protein A, from a high concentration of 250 μg/ml down to a low concentration of 0.12 μg/mL, were printed in quadruplicate.
The pin-printed spots show poor spot morphologies with clear nonuniformity when protein was pin printed at lower concentrations and significant spreading at higher concentrations. In contrast, the spots created with the CFM system appear uniform throughout the spot area even at low protein concentrations and show no evidence of spreading or “comet tailing” even at the highest protein concentrations. As an added benefit, the CFM technology allows a wash step to be performed while the printhead is still in place, enabling the removal of any unadsorbed protein. Thus, the CFM outperforms competing technologies across a wide rage of sample concentrations.
The binding data from these two arrays further demonstrates the benefits of CFM printing, especially at low sample concentrations. IgG was passed across the arrays and binding was observed using a SPR imaging device. The figure below displays the maximum binding signal for the IgG binding to the prined protein A spots. The CFM fluidic spotter allows the detection of samples down to a printed protein A concentration of 0.1 µg /mL, while the pin spotter loses signal around 10 µg /mL. 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.
