A microhole chip allows single cells to be picked out of the blood sample, placed on separate holes in the substrate for analysis, and removed individually afterwards. A slight underpressure is applied to the cells that holds each one in its allotted place by suction.

The new microhole chip can be populated with 200,000 single cells, each held in place in separate holes.
(Credit: Fraunhofer IBMT)

In a collaborative research project concerning the identification of circulating tumor cells, a two-step cell analysis method was applied. In the first step, suspicious-looking cells were selected using a microscope. In the second step, the selected cells underwent detailed analysis using the more time-intensive method of Raman spectroscopy.

Another advantage of the new microhole chip is that it can be populated with 200,000 cells, each one in a separate hole, in a matter of minutes. A micropipette is used to remove individual tumor cells from the chip for further analysis. The level of underpressure chosen to hold them in place is too low to cause any damage.

The new chip has other possible applications, including as a selection system for protein-producing cells. Microchips with well-defined micropores can be used as a substrate for in-vitro modeling of physiological barriers such as the blood-brain barrier or the intestinal barrier.