To test the programmable gelation coupled with a separation process we mixed 30 % Pluronic hydrogel monomers and DNA oligonucleotides (8mer – red labelled and 30mer – green labelled) in His-buffer (50 mM, pH 8) and filled the microfluidic structure with this mixture at 10°C. Then we stopped the flow and the chip was heated up to 60°C, where the Pluronic forms a gel. At this stage of the measurement both DNA oligonucleotides are still complete mixed within the microchannel and showing a green/yellow colour (picture A of the movie sequence in the left figure).
To start the separation process the electrodes were turned on and both DNA strands began to migrate correspondingly to the charged electrodes and were separated over the time triggered by the different movement velocities. The short oligomer moves faster in the gel than the longer one. In the vicinity of the electrodes the velocity of the movement of the DNAs slows down. The values of movement velocity are 87 µm/s (30mer DNA) and 340 µm/s (8mer DNA). This is in good agreement with previous results from CGE experiments using conventional silica capillaries filled with Pluronic hydrogels.
These new results about thermal gelation and separation and compartmentation opens up a wide field of new possibilities in connection with the new high density electronic layer design of the ChµP.