Patent ID: 11883823
Assignee: THE GOVERNING COUNCIL OF THE UNIVERSITY OF TORONTO
Field: Measurement (Instruments)
Classification: CPC B  G | IPC B  G

Claim 8:
9. A digital microfluidics based method for filtration of heterogeneous suspensions, comprising:
a) positioning a porous material between a bottom plate and a top plate in a digital microfluidic device, the porous material having a pre-selected porosity to prevent particles larger than a pre-selected size to pass through while allowing passage therethrough of particles being smaller than said pre-selected size, the porous material having a loading section that extends beyond an edge of the top plate;
b) dispensing a sample droplet containing particles of different sizes onto the loading section of the porous material such that the sample droplet is wicked into the porous material;
c) dispensing a reagent onto an electrode array located on the bottom plate and actuating the electrode array in such a way as to drive the droplet through the porous material from a first side to a second side of the porous material such that the particles smaller than the pre-selected size pass out of the porous material to give a particle loaded reagent droplet with the smaller particles on the second side while the particles larger than the pre-selected size remain trapped in the porous material; and
c) actuating the electrode array for displacing the particle loaded reagent droplet away from the porous material to await further processing,
wherein the porous material is an elongated strip of porous material having a length defined by elongated opposed sides and opposed ends, and
wherein the method comprises preventing liquid exiting an end of the porous strip opposite the loading section by providing said end of the porous strip opposite the loading section with a non-porous hydrophobic material embedded therein, and the elongated opposed sides being devoid of the non-porous hydrophobic material,
wherein the non-porous hydrophobic material has hydrophobicity higher than that of said porous material, and the non-porous hydrophobic material is anchoring the strip of porous material to the top and/or bottom plate.