Gap-varying, lifted hele-shaw cell (lhsc) for controlled liquid film flow and devices containing the same

A suspension micro-filtration device based on the gap-varying LHSC, characterized in that the said device comprises of

• a. top plate comprising spherical cap (1),
• b. a flat bottom plate (3) comprising of:
• i. a circular groove (41) with two extending arms, acting as a barrier to constrain liquid extracted from the suspension,
• ii. a microchannel (42) that pulls and collects the liquid,
• iii. a thin polymer disc (43) attached to the surface at the centre of the groove,
• iv. a circular filter membrane (44) assembled over the disc (43) where edge of the membrane is secured on the bottom plate using tape (47) on three corners and a polymer laminate (45) on the fourth corner, wherein the disc (43) raises the membrane at its centre and creates a radially-symmetric wedge-shaped space between the membrane and bottom surface, and;
• c. a circular liquid film (48) between the two plates.

A method of filtration based on the gap varying LHSC comprising the steps of:

• i. placing suspension droplet at the central disc (43);
• ii. squeezing the suspension against the filter membrane (44) by bringing top plate with spherical cap (1) and flat bottom plate (3) together;
• iii. separating the top and bottom plates (1, 3) to an extent to break the liquid bridge (46) to move the filtrate radially outward from the central region to microchannel mouth (49) and fill the microchannel (50);
• iv. draining the filtrate in the microchannel (42) through outlet (51) with micro-pipette or tubing attached to suction pump to collect the filtrate.

A hand operated filtration device comprising

• polymer bellow (61);
• motion-limiting stop (62),
• vent valve-closed (63);
• push plate (64);
• release plate (65);
• vent valve-open (66), and
• gap-varying lifted Hele-Shaw cell (LHSC) with radial flow of a circular liquid film comprising:
• i. top plate with spherical cap (1);
• ii. flat bottom plate (3);
• and
• iii. circular liquid film (2) in between the said two plates.

A device for batch processing of blood sample for large-scale plasma separation comprising:

• reservoir (71);
• flushing liquid reservoir (72) and input control valve (73) and
• sphere-on flat lifted Hele-Shaw cell (LHSC) with radial flow of a circular liquid film comprising:
• i. top plate with spherical cap (1);
• ii. flat bottom plate (3);
• and
• iii. circular liquid film (2) in between the said two plates.