Wells for optimized sample loading in microfluidic chips
The present invention relates to a loading well ( 320 ) comprising a lateral wall part ( 3211 ) in cross-section parallel to the base plan (x/y) and/or a bottom wall part comprising at least one sloped bottom section ( 32121 ). The present invention also relates to a microfluidic chip comprising the same: systems comprising the same configured to reduce the dead volume of a drop of sample to be loaded in the microfluidic chip and/or to trap a drop in a defined location; and methods using the same.
1 . A well ( 320 ) for loading a sample into a microfluidic chip, the well comprising a loading opening ( 325 ) having an open cavity ( 324 ),
wherein the well prior to loading of said sample is at least partially filled with an oil continuous phase ( 312 ),
wherein the well is bounded by a wall ( 321 ) which comprises a bottom wall part ( 3212 ) globally extending according to a bottom plane (wbp) parallel to the base plane (x/y) and a lateral wall part ( 3211 ) extending along a well lateral direction (wld) disposed according to an angle 0°<α<180° relative to the bottom plane (wbp),
wherein the loading opening ( 325 ) is defined by a free end of the lateral wall part ( 3211 ) opposite to the bottom plane (wbp),
wherein the bottom wall part ( 3212 ) comprises at least one sloped bottom section ( 32121 ), which has a main slope with an average sloping angle δ from about 5° to about 15° from the bottom plane (wbp) at the level of the lateral wall part ( 3211 ) to a position of higher depth d of the sloped bottom section ( 32121 ), and
wherein an inlet port ( 330 ) is accommodated in the bottom wall part ( 3212 ), located off-center in the bottom wall part ( 3212 ) and at the position of higher depth d of the sloped bottom section ( 32121 ).
2 . The well ( 320 ) according to claim 1 , wherein the angle α has a value ranging from about 80° to about 105° relative to the bottom plane (wbp).
3 . The well ( 320 ) according to claim 1 , wherein the oil continuous phase has a relative density greater than 1.01.
4 . The well ( 320 ) according to claim 1 , wherein the inlet port ( 330 ) is located at a distance d inlet-wall in the base plane (x/y) from a curved section of the lateral wall part ( 3211 ) ranging from about 0.5 mm to about 2.5 mm.
5 . The well ( 320 ) according to claim 4 , wherein the curved section of the lateral wall part ( 3211 ) has a curvature radius ranging from about 0.5 mm to about 2.5 mm.
6 . A microfluidic chip ( 300 ) comprising the well ( 320 ) according to claim 1 .
7 . The microfluidic chip ( 300 ) according to claim 6 , further comprising a microfluidic network which is partially or completely filled with the oil continuous phase ( 312 ).
8 . A system for reducing the dead volume of a drop of sample ( 313 ) to be loaded in a microfluidic chip ( 300 ), the system comprising a Polymerase Chain Reaction (PCR) instrument and the microfluidic chip ( 300 ) according to claim 6 .
9 . The well ( 320 ) according to claim 1 , wherein the oil continuous phase has a relative density greater than 1.05.
10 . The well ( 320 ) according to claim 1 , wherein the oil continuous phase has a relative density greater than 1.1.
11 . The well ( 320 ) according to claim 1 , wherein the oil continuous phase has a relative density greater than 1.5.
12 . The well ( 320 ) according to claim 4 , wherein the curved section of the lateral wall part ( 3211 ) has a curvature radius of about d inlet-wall .
13 . A method for generating a population of droplets of a sample, the method comprising in succession:
providing the microfluidic chip ( 300 ) according to claim 6 ,
loading a sample into the well ( 320 ) of said microfluidic chip ( 300 ), and
passing the sample through a droplet generator ( 340 ).
14 . The well ( 320 ) according to claim 1 , wherein the sample is an aqueous sample.