US 12,228,493 B2
Microfluidic impedance cytometry apparatus
Usama Ahmed Abbasi, Bengaluru (IN); Nitin C M, Bangalore North (IN); Sushant Kumar, Bangalore North (IN); and Prakhar Jain, Bhilai (IN)
Assigned to MICROX LABS INC., Wilmington, DE (US)
Filed by Pratimesh Labs Pvt. Ltd., New Delhi (IN)
Filed on Oct. 11, 2022, as Appl. No. 17/963,386.
Claims priority of application No. 202211026597 (IN), filed on May 8, 2022.
Prior Publication US 2023/0358663 A1, Nov. 9, 2023
Int. Cl. G01N 15/10 (2024.01); G01N 15/1031 (2024.01)
CPC G01N 15/1031 (2013.01) [G01N 2015/1006 (2013.01); G01N 2015/1029 (2024.01)] 19 Claims
OG exemplary drawing
 
1. A microfluidic impedance cytometry apparatus, for position determination and impedance measurement of particle/s in a fluid carrying particles, said apparatus comprising:
a microfluidic impedance flow channel for allowing flow of said fluid;
an upstream section configured to channel fluid in a pre-defined direction;
a downstream section configured to channel fluid in a pre-defined direction;
a sensing region configured to receive said channeled fluid, between said upstream section and said downstream section, configured to sense one or more parameters of said fluid, said sensing region comprising one or more sets of pairs of electrodes, each pair forming a current path from an operative top to an operative bottom, each of said pairs being formed by an operative top electrode and an operative bottom electrode, electric potential being applied on said operative top electrode/s, each electrode for a particular pair being parallel-aligned and being symmetric, with respect to each other, same positive electric potential being applied on each of said top electrodes and each of said bottom electrodes is virtually grounded, for a pair;
wherein, edge to edge spacing of adjacent electrode/s is at least 0.5 times of said electrode width but maximum spacing is 5 times of said electrode width;
wherein, width of said channel is at least 1.5 times greater than its height;
a configuration of amplifiers, wherein:
a first summing amplifier configured to add values of current flowing from bottom first electrode and bottom second electrode to obtain a first summation value;
a second summing amplifier configured to add values of current flowing from bottom third electrode and bottom fourth electrode to obtain a second summation value;
a first differential amplifier configured to obtain a first difference value, comprising at least three local maxima and three local minima, over a defined time duration, using said first summation value and said second summation value;
change in current, between electrodes, being a function of position of particle in a vertical direction (Z-direction) and volume of said particle, in said fluid, causing said change in current when said fluid comprising particles pass through said at least a pair of electrodes of said sensing electrodes; and
velocity of the particle being a function of position of particle in a width direction (Y-direction) and in a vertical direction (Z-direction) for a given applied pressure of said fluid.