Embodiments of the microfluidic device may include of an array of microfluidic cell capture chambers, each functionalized with a different antibody to recognize a target antigen, and a network of code-multiplexed Coulter counters placed at strategic nodes across the device to quantify the fraction of cell population captured in each microfluidic chamber. For example, an apparatus may comprise a fluid inlet port divided into a plurality of separate microfluidic paths, each separate microfluidic path configured to transport a plurality of cells, the plurality of separate microfluidic paths, each comprising a plurality of microfluidic cell capture chambers, an outlet port to discharge a merged output of cells from the plurality of microfluidic cell capture chambers, and a plurality of sensors to detect cells passing into or out of a microfluidic cell capture chamber.

A method of forming a plurality of lipid bilayers over an array of cells in a nanopore based sequencing chip is disclosed. Each of the cells comprises a well. A first salt buffer solution with a first osmolarity is flowed over a cell in the nanopore based sequencing chip to substantially fill a well in the cell with the first salt buffer solution. A lipid and solvent mixture is flowed over the cell to deposit a lipid membrane over the well that encloses the first salt buffer solution in the well. A second salt buffer solution with a second osmolarity is flowed above the well to reduce the thickness of the lipid membrane, wherein the second osmolarity is a lower osmolarity than the first osmolarity such that an osmotic imbalance is created between a first volume inside the well and a second volume outside the well.

Embodiments of the microfluidic device may include of an array of microfluidic cell capture chambers, each functionalized with a different antibody to recognize a target antigen, and a network of code-multiplexed Coulter counters placed at strategic nodes across the device to quantify the fraction of cell population captured in each microfluidic chamber. For example, an apparatus may comprise a fluid inlet port divided into a plurality of separate microfluidic paths, each separate microfluidic path configured to transport a plurality of cells, the plurality of separate microfluidic paths, each comprising a plurality of microfluidic cell capture chambers, an outlet port to discharge a merged output of cells from the plurality of microfluidic cell capture chambers, and a plurality of sensors to detect cells passing into or out of a microfluidic cell capture chamber.

A biological particle counting system can include: an impedance particle counter comprising at least one sample aperture; a pump configured to pull particles through the at least one sample aperture of the impedance particle counter for counting, the pump producing a vacuum pressure; and a stepper motor configured to adjust a speed of the pump to substantially maintain the vacuum pressure.

A method of forming a plurality of lipid bilayers over an array of cells in a nanopore based sequencing chip is disclosed. Each of the cells comprises a well. A first salt buffer solution with a first osmolarity is flowed over a cell in the nanopore based sequencing chip to substantially fill a well in the cell with the first salt buffer solution. A lipid and solvent mixture is flowed over the cell to deposit a lipid membrane over the well that encloses the first salt buffer solution in the well. A second salt buffer solution with a second osmolarity is flowed above the well to reduce the thickness of the lipid membrane, wherein the second osmolarity is a lower osmolarity than the first osmolarity such that an osmotic imbalance is created between a first volume inside the well and a second volume outside the well.