Integrated and standalone label and reagent-free microfluidic devices and microsystems for differential white blood cell counts

Abstract

A method of establishing a differential white blood cell count includes directing at least one stream of deionized water into a microfluidic device containing a sample of whole blood or a cell-rich fraction to generate a lysate stream of intact white blood cells; directing at least one stream of deionized water into the lysate stream to form a virtual non-conductive aperture in a channel of the device; and performing impedance cytometry of the lysate stream via coplanar electrodes to detect the presence of intact white blood cells. A microfluidic device includes a blood separation section. An analyte sensor detects electrical changes in a cell-free fraction. Lysate from a cell-rich fraction is analyzed to detect circulating tumor cells or white blood cells including neutrophils, lymphocytes, monocytes, eosinophils, and basophils. A method of fabricating and a standalone cell-rich microfluidic device are disclosed for differential white blood cell counts.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of, and priority to, a PCT application, filed on Nov. 17, 2014, entitled “INTEGRATED AND STANDALONE LABEL AND REAGENT-FREE MICROFLUIDIC DEVICES AND MICROSYSTEMS FOR DIFFERENTIAL WHITE BLOOD CELL COUNTS” by Hadar Ben-Yoav et al., which claims priority to U.S. Provisional Patent Application No. 61 / 905,028, filed on Nov. 15, 2013, entitled “SYSTEM AND METHOD FOR MONITORING DRUG TREATMENT” by Hadar Ben-Yoav et al.; the entire contents of both applications are incorporated by reference herein. These applications relate to U.S. patent application Ser. No. 14 / 274,643, filed on May 9, 2014, entitled “ANALYTICAL MICRO-DEVICES FOR MENTAL HEALTH TREATMENT MONITORING” by Hadar Ben-Yoav et al., the entire contents of which are incorporated by reference herein. U.S. patent application Ser. No. 14 / 274,643 claims priority to U.S. Provisional Patent Application No. 61 / 905,028 and U.S. Provisional Patent Application No. ...

AI Technical Summary

Benefits of technology

The present patent introduces a point of care testing (POCT) device that addresses practical limitations in terms of size and scale-up. It integrates pure water hydrodynamic focusing and pure water erythrocyte lysis to improve the signal-to-noise ratio and eliminate background signals while enhancing white blood cell differentiation. The device employs a two-layer design with low-cost fabrication using polydimethylsiloxane (PDMS) channels and coplanar gold electrodes on glass.

Problems solved by technology

These factors are some of the major barriers in bringing this technology to the point of care (POC), where it would benefit patients as well as physicians by providing immediate results and increasing accessibility, especially in remote locations [2].

However, these devices all rely on chemical reagents to enhance differentiation, and to date no portable POC device achieves a full (five-part) white blood cell differential.

The former's approach, however, is limited due to inclusion also of optical measurements (and thus requiring fluorescent labels and external lasers, lenses, etc.), chemical reagents to enhance white blood cell differentiation, and an exceedingly complex fabrication method.

The latter forgo optical measurements, but still rely on chemical reagents and suffer from inadequate differentiation.

A notable limitation is the reliance on chemicals to achieve erythrocyte lysis and sufficient cell type differentiation (saponin and formic acid, followed by sodium carbonate after a set exposure time).

However, current implementations still suffer from limited resolution, and employ multi-layer fabrication processes.

While flow focusing has been utilized to enhance the performance of coulter counter-type devices, to date no systematic study has been conducted on the interplay between flow ratios, particle sizing sensitivity, and throughput [6].

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