A sheath-less combined optical and impedance micro-cytometer.

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Cell Biology

Background:

• Classical cytometers are essential for cell analysis but are often large, complex, and expensive.
• There is a need for miniaturized, portable, and cost-effective cell analysis platforms.

Purpose of the Study:

• To develop and validate a sheath-less micro-cytometer capable of measuring multiple cellular parameters.
• To demonstrate the utility of this micro-cytometer for analyzing human blood and enumerating CD4+ T-cells.

Main Methods:

• The micro-cytometer integrates fluorescence, large angle side scatter, and dual-frequency electrical impedance (volume and opacity) measurements.
• Benchmarking was performed using size and fluorescent bead standards.
• The device was evaluated by analyzing human blood samples.

Main Results:

• The micro-cytometer demonstrated excellent size accuracy (CVs ≤ 2.1%), sensitivity, and a dynamic range of 3.5 orders of magnitude.
• Accurate CD4+ T-cell enumeration was achieved using a four-part differential leukocyte assay.
• The platform operates at sample flow rates of 80 μL per minute.

Conclusions:

• The integrated sheath-less micro-cytometer offers the core information content of classical cytometers in a compact, simple, portable, and low-cost format.
• This technology has potential for widespread application in cell analysis and diagnostics, particularly in resource-limited settings.