Whole Blood CD4 Cell Counting

Whole blood passively flowing into low cost laminated fluidic cartridge for CD4 cell counting.

18 Surface Modification for Blood Flow.j

The Application

A client created a new technology to measure CD4 cell count in whole blood for HIV treatment in the developing world. The product required a low cost, disposable fluidic cartridge integrated with the optical imaging technology for detection.

The Challenge

The cartridge required the passive flow of whole blood into a reaction chamber, uniform mixing with fluorescence tagged reagents, continuing to a detection chamber with an optical window.  Consumable requirements include:

  • Low cost of less than a dollar

  • High precision flow cell

  • Passive mixing of dry reagents

  • Uniform dispersion of reagents in imaging channel

The Solution

Wainamics used laser cutting and plastic-PSA lamination for rapid prototyping, allowing whole blood assay testing within two weeks into the project. Uniform capillary force driven flow and passive reagent mixing was achieved through surface modification, formulation adjustments and use of specialty porous materials. Design was then transferred to high volume manufacturing using injection molding.

The Result

Rapid prototyping enabled simultaneous assay testing and cartridge development. The product was successfully launched in 2014.