SUNConferences, 17th Annual Conference of the Rapid Product Development Association of South Africa

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RAPID PROTOTYPING OF CENTRIFUGAL MICROFLUIDIC MODULES FOR POINT-OF-CARE BLOOD TESTING
Phophi Madzivhandila, Suzanne Smith, Michael Wiederoder, Pieter Roux, Kevin Land

Last modified: 2016-10-03

Abstract


We present modular centrifugal microfluidic devices that enable a series of blood tests to be performed, resulting in a full blood count (FBC). CD-based microfluidics control fluids on devices shaped like compact discs by rotation, using a small motor to generate a centrifugal force [1]. The modular approach allows for rapid prototyping of device components in a generic format to complete different combinations of blood tests with quick turn-around times usingĀ  low-cost and rapid manufacturing processes. Individual modular devices are then analyzed by a separate optical or microscopy imaging system and disposed thereafter, while the disc control platform can be re-used. This work presents application examples for blood smear tests and packed cell volume (PCV). PCV is one of the blood count parameters of a FBC test, also known as a haematocrit [2].

FBC tests are commonly performed as a starting point in evaluating patients with various medical conditions such as anemia and polycythaemia [2]. If abnormal results have been found in a FBC, peripheral blood smear analysis is then used as an important diagnostic test [3]. Centrifugal system capabilities are useful for blood tests such as blood cell separation [4]. The CD platform shows promise as a microfluidic technology for diagnostic tests at the point-of-care, such as at rural clinics found across South Africa [5].

The re-usable CD and disposable modular components are manufactured from transparent layers of polycarbonate (PC), polymethyl methacrylate (PMMA) and pressure sensitive adhesive using a laser cutter, milling machine and manual press. This makes the modular blood slides robust and low-cost compared with traditional glass slides used by pathologists to create blood smears.

The results show that high quality blood smears can be generated repeatably and compare well to manual smears when inspected by microscopy. PCV results are comparable to those obtained from FBC tests performed at pathologist laboratories using automated, standard techniques.

The platform can be extended to investigate other blood analysis techniques such as density gradient tests. Additive manufacturing techniques could be applied to realize the modular components and CD devices. The modular centrifugal microfluidic approach has the potential to have great impact on the lives of South Africans by providing rapid blood testing at the point-of-care.


Keywords


modular, centrifugal microfluidics, prototyping