Sickle Cell Disease, Hemechip

Sickle cell disease (SCD) is a group of inherited disorders of haemoglobin (Hb) synthesis, first described in the medical literature by James Herrick in 1910. Each year about 300,000 infants are born with SCD, including more than 200,000 cases in subSaharan Africa alone. In Nigeria alone, there are over 150,000 of these children born annually and it is estimated that between 50-90% of these children die before their fifth birthday. Overall, in the region, 6% of all childhood mortality in children less than 5 years of age is due to SCD complications and infections. Vaso occlusive crisis and anemia are serious complications of SCD, with infection often being the major cause of hospitalizations, crisis and death. SCD is caused by a point mutation in the sixth codon of the beta globin chain that produces normal Hb (HbA). This substitution of hydrophilic glutamic acid with hydrophobic valine produces sickle Hb (HbS), which is abnormally polymerized at low oxygen conditions causing sickling. Abnormal polymerization of HbS affects red cell membrane properties, shape, and density, and subsequent critical changes in inflammatory cell and endothelial cell function.

The clinical consequences of SCD include painful crises, widespread organ damage, and early mortality. Current standard practices for diagnosing SCD are high performance liquid chromatography (HPLC) and bench-top Hb electrophoresis. These two approaches, however, require trained personnel and state-of-the-art facilities, both of which may be lacking in many parts of sub-Saharan Africa where the disease is most prevalent.

These laboratory methods also carry significant costs which may be unaffordable for most patients. HemeChip diagnostic system offers an original and innovative solution, leveraging a novel engineering approach, to point of care (POC) diagnosis of SCD. HemeChip separates haemoglobin protein types in a miniscule volume of blood (1μL) on a piece of cellulose acetate paper that is housed in a micro-engineered chip with a controlled environment and electric field. Differences in Hb mobilities allow separation to occur within the cellulose acetate paper. A micro-engineered design and multiple layer lamination approach are utilized in fabricating the HemeChip. The design allows rapid manual assembly and results are available within a few minutes of performing the test.

HemeChip can also integrate with a mobile user interface (e.g. IPhone, IPod), which shows the test result quantitatively and objectively on the screen. HemeChip can be used by anyone after a short (30 minute) training, eliminating the need for highly skilled personnel.