Fig. 1. HemeChip: paper-based microchip electrophoresis for hemoglobin testing.

HemeChip is a miniaturized, fully integrated cartridge-based microchip electrophoresis system that can be mass-produced. (A) Top (1) and bottom (5) plastic parts are manufactured via injection molding. Cartridge contains a single strip of cellulose acetate paper (2), a pair of blotting pads (3), and integrated stainless-steel electrodes (4). (B) HemeChip cartridge design is compact, fully integrated, and self-contained, including liquid compartments (buffer pools). One corner of the HemeChip cartridge is chamfered to restrict orientation and facilitate correct placement during use. (C) A partial section view of the internal components of HemeChip, showing the cross-section of an electrode and the cellulose acetate paper. (D) A schematic representation of the separation of hemoglobin variants in HemeChip: normal hemoglobin (Hb A), fetal hemoglobin (Hb F), sickle hemoglobin (Hb S), and hemoglobins C/E/A₂ that co-migrate. A blue control marker (xylene cyanol) is pre-mixed with blood before sample application into the cartridge. (E) A fully assembled injection molded HemeChip is shown after a completed test with hemoglobin S and C bands that are visible.