Separation of simulants of biological warfare agents from blood by a miniaturized dielectrophoresis device

Separation of simulants of biological warfare agents from blood using dielectrophoresis (DEP) was demonstrated in a miniaturized DEP device. The device was fabricated by laminating five different layers (all 40 mm x 40 mm) including a polycarbonate substrate, a pressure sensitive acrylic adhesive (PSA) layer, a patterned polyimide layer with a flip-chip bonded dielectrophoresis chip (DEP chip), a PSA layer with microfluidic channel, and a glass cover plate. The DEP chip consisted of repetitive interdigitated electrodes with characteristic dimension of 50 pm. This device was employed to separate different simulants of biological warfare agents (BWA), namely Bacillus cereus (B. cereus), Escherichia coli (E. coli) and Listeria monocytogenes (L. monocytogenes), from blood, individually or simultaneously. PCR amplification, which was inhibited by blood components in pre-separation samples, successfully revealed bands in post-separation samples containing single or multiple BWA. Up to 97% efficiency of separation was achieved as demonstrated by culturing post-separation E. coli cells. The DEP device described here can potentially be used to reduce sample complexity for detection of infectious disease pathogens and biological warfare agents.