Abstract
This work proposes using a periodic and reversible DEP (dielectrophoresis) field to improve the immuno-capture efficiency of the rare specific cells in a mixed cell suspension. The forward DEP field gently guides all the cells to interact with the bioprobes that are immobilized on a PVDF substrate in the reactor, and the reverse DEP field redistributes the un-bonded cells into the suspension for next reaction chance. The fluorescence visibility of the specific T-cells was also improved via quantum dots/tetramer complex staining. Accordingly, the specifically stained and captured cells could be imaged and counted. The experimental results indicated that the forward DEP can double the cell-capture efficiency compared with that without DEP enhancement, and the reversible DEP scheme can improve the efficiency about 25% further. This assay is also successively used to detect the population of rare cytotoxic Tc cells in a human blood sample; and the Tc cell has specific receptors on the membrane surface to identify the Epstein-Barr virus (EBV). © 2010 Elsevier B.V. All rights reserved.