Microplate washing: process description and improvements.
Heterogeneous immunoassays require wash steps in order to separate bound from free constituents. In this paper we demonstrate that in microplate assays the washing process includes two separate physical processes: (1) a rapid and wash volume-dependent direct dilution of the droplet-shaped residual volume, and (2) a diffusion-limited and strongly time-dependent dilution of a residual layer of liquid, which necessitates the use of time-consuming soak times in the immunoassay. We have shown that optimizing the motion of the wash fluid effectively reduces the residual layer thickness that results in extended soak times. This results not only in improved washing efficiency and reduced background variance in the immunoassay, it also yields a significantly improved immunoassay sensitivity.
Beumer
T
T
Methodology Research Unit, Organon Teknika BV, Boxtel, Netherlands.
Stoffelen
E
E
Smits
J
J
Carpay
W
W
D007118:Immunoassay / Q000379:methods*; D013997:Time Factors