Multiplex detection of DNA sequences using the volume-amplified magnetic nanobead detection assay

The possibility for conducting multiplex detection of DNA-sequences using the volume-amplified magnetic nanobead detection assay [Stromberg, M.; Goransson, J.; Gunnarsson, K.; Nilsson, M.; Svedlindh, P. and Strømme, M. Nano Lett. 2008 , 8, 816-821] was investigated. In this methodology, a batch consisting of a mixture of several sizes of probe-tagged magnetic beads was used for detection of several types of targets in the same compartment. Furthermore, a nonlinear least-squares deconvolution procedure of the composite imaginary part of complex magnetization vs frequency spectra based on the Cole-Cole model was applied to analyze the data. The results of a quantitative biplex analysis experiment were compared with the corresponding separate single-target assays. Finally, triplex analysis was briefly demonstrated qualitatively. Biplex and triplex detection were found to perform well qualitatively. Biplex detection was found to enable a rough target quantification. Multiplex detection may become a complement to performing multiple separate single-target assays for, e.g., parallel detection of multiple infectious pathogens. Multiplex detection also permits robust relative quantification and inclusion of an internal control to improve quantification accuracy.