Multiplex Detection of DNA Sequences Using the Volume-Amplified Magnetic Nanobead Detection Assay

Abstract

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.

Magnetic sensing technology for molecular analyses

“…A widely used detection scheme is based on Brownian relaxation. 82,83 Each MNP in suspension undergoes thermal rotation with a timescale ( τ B ) proportional to the particle’s hydrodynamic volume. Such thermal rotation affects the frequency-dependent magnetic susceptibility ( χ ) of the MNPs; the quadrant component of χ has its peak at the excitation frequency of 1/ τ B .…”

“…Binding of target molecules to MNPs changes the hydrodynamic diameter (and hence τ B ), and induces a shift in the peak position. Magnetic susceptometry has been used to detect soluble proteins, 84 DNA, 82 and bacteria, 85 with signals measured via induction coils or SQUID. Recently, Park et al demonstrated a compact susceptometer for Brownian relaxation measurement (Fig.…”

Carbon Nanomaterials in Biosensors: Should You Use Nanotubes or Graphene?

“…[15] More specific challenges include: making biosensors compatible with biological matrices, so that they can be used in complex biological samples or even in vivo; [16,17] fabrication of viable biosensors that can operate within confined environments such as inside cells; [17] and multiplexing biosensors so multiple analytes can be detected on one device. [18][19][20] Various kinds of zero-, one-, two-, and threedimensional nanomaterials are helping to meet these challenges. Examples of such materials include semiconductor quantum dots, [21] metallic nanoparticles, [22] metallic or semiconductor nanowires, [14,23] CNTs, [24,25] nanostructured conductive polymers or nanocomposites thereof, [26] mesoporous materials, [27] and various other nanomaterials.…”

Quantification of rolling circle amplified DNA using magnetic nanobeads and a Blu-ray optical pick-up unit

“…In this work, we focus on a sophisticated and sensitive method that exploits the change of the Brownian rotation dynamics of magnetic nanobeads (MNBs) when these attach to DNA coils (Strömberg et al, 2009;Strömberg et al, 2008aStrömberg et al, , 2008b. Using measurements of the magnetic susceptibility of a suspension of MNBs mixed with the sample containing DNA coils, sensitivities in the pM range have been demonstrated.…”