Microscopic mechanisms influencing the volume amplified magnetic nanobead detection assay

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

“…At higher MNB concentration, a larger amount of MNBs bind to DNA coils during incubation. Conversely, a high MNB concentration might limit the sensitivity to higher c coil (Strömberg et al, 2008a(Strömberg et al, , 2008b.…”

“…At high target concentrations, the dynamic rotation of the DNA coil-MNB cluster also appears, but at much lower frequency (few Hz) due to the high hydrodynamic volume of the complexes (Zardán Gomez de la Torre et al, 2011;Strömberg et al, 2008aStrömberg et al, , 2008b.…”

“…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.…”

On‐Chip Detection of Rolling Circle Amplified DNA Molecules from Bacillus Globigii Spores and Vibrio Cholerae

“…[ 10 ] Strömberg et al [ 11 ] demonstrated the use of a Brownian relaxation detection scheme for the detection of RCA coils down to pM concentrations as magnetic nanobeads bound to micrometer-sized coils show a substantially different Brownian relaxation than free magnetic nanobeads. [11][12][13][14] The Brownian relaxation response was characterized via measurements of the frequency spectrum of the complex magnetic susceptibility ( χ ) using a superconducting quantum interference device (SQUID) magnetometer. However, a SQUID magnetometer is a bulky instrument that requires cryogenic liquids, which makes it unsuitable for the readout in a lab-on-a-chip biosensor.…”

Evaluation of the Sulfo-Succinimidyl-4-(<I>N</I>-Maleimidomethyl) Cyclohexane-1-Carboxylate Coupling Chemistry for Attachment of Oligonucleotides to Magnetic Nanobeads

“…[17][18][19][20] In the present work, the sulfo-SMCC coupling chemistry was introduced for the immobilization of oligonucleotides onto dextran-coated amine-functionalized [21][22][23] to the oligonucleotide-functionalized magnetic bead was also evaluated since the intended use of the functionalized beads is in biosensor applications of the type presented earlier. 6 Table I for details about the oligonucleotide sequences used. The TCEP-reduction of the thiolated oligonucleotides was performed as follows: A mixture consisting of 50 mM TCEP (pH 7.5), 10 mM EDTA and thiolated oligonucleotides was prepared and incubated in a water bath at 37 C for 1 h. The mixture was spun (1 min at 3000 rpm) one time through a MicroSpin G50-column (GE Healthcare) in order to remove TCEP excess.…”