ИСТИНА

We present a magnetic are trying to develop a novel detection and characterization mechanism bioassay based on functionalized magnetic nanoparticles (fMNPs) and high-TC SQUIDs as a magnetic readout. for The overall aim of the work is to develop an ultra-sensitive and portable system for rapid detection of the influenza pandemicsvirus. It is based on of a target DNA sequence using suspended biofunctionlized magnetic nanoparticles (MNP). Theobservation of the change in Brownian relaxation dynamics of the fMNPs suspended in liquid is the base of magnetic sensing for in the presence/absence of the target molecules (DNA) [1]. A specific The relaxation time of the Brownian dynamics of the suspended MNPs is a function of the particle size. Therefore, bbinding of the DNA strand target molecule to the fMNPs results in increase of would change the relaxation time and is an indication of presence/absence of influenza virus and can be detected through, e.g. measurements of imaginary part of AC magnetic susceptibility. To reach required levels of sensitivity of < 1000 The high specificity is secured by tailor made biofunctionlized MNPs which would only attach to influenza RNA strand. target molecules, ultra-sensitive magnetic readout has to be used. A hHigh-Tc TC SQUID (Superconductor Quantum Interference Device) gradiometers is have been previously used for developed for a sensitive AC-susceptometry measurements of fmagnetic nanoparticles (MNPs [2]). It was shown that equivalent iron content sensitivity of the high-TC SQUID readout corresponds to about 107 MNPs. Volume amplification using the padlock-probe-ligation technique [2] and RCA [3] could provide additional gain up to 1000 MNPs per target molecule. Therefore, current level of sensitivity would exceed 104 target molecules. [1] Astalan, A. P. et al, Biosensors and Bioelectronics 19, 945 (2004). [2] Öisjöen, F. et al, Biosensors and Bioelectronics 25 1008 (2010). [3] Nilsson, M. et al., Science 265, 2085 (1994).