TY - GEN
T1 - Liquid-phase detection of biological targets with magnetic markers and high Tc SQUID
AU - Uchida, S.
AU - Higuchi, Y.
AU - Ueoka, Y.
AU - Yoshida, T.
AU - Enpuku, K.
AU - Adachi, S.
AU - Tanabe, K.
AU - Tsukamoto, A.
PY - 2013/10/15
Y1 - 2013/10/15
N2 - We developed a highly sensitive HTS SQUID system for liquid-phase detection of biological targets using Brownian relaxation of magnetic markers. The SQUID was made of a ramp-edge Josephson junction using RE123-based multilayer process, and it showed a flux noise of 7.5 micro flux-quantam/Hz1/2 in the white noise region. The 1/f noise was 14 micro flux-quantam/Hz1/2 at f = 1 Hz when the SQUID was operated with AC bias mode. Using the SQUID system, we detected a biological target called biotin. In the experiment, biotins were fixed to a large polymer bead with a diameter of 3.3 micron meter. Streptavidin-coated magnetic markers were used for the detection. The bound and unbound (free) markers were magnetically distinguished using the difference in their Brownian relaxation time, i.e., without using the washing process to separate them. The minimum detectable number of biotins was as low as 10 4, corresponding to a sensitivity of 4.8×10-19 mol/ml. This result indicates a high sensitivity of the developed method.
AB - We developed a highly sensitive HTS SQUID system for liquid-phase detection of biological targets using Brownian relaxation of magnetic markers. The SQUID was made of a ramp-edge Josephson junction using RE123-based multilayer process, and it showed a flux noise of 7.5 micro flux-quantam/Hz1/2 in the white noise region. The 1/f noise was 14 micro flux-quantam/Hz1/2 at f = 1 Hz when the SQUID was operated with AC bias mode. Using the SQUID system, we detected a biological target called biotin. In the experiment, biotins were fixed to a large polymer bead with a diameter of 3.3 micron meter. Streptavidin-coated magnetic markers were used for the detection. The bound and unbound (free) markers were magnetically distinguished using the difference in their Brownian relaxation time, i.e., without using the washing process to separate them. The minimum detectable number of biotins was as low as 10 4, corresponding to a sensitivity of 4.8×10-19 mol/ml. This result indicates a high sensitivity of the developed method.
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U2 - 10.1109/ISEC.2013.6604304
DO - 10.1109/ISEC.2013.6604304
M3 - Conference contribution
AN - SCOPUS:84885196800
SN - 9781467363716
T3 - 2013 IEEE 14th InternationalSuperconductive Electronics Conference, ISEC 2013
BT - 2013 IEEE 14th InternationalSuperconductive Electronics Conference, ISEC 2013
T2 - 2013 IEEE 14th InternationalSuperconductive Electronics Conference, ISEC 2013
Y2 - 7 July 2013 through 11 July 2013
ER -