Construction of Immunoassay system by high sensitve magnetic sensor

近年来，随着分子生物学的发展，对生物分子的高灵敏度分析方法提出了更高的要求。传统的高灵敏度检测方法是基于荧光染料或酶的标记技术。然而，由于这些技术涉及信号不稳定性的一些问题，因此需要新的技术。由于SQUID是一种极高灵敏度的磁传感器，因此可以应用于磁性小颗粒标记的DNA的高灵敏度检测。与荧光染料和酶相比，SQUID的信号稳定，因此它允许长时间和高灵敏度的测量。为了证明这种方法的可用性，制备了通过生物素标记的DNA锚定磁性小颗粒的样品盖玻片。高Tc SQUID传感器对盖玻片的扫描表明，盖玻片上的磁通量与锚定在盖玻片上的标记DNA的图案一致。这一结果表明，SQUID可以应用于DNA分子的特异性检测，特别是用于DNA芯片的检测。

A high sensitive analysis method for biological molecules has been requested accompanied with recent development of molecular biology. Conventional high sensitive detection methods are based on labeling techniques of fluorescent dye or enzyme. However, since those techniques involve some problems on instability of signal, a new technology is desired. Because SQUID is an extremely high sensitive magnetic sensor, it can be applied to high sensitive detection of DNA labeled with magnetic small particles. The signal from SQUID is stable in contrast to fluorescent dye and enzyme, therefore it permits long time and high sensitive measurement.To demonstrate availability of this method, sample coverslips on which the magnetic small particles were anchored through biotin labeled DNA was prepared. Scanning of high Tc SQUID sensor on the coverslip demonstrated that magnetic flux on the coverslip agreed well to the pattern of labeled DNA anchored on the covershp. This result suggests that SQUID can be applied for specific detection of DNA molecules, especially for detection of DNA chips.