High-resolution micro-magnetometer based on novel nano-junction oxide SQUIDs

该二期项目将开发一种通用磁性显微镜，并评估其在生物医学中的应用 科学。显微镜将使用高转变温度(High-TC)传感器来检测磁场 基于在第一阶段UC河滨开发的超导量子干涉装置(SQUID) (UCR)开发了一种新的高T_c SQUID制造技术，其结噪声可与 低T_c SQUID。他们的方法使用聚焦的氦离子束使约瑟夫森结的波长为0.5 nm 精确度，从而产生可靠的、可重现的高产量的SQUID。在第一阶段，我们设计了三个 基于这只鱿鱼的磁力计。我们发现直接注入磁强计会产生结噪声 6微米Φo/√赫兹，可与低TC SQUID噪声相媲美。我们把最好的一辆装在一扇窗户下面 倒置显微镜中的显微镜平台，并测定了其在13oK时的场灵敏度为1pT/√赫兹 有效探测器面积为62微米半径。在目标1中，UCR将通过优化 结的尺寸、SQUID环路以及与拾取环路的耦合效率。UCR将构建 1x3鱿鱼薯片，并在第一年交付给特里斯坦。与此同时，特里斯坦将设计和建造一个倒置的 鱿鱼显微镜(ISM)的基础上，他们以前的ISM。它将配备一个直立的荧光灯 上方为显微镜，两侧为微操作器，用于刺激器和记录电极。中的窗口 显微镜工作台将在内部蚀刻微通道，以实现样品之间的距离为10-25微米 以及用于单纳米颗粒和神经元检测的SQUID阵列。这种非常短的差距是可能的，因为 鱿鱼是高温超导体，因此它们的工作温度为10oK。他们会把两条试验用的鱿鱼 芯片放入2x3阵列，并评估它们的灵敏度。一旦构建了工作的ISM，它将被运送到 波士顿在第二年年初评估其在生物医学科学中的效用。在ISM发货后，UCR 将继续改进他们的鱿鱼片。一旦他们实现了探测器噪声的显著降低，波士顿 将把ISM运回特里斯坦，特里斯坦将用改进的鱿鱼芯片测试ISM。特里斯坦将发货 将改进后的ISM送回波士顿继续评估。在《目标2》中，Moment的冈田博士和林博士 波士顿大学(BU)将在第一年使用一个孤立的小龙虾巨型轴突来开发这种磁感应的方法 来自单个神经元的现场检测。北卡罗来纳大学的曼博士将从胎鼠身上培养出海马神经元。 在第二年，冈田和林博士将评估ISM用于测量单个神经元的细胞内电流。在……里面 目标3，马萨诸塞州综合医院马蒂诺斯中心的冈田博士和梅达罗娃博士将建造 纳米颗粒和荧光染料与亲和素和生物素结合。他们将用磁化纳米颗粒 一种交流方法，并测试ISM是否能检测到单个波群。这将作为概念的证明 未来的应用。来自同一复合体的荧光信号将用光学显微镜测量 用于比较研究。第二阶段可交付成果--ISM、业绩报告、出版物。

This Phase II project will develop a general purpose magnetic microscope and evaluate its utility in biomedical sciences. The microscope will detect the magnetic field using high-transition temperature (high-Tc) sensors based on the superconducting quantum interference device (SQUID) developed during the Phase I. UC Riverside (UCR) has developed a novel high-Tc SQUID fabrication technique that gives a junction noise comparable to that of low-Tc SQUIDs. Their approach uses a focused helium ion beam to make the Josephson junction with 0.5 nm precision, resulting in reliable, reproducible SQUIDs with high yields. During Phase I we have designed three magnetometers based on this SQUID. We found the direct injection magnetometer to produce a junction noise of 6 µΦo/√Hz comparable with a low-Tc SQUID noise. We mounted the best one just below the window of a microscope stage in an inverted microscope and determined its field sensitivity at 13oK to be 1 pT/√Hz for an effective detector area of 62 µm radius. In Aim 1, UCR will improve the noise level further by optimizing the dimensions of the junction, the SQUID loop and the coupling efficiency with the pickup loop. UCR will construct 1x3 SQUID chips and deliver them to Tristan in year 1. Tristan, meanwhile, will design and construct an inverted SQUID microscope (iSM) based on their previous iSM. It will be equipped with an up-right fluorescent microscope above and micromanipulators for stimulator and recording electrodes on the sides. The window in the microscope stage will have a micro-channel etched inside to achieve a distance of 10-25 µm between a sample and the SQUID array for single nanoparticle and neuron detection. This very short gap is possible because the SQUIDs are high-Tc superconductors and thus they operate at >10oK. They will mount two of the test SQUID chips into a 2x3 array and evaluate their sensitivities. Once a working iSM is constructed, it will be shipped to Boston for evaluating its utility in biomedical sciences by the beginning of year 2. After shipping the iSM, UCR will continue to improve their SQUID chips. Once they achieve a significant reduction in detector noise, Boston will ship the iSM back to Tristan and Tristan will test the iSM with the improved SQUID chips. Tristan will ship back the improved iSM to Boston for continuing the evaluation. In Aim 2, Dr. Okada of Moment and Dr. Lin of Boston University (BU) will use an isolated crayfish giant axon during year 1 to develop the method for magnetic field detection from single neurons. Dr. Man of BU will develop cultured hippocampal neurons from fetal rats. In year 2, Drs. Okada and Lin will evaluate the iSM for measuring intracellular currents from single neurons. In Aim 3, Dr. Okada and Dr. Medarova of the Martinos Center at Massachusetts General Hospital will construct nanoparticles and fluorescent dye conjugated with avidin and biotin. They will magnetize the nanoparticles using an AC method and test whether the iSM can detect single complexes. This will serve as the proof of concept for future applications. The fluorescent signals from the same complex will be measured with the optical microscope for comparative studies. Phase II deliverables – the iSM, a performance report, publications.