Ultrasensitive Magnetic Nanoparticle Detector for Biosensor Applications.
Ultrasensitive Magnetic Nanoparticle Detector for Biosensor Applications.
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DOI：
10.3390/s17061296
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发表时间：
2017-06-06
期刊：
影响因子：
--
通讯作者：
Litvinov D
中科院分区：
文献类型：
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作者：
Liang YC;Chang L;Qiu W;Kolhatkar AG;Vu B;Kourentzi K;Lee TR;Zu Y;Willson R;Litvinov D
采用特高压磁控溅射技术制备了Ta/Ru/Co/Ru/Co/Cu/Co/Ni80Fe20/Ta自旋阀巨磁阻（GMR）多层膜，并对其进行了优化，使GMR比达到13%。利用电子束和光学光刻技术，将GMR多层材料制成12个传感器阵列。采用400 nm × 400 nm和400 nm × 200 nm传感器构建阵列，检测报告纳米颗粒。纳米粒子检测是基于测量磁粒子存在时GMR传感器的高-低电阻开关场的位移。由于形状各向异性和相应的磁场，400 nm × 200 nm传感器的电阻态开关场明显大于400 nm × 400 nm传感器，开关场分布也明显宽。因此，采用400 nm × 400 nm尺寸的传感器阵列进行粒子检测演示。结果表明，该方法可以检测到单个225 nm的Fe3O4磁性纳米颗粒和少量（约10个）100 nm的Fe3O4磁性纳米颗粒。通过适当的功能化生物分子识别，亚微米GMR传感器阵列可以作为超灵敏化学和生物传感器的基础。
Ta/Ru/Co/Ru/Co/Cu/Co/Ni80Fe20/Ta spin-valve giant magnetoresistive (GMR) multilayers were deposited using UHV magnetron sputtering and optimized to achieve a 13% GMR ratio before patterning. The GMR multilayer was patterned into 12 sensor arrays using a combination of e-beam and optical lithographies. Arrays were constructed with 400 nm × 400 nm and 400 nm × 200 nm sensors for the detection of reporter nanoparticles. Nanoparticle detection was based on measuring the shift in high-to-low resistance switching field of the GMR sensors in the presence of magnetic particle(s). Due to shape anisotropy and the corresponding demag field, the resistance state switching fields were significantly larger and the switching field distribution significantly broader in the 400 nm × 200 nm sensors as compared to the 400 nm × 400 nm sensors. Thus, sensor arrays with 400 nm × 400 nm dimensions were used for the demonstration of particle detection. Detection of a single 225 nm Fe3O4 magnetic nanoparticle and a small number (~10) of 100 nm nanoparticles was demonstrated. With appropriate functionalization for biomolecular recognition, submicron GMR sensor arrays can serve as the basis of ultrasensitive chemical and biological sensors.