Bead magnetorelaxometry with an on-chip magnetoresistive sensor.
Bead magnetorelaxometry with an on-chip magnetoresistive sensor.
复制标题
带有片上磁阻传感器的磁珠磁松弛测量法。
作者：
B. Dalslet;C. Damsgaard;M. Donolato;M. Strømme;M. Strömberg;P. Svedlindh;M. F. Hansen
磁弛豫测量的磁珠悬浮液演示使用嵌入在微流体系统中的平面霍尔效应传感器芯片。用于磁化微珠的交变磁场由传感器偏置电流提供，复磁化率谱记录为传感器响应的二次谐波。当注射磁珠悬浮液时，出现复杂的磁化率信号，它与珠子浓度成正比，并且遵循布朗驰豫的Cole-Cole表达式。复杂的磁化率信号类似于从传统的磁弛豫法在相同的样品上完成，除了在布朗弛豫频率的偏移。信号的时间依赖性可以被合理化为源自沉淀珠。
Magnetorelaxometry measurements on suspensions of magnetic beads are demonstrated using a planar Hall effect sensor chip embedded in a microfluidic system. The alternating magnetic field used for magnetizing the beads is provided by the sensor bias current and the complex magnetic susceptibility spectra are recorded as the 2nd harmonic of the sensor response. The complex magnetic susceptibility signal appears when a magnetic bead suspension is injected, it scales with the bead concentration, and it follows the Cole-Cole expression for Brownian relaxation. The complex magnetic susceptibility signal resembles that from conventional magnetorelaxometry done on the same samples apart from an offset in Brownian relaxation frequency. The time dependence of the signal can be rationalized as originating from sedimented beads.