Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Lab Chip. 2012 Nov 7;12(21):4433-40. doi: 10.1039/c2lc40715a.
An integrated platform for the capture, transport, and detection of individual superparamagnetic microbeads is described for lab-on-a-chip biomedical applications. Magnetic domain walls in magnetic tracks have previously been shown to be capable of capturing and transporting individual beads through a fluid at high speeds. Here it is shown that the strong magnetostatic interaction between a bead and a domain wall leads to a distinct magneto-mechanical resonance that reflects the susceptibility and hydrodynamic size of the trapped bead. Numerical and analytical modeling is used to quantitatively explain this resonance, and the magneto-mechanical resonant response under sinusoidal drive is experimentally characterized both optically and electrically. The observed bead resonance presents a new mechanism for microbead sensing and metrology. The dual functionality of domain walls as both bead carriers and sensors is a promising platform for the development of lab-on-a-bead technologies.
本文描述了一种用于捕获、传输和检测单个超顺磁微珠的集成平台，适用于微流控生物医学应用。先前已经证明，磁畴壁在磁道中能够以高速捕获和传输单个微珠。本文表明，微珠与畴壁之间的强静磁相互作用导致了明显的磁机械共振，反映了捕获微珠的磁化率和流体动力尺寸。数值和分析建模用于定量解释这种共振，并且通过光学和电学方法实验表征了在正弦驱动下的磁机械共振响应。观察到的微珠共振为微珠传感和计量学提供了一种新的机制。畴壁作为微珠载体和传感器的双重功能是开发基于微珠的技术的有前途的平台。
