Kim Kyu Sung, Park Je-Kyun
Department of BioSystems, Korea Advanced Institute of Science and Technology, 373-1 Guseong-dong, Yuseong-gu, Daejeon 305-701, Korea.
Lab Chip. 2005 Jun;5(6):657-64. doi: 10.1039/b502225h. Epub 2005 Apr 29.
This paper describes a novel microfluidic immunoassay utilizing binding of superparamagnetic nanoparticles to beads and deflection of these beads in a magnetic field as the signal for measuring the presence of analyte. The superparamagnetic 50 nm nanoparticles and fluorescent 1 microm polystyrene beads are immobilized with specific antibodies. When target analytes react with the polystyrene beads and superparamagnetic nanoparticles simultaneously, the superparamagnetic nanoparticles can be attached onto the microbeads by the antigen-antibody complex. In the poly(dimethylsiloxane)(PDMS) microfluidic channel, only the microbeads conjugated with superparamagnetic nanoparticles by analytes consequently move to the high gradient magnetic fields under the specific applied magnetic field. In this study, the magnetic force-based microfluidic immunoassay is successfully applied to detect the rabbit IgG and mouse IgG as model analytes. The lowest concentration of rabbit IgG and mouse IgG measured over the background is 244 pg mL(-1) and 15.6 ng mL(-1), respectively. The velocities of microbeads conjugated with superparamagnetic nanoparticles are demonstrated by magnetic field gradients in microfluidic channels and compared with the calculated magnetic field gradients. Moreover, dual analyte detection in a single reaction is also performed by the fluorescent encoded microbeads in the microfluidic device. Detection range and lower detection limit can be controlled by the microbeads concentration and the higher magnetic field gradient.
本文描述了一种新型微流控免疫分析方法，该方法利用超顺磁性纳米颗粒与微珠的结合以及这些微珠在磁场中的偏转作为检测分析物存在的信号。50纳米的超顺磁性纳米颗粒和1微米的荧光聚苯乙烯微珠用特异性抗体固定。当目标分析物同时与聚苯乙烯微珠和超顺磁性纳米颗粒反应时，超顺磁性纳米颗粒可通过抗原-抗体复合物附着在微珠上。在聚二甲基硅氧烷（PDMS）微流控通道中，只有通过分析物与超顺磁性纳米颗粒结合的微珠会在特定施加磁场下移动到高梯度磁场中。在本研究中，基于磁力的微流控免疫分析方法成功应用于检测兔IgG和小鼠IgG作为模型分析物。在背景之上测得的兔IgG和小鼠IgG的最低浓度分别为244 pg mL(-1)和15.6 ng mL(-1)。通过微流控通道中的磁场梯度证明了与超顺磁性纳米颗粒结合的微珠的速度，并与计算出的磁场梯度进行了比较。此外，微流控装置中的荧光编码微珠还实现了在单个反应中对两种分析物的检测。检测范围和检测下限可通过微珠浓度和更高的磁场梯度来控制。
