National Institute of Standards and Technology, Materials Measurement Science Division, Gaithersburg, MD, USA.
Lab Chip. 2013 Oct 7;13(19):3935-44. doi: 10.1039/c3lc50686j.
We present the analytical investigation of a microfluidic homogeneous competitive immunoassay that incorporates antibody-conjugated superparamagnetic nanoparticles and magnetophoretic transport to enhance the limits of detection and dynamic range. The analytical model considers the advective, diffusive, and magnetophoretic transport of the antibody-coated nanoparticles relative to the labeled and sample antigens of interest in a T-sensor configuration. The magnetophoresis-diffusion immunoassay identified clear improvements to the assay response and reductions to the limit of detection for increased magnetophoretic velocities and larger nanoparticles. The externally applied magnetophoretic transport enriched the antibody-antigen accumulation region, while larger nanoparticles led to decreased diffusive peak broadening. The integration of nanoparticles to the diffusion immunoassay (NP-DIA) demonstrated an approximately 3-fold improvement to the limit of detection of the basic antibody/antigen system, while the integration of superparamagnetic nanoparticles and magnetophoretic transport (MIA) established an order of magnitude improvement in sensitivity as well as means to greatly reduce response time. The implementation of an external magnetic force enabled the detectable antigen size spectrum to extend from small molecules i.e., 10's Da to 100's Da, up to large proteins and macromolecules, i.e., 50 kDa to 150 kDa, for a single class of binding species, i.e., superparamagnetic nanoparticle. This investigation provides guidelines for the design and development of a magnetophoresis-diffusion T-sensor immunoassay, and clearly identifies the regimes for optimal operation.
我们提出了一种微流控均相竞争免疫分析的分析研究，该分析结合了抗体偶联超顺磁纳米粒子和磁泳输运，以提高检测限和动态范围。该分析模型考虑了在 T 型传感器配置中，抗体涂层纳米粒子相对于标记和样品抗原的对流、扩散和磁泳输运。磁泳扩散免疫分析确定了磁泳速度增加和纳米粒子增大时，对分析物响应有明显改善，检测限降低。外加的磁泳输运富集了抗体-抗原积累区，而较大的纳米粒子导致扩散峰展宽减小。将纳米粒子集成到扩散免疫分析（NP-DIA）中，与基本的抗体/抗原系统相比，检测限提高了约 3 倍，而超顺磁纳米粒子和磁泳输运的集成（MIA）不仅提高了灵敏度，还大大缩短了响应时间。外加磁场的实施使可检测的抗原大小范围从小分子（例如 10 的 Da 到 100 的 Da）扩展到大分子和大分子，例如 50 kDa 到 150 kDa，适用于单一结合物类别，即超顺磁纳米粒子。本研究为磁泳扩散 T 型传感器免疫分析的设计和开发提供了指导，并明确确定了最佳操作范围。
