A novel measuring system for the determination of paramagnetic particle labels for use in magneto-immunoassays
A novel measuring system for the determination of paramagnetic particle labels for use in magneto-immunoassays
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DOI：
10.1016/s0956-5663(01)00241-x
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发表时间：
2001-12-01
影响因子：
12.6
通讯作者：
Hawkins, P
中科院分区：
文献类型：
--
作者：
Richardson, J;Hill, A;Hawkins, P
包被的微米大小的顺磁性颗粒（PMP）是容易获得的并且广泛用于免疫测定，主要用于分离和作为固相。我们在另一篇论文中描述了一种模型夹心测定法，其中在测定结束时将约1 × 10（5）至1 × 10（6）PMP（直径22.8 μ m）固定在塑料条上。在本文中，我们描述了一种仪器的设计，能够确定塑料条上的PMP的数量。本文还介绍了一种方法，使标准塑料带与已知数量的PMP对他们。当带与电容器并联放置在线圈中时，由于PMP的存在，导致线圈的谐振频率降低。频率的降低与测试条上PMP的数量直接相关。利用压控振荡器和锁相环组成的电路，精确测量了线圈的谐振频率。该仪器能够检测至少1 × 10（5）个固定在塑料条上的PMPS，并对至少3.33 × 10（6）个PMP具有线性响应（r = 0.99）。就PMPS的铁含量而言，在顺磁性颗粒中的检测极限约为1.2 μ g Fe，灵敏度约为3 Hz/tg Fe。该仪器体积小，结构紧凑，与合适的磁免疫测定一起将具有许多应用，包括近距离患者监测。(C)2001 Elsevier Science B. V.保留所有权利。
Coated micrometer-sized paramagnetic particles (PMPs) are readily available and widely used in immunoassays, mainly for separation and as a solid phase. We have described in a separate paper a model sandwich assay in which approximate to 1 x 10(5) to 1 x 10(6) PMPs (22.8 mum diameter) are immobilised on a plastic strip at the end of the assay. In this paper, we describe the design of an instrument that is capable of determining the number of PMPs on the plastic strip. The paper also describes a method of making standard plastic strips with known numbers of PMPs on them. A strip, when placed in a coil of wire in parallel with a capacitor, causes the resonant frequency of the coil to decrease because of the presence of the PMPs. The decrease in frequency relates directly to the number of PMPs on the strip. A circuit based on a voltage-con trolled oscillator and a phase-locked loop is used to accurately measure the resonant frequency of the coil. The instrument is capable of detecting at least 1 x 10(5) PMPS immobilised on a plastic strip and has a linear response (r = 0.99) for up to at least 3.33 x 10(6) PMPs. In terms of the iron content of the PMPS, the detection limit is approximate to 1.2 mug Fe in the paramagnetic particles and the sensitivity is approximate to 3 Hz per tg of Fe. The instrument is small and compact and together with a suitable magneto-immunoassay will have many applications, including near-patient monitoring. (C) 2001 Elsevier Science B.V. All rights reserved.