电磁铁辅助磁性金属异物取出术28例体会

<正>磁性微细金属异物在骨科急诊、门诊诊治中经常遇到。这些患者大多要求行金属异物取出术。微细金属异物存留体内多为爆炸伤、机器压榨伤、铁砂枪弹伤、肌肉注射针头折断所致。有些外科医生低估了手术的难度程度,往往以失败而告     

Sensitive and rapid immunoassay for parathyroid hormone using magnetic particle labels and magnetic actuation

A rapid method for the sensitive detection of proteins using actuated magnetic particle labels, which are measured with a giant magneto-resistive (GMR) biosensor, is described. The technique involves a 1-step sandwich immunoassay with no fluid replacement steps. The various assay binding reactions as well as the bound/free separation are entirely controlled by magnetic forces induced by electromagnets above and below the sensor chip. During the assay, particles conjugated with tracer antibodies are actuated through the sample for target capture, and rapidly brought to the sensor surface where they bind to immobilized capture antibodies. Weakly or unbound labels are removed with a magnetic force oriented away from the GMR sensor surface. For the measurement of parathyroid hormone (PTH), a detection limit in the 10 pM range is obtained with a total assay time of 15 min when 300 nm particles are used. The same sensitivity can be achieved in 5 min when 500 nm particles are used. If 500 nm particles are employed in a 15-minute assay, then 0.8 pM of PTH is detectable. The low sample volume, high analytical performance and high speed of the test coupled with the compact GMR biosensor make the system especially suitable for sensitive testing outside of laboratory environments.