Ultra-sensitive magnetic assays for rapid detection of stroke biomarkers

描述（由申请人提供）：MagneSensors，Inc. I期SBIR用于快速检测中风生物标志物的超灵敏磁性测定项目概述目前的中风治疗受到快速确定谁可以安全地从治疗干预中获益的需要的阻碍。FDA批准的溶栓疗法可以有效治疗急性缺血性中风，最常见的中风，只要在最初的3-4.5小时内给药。许多医生不愿意使用溶栓治疗，因为如果对脑出血（ICH）患者进行溶栓治疗可能是致命的。对血液中的中风生物标志物进行快速简单的诊断测试可能会提供有价值的诊断信息，有助于区分谁应该接受治疗，谁不应该接受治疗。大量研究表明，胶质细胞酸性蛋白（GFAP）是一种很有前途的生物标志物。不幸的是，现有的GFAP测试缺乏足够的灵敏度，具有高度可变性（不是直接定量的），并且花费太长时间。因此，它们甚至不足以用于旨在评价生物标志物的临床研究，也不适合随后的临床应用。我们假设，一种快速、灵敏、定量的GFAP血液检测可以为特定的临床应用提供重要的诊断信息，包括排除 ICH。我们的第一阶段目标是开发这样一种测试，以克服现有测试的缺点。我们提出了一种新的方法，该方法以使用新的磁性纳米颗粒标签和超灵敏的磁性传感器为中心，它们共同提供了独特的优势组合。据我们所知，磁检测分析从未应用于检测中风生物标志物。第一阶段的具体目标是证明GFAP中风生物标志物的磁性免疫测定法具有：1）高分析灵敏度，血液中为2 pg/ml，以及2）快速周转时间，总共50分钟，包括准备和测量。我们还将测量由我们的UCSD卒中中心合作者从缺血性卒中和ICH患者中采集的30份临床血液标本中的GFAP水平。第一阶段GFAP磁性检测的开发将采用一个模型系统，其中将GFAP掺入全血中并捕获在涂有抗GFAP的微球上。涂有检测抗GFAP抗体的磁性纳米颗粒然后与捕获的GFAP结合。来自结合磁性纳米颗粒标记的磁信号用我们最新一代的磁性检测仪器测量，该仪器专为临床环境而设计。新的“混合和测量”形式消除了去除未结合的磁性纳米颗粒标记或红细胞的洗涤步骤的需要，从而能够快速和灵敏地测试血液生物标志物。在第二阶段，我们计划对UCSD合作者提供的标本进行更大规模的前瞻性临床研究。我们希望将总测试时间减少到15分钟或更少，这对于这个时间紧迫的应用程序非常重要。我们还计划评估其他生物标志物，以提高临床敏感性和特异性。第二阶段的目标是收集令人信服的数据，以招募更多的发光点，使多中心的临床研究在第三阶段。最终，我们计划与一家更大的公司合作，将这些测试推向市场。 公共卫生相关性：在美国，每年有近80万人中风，导致14万人死亡，使中风成为第三大死亡原因和长期残疾的头号原因。如果及时给予，脑电刺激疗法可以显着减少对脑细胞的损伤，但目前尚未充分利用，因为很难快速确定何时可以最安全地使用。快速、灵敏地检测血液中的中风生物标志物可以帮助早期诊断，以改善患者的治疗。

DESCRIPTION (provided by applicant): MagneSensors, Inc. Phase I SBIR Ultra-sensitive magnetic assays for rapid detection of stroke biomarkers Project Summary Current treatment of stroke is hampered by the need to rapidly determine who can safely benefit from therapeutic intervention. FDA approved thrombolytic therapy can be effective for acute ischemic stroke, the most common stroke, as long as it is administered within the first 3-4.5 hours. Many doctors are reluctant to use thrombolytic therapy since it can be lethal if administered to patients with intracerebral hemorrhage (ICH). A rapid and simple diagnostic test for stroke biomarkers in blood might provide valuable diagnostic information, helping to sort out who should and should not receive therapy. A number of studies have shown glial fibrillary acidic protein (GFAP) to be a promising biomarker. Unfortunately, existing GFAP tests lack adequate sensitivity, are highly variable (not directly quantitative), and take too long. As such, they are inadequate even for clinical studies designed to evaluate the biomarker as well as unsuitable for subsequent clinical application. We hypothesize that a rapid, sensitive, and quantitative blood test for GFAP could provide important diagnostic information for specific clinical applications that include ruling out ICH. Our Phase I goal is to develop such a test to overcome the shortcomings of existing tests. We propose a new approach that is centered on the use of new magnetic nanoparticle labels and ultra-sensitive magnetic sensors, which together offer a unique combination of benefits. To our knowledge, magnetic detection assays have never been applied to the detection of stroke biomarkers. The Phase I specific aim is to demonstrate a magnetic immunoassay for the GFAP stroke biomarker that has: 1) high analytical sensitivity, 2 pg/ml in blood, and 2) rapid turnaround time, 50 minutes total that includes both preparation and measurement. We will also measure GFAP levels in thirty clinical blood specimens collected from ischemic stroke and ICH patients by our UCSD Stroke Center collaborator. The development of the GFAP magnetic test in Phase I will employ a model system where GFAP is spiked into whole blood and captured on microspheres coated with anti-GFAP. Magnetic nanoparticles coated with detect anti-GFAP antibodies then bind to the captured GFAP. The magnetic signal from bound magnetic nanoparticle labels is measured with our latest generation magnetic detection instrument, which is designed for use in a clinical setting. The novel "mix and measure" format eliminates the need for wash steps to remove unbound magnetic nanoparticle labels or red blood cells, thereby enabling rapid and sensitive tests of blood biomarkers. In Phase II we plan to conduct a much larger prospective clinical study on specimens provided by our UCSD collaborator. We expect to reduce the total test time to 15 minutes or less, which is very important for this time critical application. We also plan to evaluate additional biomarkers to improve clinical sensitivity and specificity. The Phase II goal is to collect convincing data to recruit additional luminary sites t enable multi-center clinical studies in Phase III. Ultimately, we plan to team with a larger company to bring these tests to market. PUBLIC HEALTH RELEVANCE: Nearly 800,000 people have strokes annually in the U.S. leading to 140,000 deaths, making stroke the third leading cause of mortality and the number one cause of long term disability. Proven therapy can significantly reduce damage to brain cells if given in time, but it is currently underutilized as it is difficult to quickly determine when itcan most safely be used. The rapid, sensitive detection of stroke biomarkers in blood could assist early diagnosis to improve patient treatment.