Optimized magnetic nanoparticle labels for ultra-sensitive sepsis diagnostics

用于超灵敏脓毒症诊断的优化磁性纳米颗粒标签

• 批准号: 8058824
• 负责人: Mark S. DiIorio
• 金额: $ 19.45万
• 依托单位: MAGNESENSORS, INC.
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-12-01 至 2011-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8058824
• 关键词: Antibiotic Resistance; Antibiotics; Antibodies; Bacteria; Binding; Biological Assay; Blood; Cancer Detection; Cause of Death; Clinical; Coronary Care Units; Custom; Data; Detection; Development; Diagnosis; Diagnostic; Diagnostic tests; Escherichia coli O157; Generations; Goals; Healthcare; Healthcare Systems; High temperature of physical object; Hospitals; Hour; Infection; Intensive Care Units; Label; Laboratories; Lead; Legal patent; Life; Magnetism; Manufacturer Name; Marketing; Measurement; Measures; Methods; Nosocomial Infections; Nucleic Acid Amplification Tests; Organism; Patients; Phase; Polyethylene Glycols; Postoperative Period; Preparation; Reagent; Risk; Running; Sampling; Sepsis; Signal Transduction; Sorting - Cell Movement; Specificity; Specimen; Staging; Staphylococcus aureus; Streptavidin; Surface; Surface Antigens; Testing; Time; Trauma; Urinary tract; Whole Blood; Work; base; clinical Diagnosis; clinically relevant; commercial application; cost; design; experience; improved; innovation; innovative technologies; instrument; magnetic cell separation; magnetite ferrosoferric oxide; nanoparticle; next generation; pathogen; programs; resistant strain; sensor; stem; superconducting quantum interference device; wound

DESCRIPTION (provided by applicant): MagneSensors' program is aimed at developing next generation magnetic nanoparticle labels tailored specifically for ultra-sensitive magnetic assays. These magnetic nanoparticles will be used to detect bacteria leading to sepsis, where there is a strong need for reliable diagnostic tests that are sensitive, specific, and fast. The project takes advantage of an innovative magnetic detection platform where magnetic nanoparticles are attached to antibodies that bind with high specificity to surface antigens on target bacteria. An extremely sensitive magnetic sensor, consisting of a patented high temperature superconducting quantum interference device (SQUID), quantitatively measures the number of magnetic labels bound to the bacteria, and hence the number of bacteria in a sample. These optimized magnetic nanoparticles will enable high sensitivity detection in whole blood using a simple mix and measure format, which is not possible with competing methods. Moreover, the tests can be automated for high throughput and low cost. There is a major emphasis on high sensitivity to enable diagnosis of the pathogen at the earliest possible stage. While the initial focus is on a "proof-of-concept" for the detection of E. coli O157:H7, the platform is applicable to a wide range of bacteria. Sepsis is the tenth-leading cause of death in the U.S. and the second-leading cause of death in non- coronary intensive care unit patients. Existing diagnostic tests are inadequate and there is a large market opportunity available for superior tests, as the health care problem is significant. Note that while competing amplified nucleic acid tests can achieve the necessary sensitivity, there are many challenges to achieving it on clinical specimens. Drawbacks include false positives due to contamination as well as longer turnaround times and other issues that hamper its reliable use for the clinical diagnosis of life threatening infections. The Phase I aims are: 1) to synthesize magnetic nanoparticle labels that have over 50X larger signal (compared to currently used magnetic nanoparticles) and which are stable in blood, and 2) demonstrate sensitive detection of bacteria to 250 CFU/ml in a 45-minute, mix and measure assay in whole blood. In Phase II the sensitivity will be improved further to <50 CFU/ml in as little as 15-20 minutes total assay time, and include additional relevant organisms such as S. aureus along with testing on clinical samples. Magnetic nanoparticles with a larger magnetic signal will be synthesized by increasing the overall volume of the magnetic core as well as the size of the magnetite crystals comprising the core. Minimal aggregation and non-specific binding are critical for stability in whole blood, which is necessarily more difficult for powerful magnetic nanoparticles due to their larger attractive forces. To achieve this stability, we will modify the nanoparticle surface using a method we have developed and successfully employed in prior work. PUBLIC HEALTH RELEVANCE: Sepsis is the tenth-leading cause of death in the U.S., the second-leading cause of death in non-coronary intensive care unit patients, and costs the health care system over $17 billion annually. The ensuing overuse of antibiotics has further resulted in antibiotic-resistant strains of bacteria, significantly increasing the risk of sepsis from hospital-acquired infections, particularly those from post-operative wound, trauma, and the urinary tract. The proposed effort is ultimately focused on rapid, ultra-sensitive diagnostic tests for bacteria that lead to sepsis, enabling the pathogen to be identified at the earliest possible stage to permit timely treatment with the correct antibiotic.

描述（由申请人提供）：Magnesensors的程序旨在开发专门针对超敏感磁性测定的下一代磁性纳米颗粒标签。这些磁性纳米颗粒将用于检测导致败血症的细菌，在这种细菌中，对可靠的诊断测试非常需要敏感，特异性和快速的可靠测试。该项目利用了一个创新的磁性检测平台，其中磁性纳米颗粒附着于靶细菌上表面抗原高特异性结合的抗体。一种极敏感的磁性传感器，由专利的高温超导量子干扰装置（Squid）组成，定量测量与细菌结合的磁标签的数量，从而测量样品中细菌的数量。这些优化的磁性纳米颗粒将使用简单的混合和测量格式在全血中实现高灵敏度检测，这是不可能使用竞争方法的。此外，测试可以自动化高吞吐量和低成本。高度敏感性的重点是在最早的阶段能够诊断病原体。尽管最初的重点是用于检测大肠杆菌O157：H7的“概念验证”，但该平台适用于广泛的细菌。败血症是美国的第十个主要死亡原因，也是非冠状动脉重症监护病房患者的第二个领先原因。现有的诊断测试不足，并且有很大的市场机会可用于卓越测试，因为医疗保健问题很大。请注意，尽管竞争性放大的核酸测试可以达到必要的灵敏度，但在临床标本上实现它存在许多挑战。缺点包括由于污染以及较长的周转时间而造成的假阳性，以及其他问题阻碍了其可靠用于临床威胁生命感染的临床诊断。第一阶段的目的是：1）合成具有超过50倍信号的磁性纳米颗粒标签（与当前使用的磁性纳米颗粒相比），并且在血液中稳定，并且2）在45分钟，混合混合物和量度测量的全血中证明了细菌对250 cfu/ml的敏感检测。在II期中，灵敏度将在总计15-20分钟内进一步提高到<50 cfu/mL，并包括其他相关生物，例如金黄色葡萄球菌，以及对临床样品进行测试。具有较大磁信号的磁性纳米颗粒将通过增加磁芯的整体体积以及包含核心的磁铁矿晶体的大小来合成。最小的聚集和非特异性结合对于全血的稳定性至关重要，这对于强大的磁性纳米颗粒而言，由于其较大的吸引力，这必然会更加困难。为了达到这种稳定性，我们将使用已经在先前的工作中开发并成功使用的方法来修改纳米颗粒表面。 公共卫生相关性：败血症是美国的第十个导致死亡原因，这是非冠军重症监护病房患者的第二个领先死亡原因，每年使医疗保健系统的损失超过170亿美元。随之而来的过度使用抗生素进一步导致细菌抗生素抗性菌株，显着增加了医院获得的感染，尤其是术后伤口，创伤，创伤和尿路的败血症风险。提出的努力最终集中在导致败血症的细菌的快速，超敏感的诊断测试上，从而使病原体能够在最早的可能阶段鉴定出病原体，以允许使用正确的抗生素治疗。