Self-assembling density gradients for sickle cell diagnosis in low resource areas

用于资源匮乏地区镰状细胞诊断的自组装密度梯度

• 批准号: 8758358
• 负责人: Marta Fernandez-Suarez
• 金额: $ 22.5万
• 依托单位: DAKTARI DIAGNOSTICS, INC.
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-25 至 2016-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8758358
• 关键词: Africa; Africa South of the Sahara; Anemia; Area; Back; Biological Assay; Blood; Blood capillaries; Blood specimen; Businesses; Case-Control Studies; Centrifugation; Characteristics; Child; Childhood; Clinic; Clinical; Coagulation Process; Collection; Comorbidity; Complex; Country; Custom; Detection; Developed Countries; Developing Countries; Development; Devices; Diagnosis; Diagnostic; Diagnostic tests; Disease; Duct (organ) structure; Electrophoresis; Engineering; Environment; Erythrocytes; Evaluation; Fingers; Genotype; Health Technology; Heel; Hemoglobinopathies; Humidity; Individual; Infant; Infection; Laboratories; Lead; Life; Location; Low income; Malaria; Materials Testing; Medical; Methods; Microspheres; Molds; Names; Neonatal Screening; Newborn Infant; Pain; Parasitemia; Penicillins; Performance; Persons; Phase; Pilot Projects; Platelet aggregation; Polymers; Primary Health Care; Property; Quality Control; Reading; Reagent; Recruitment Activity; Reference Standards; Reporting; Research Infrastructure; Resources; Respiratory distress; Running; Rural; Sampling; Sensitivity and Specificity; Sickle Cell; Sickle Cell Anemia; Sickle Cell Trait; Side; Small Business Innovation Research Grant; Source; South Carolina; Specificity; Specimen; System; Teaching Hospitals; Technology; Temperature; Testing; Tube; United States; Universities; Venous; Venous blood sampling; Visual; Work; World Health Organization; Zambia; abstracting; acronyms; base; capillary; cost; cross reactivity; density; design; diagnostic accuracy; disease diagnosis; effective intervention; expectation; global health; improved; infancy; innovation; innovative technologies; instrument; instrumentation; meetings; novel; nutrition; operation; performance tests; point of care; programs; prototype; public health relevance; screening; sickle cell crisis; sickling; success; trait

DESCRIPTION (provided by applicant): The World Health Organization has recently recognized sickle cell disease as a major global health concern. The highest rates of sickle cell disease and sickle cell trait are seen in malaria-endemic developing countries, which also have the most severe resource constraints, especially on clinical laboratory infrastructure. Daktari Diagnostics, a 50-person, venture-backed start-up company focused on the pressing needs for innovative global health technologies is partnering with the Whitesides laboratory at Harvard University and the University Teaching Hospital in Lusaka, Zambia, to develop a novel polymer system into a low-cost, rapid, and simple-to-use assay for the screening and diagnosis of sickle cell disease in resource-limited settings. The sickle cell assay-named Mpana, an acronym for MultiPhase ANAlyzer, and also a Swahili word meaning "a broad, wide, open channel"-is based on self-assembling polymer technology developed by the Whitesides group for industrial and medical applications, and recently shown in preliminary studies in Zambia to be useful for the identification of sickle cells in blood with high sensitivity and high specificity. Moreover, by design these polymer systems are robust and have strong material properties that immediately suggest a path to a commercial product that can meet the difficult constraints necessary for success in resource-limited settings- long shelf-life in environmental extremes, minimal power requirements enabling battery operation, simplicity of use, and, importantly, low cost. The Mpana project described here will transition the promising prototype from the academic setting into a commercial manufacturing environment. For the operator, the final Mpana assay will involve loading capillary blood from a heel stick or finger prick into a small microhematocrit tube pre-filled with multiphase polymers that form step-gradients based on density-and inserting the loaded tube into a small battery-operated centrifugation instrument with a simple user interface. Inside the tube, under centrifugation, dense sickle cells settle to a specific location in the densty gradient, forming a band that can be easily read visually or optically. After approximately 12 minutes, the Mpana system will report out the presence of sickle cell disease, sickle cell trait, o a normal red blood cell profile, and will differentiate HbSS from HbSC disease. Results will be reported either automatically, or by a visual readout, and will be quality controlled through QC reagents included within the microhematocrit tube. To develop the final Mpana assay, we will optimize the current multi-phase polymers developed by the Whiteside group for stability and manufacturability. We will also develop a robust anti-coagulation tube coating and final tube material that will enable easy blood collection for the operator, as well as improve the sensitivit and specificity of the system through the elimination of RBC and platelet aggregation, which can confound the density-based assay performance. In addition, we will develop control microbeads of a fixed, narrow density as on-board QC material, used to confirm the stability of the density gradient. On the instrument side, we will convert what has been an expensive, table-top centrifuge used in the preliminary Harvard studies in Zambia, into a low-cost, portable, battery-operated centrifuge system, a core Daktari expertise for developing simple instrumentation that has been applied previously by the Daktari engineering team to the development of a handheld, battery-operated CD4 system. As a final set of preliminary studies, we will evaluate the performance of the commercial prototype in the context of difficult sample specimens, including specimens containing interfering substances, severe anemia, and a variety of hemoglobinopathies, first in de-identified samples obtained from the Medical University of South Carolina, and finally in an initial pilot study at the University Teaching Hospital in Zambia. We expect the final deliverable from this two-year Phase I SBIR program will be a simple, low-cost instrument and assay tube capable of being used at the primary care level to rapidly and inexpensively identify children with sickle cell disease and sickle trait, at a level of accuracy demonstrably matching or exceeding the expectations of the RFA.

描述（由申请人提供）：世界卫生组织最近将镰状细胞病视为全球主要健康问题。镰状细胞病和镰状细胞性状发病率最高的是疟疾流行的发展中国家，这些国家的资源限制也最严重，特别是在临床实验室基础设施方面。 Daktari Diagnostics 是一家拥有 50 名员工、风险投资支持的初创公司，专注于满足全球创新健康技术的迫切需求，正在与哈佛大学 Whitesides 实验室和赞比亚卢萨卡大学教学医院合作，开发一种新型聚合物系统，使其成为一种低成本、快速且易于使用的检测方法，用于在资源有限的环境中筛查和诊断镰状细胞病。镰状细胞检测名为 Mpana，是 MultiPhase ANAlyzer 的缩写，也是斯瓦希里语，意思是“宽阔、宽广、开放的通道”，基于 Whitesides 小组为工业和医疗应用开发的自组装聚合物技术，最近在赞比亚的初步研究表明，该技术可用于高灵敏度和高特异性地识别血液中的镰状细胞。此外，通过设计，这些聚合物系统坚固耐用，具有强大的材料特性，立即为商业产品提供了一条道路，可以满足在资源有限的环境中取得成功所必需的困难限制——极端环境下的长保质期、支持电池操作的最低功率要求、使用简单，以及重要的是低成本。这里描述的 Mpana 项目将把有前途的原型从学术环境转变为商业制造环境。对于操作员来说，最终的 Mpana 检测将包括将足跟棒或手指刺破的毛细血管血液加载到小型微血细胞比容管中 预填充多相聚合物，根据密度形成阶梯梯度，并将装载的管插入具有简单用户界面的小型电池供电离心仪器中。在管内，在离心作用下，致密镰状细胞沉降到密度梯度中的特定位置，形成一条可以通过视觉或光学轻松读取的条带。大约 12 分钟后，Mpana 系统将报告镰状细胞病、镰状细胞性状或正常红细胞特征的存在，并将区分 HbSS 和 HbSC 疾病。结果将自动或通过视觉读数报告，并将通过微量血细胞比容管中包含的 QC 试剂进行质量控制。为了开发最终的 Mpana 测定，我们将优化 Whiteside 小组当前开发的多相聚合物，以提高稳定性和可制造性。我们还将开发坚固的抗凝管涂层和最终管材料，使操作员能够轻松采集血液，并通过消除红细胞和血小板聚集（这可能会混淆基于密度的测定性能）来提高系统的灵敏度和特异性。此外，我们将开发固定、窄密度的控制微珠作为机载QC材料，用于确认密度梯度的稳定性。在仪器方面，我们将把哈佛在赞比亚的初步研究中使用的昂贵的台式离心机转变为低成本、便携式、电池供电的离心机系统，这是 Daktari 开发简单仪器的核心专业知识，之前已被 Daktari 工程团队应用于开发手持式电池供电 CD4 系统。作为最后一组初步研究，我们将评估商业原型在困难样品样本中的性能，包括含有干扰物质、严重贫血和各种血红蛋白病的样本，首先是从南卡罗来纳医科大学获得的去识别化样本，最后是在赞比亚大学教学医院进行的初步试点研究。我们预计这个为期两年的第一阶段 SBIR 计划的最终成果将是一种简单、低成本的仪器和分析管，能够在初级保健层面使用，以快速、廉价地识别患有镰状细胞病和镰状细胞特征的儿童，其准确度明显符合或超过 RFA 的预期。