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确认为一个主要的全球健康问题。镰状细胞病和镰状细胞性状的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名员工的风险投资支持的初创公司，专注于创新全球健康技术的迫切需求，正在与哈佛大学的Whitesides实验室和赞比亚卢萨卡的大学教学医院合作，开发一种新型聚合物系统，用于在资源有限的环境中筛查和诊断镰状细胞病。镰状细胞分析-名为Mpana，是MultiPhase ANAlyzer的首字母缩写，也是斯瓦希里语中的一个词，意思是“一个广阔，宽阔，开放的通道”-基于Whitesides集团开发的用于工业和医疗应用的自组装聚合物技术，最近在赞比亚的初步研究中显示，可用于识别血液中的镰状细胞，具有高灵敏度和高特异性。此外，通过设计，这些聚合物系统是稳健的并且具有强的材料性质，其立即暗示了通向商业产品的途径，该商业产品可以满足在资源有限的环境中取得成功所必需的困难约束-在极端环境中的长保质期、使电池运行的最小功率要求、使用简单性以及重要的低成本。这里描述的Mpana项目将把有前途的原型从学术环境过渡到商业制造环境。对于操作者，最终的Mpana检测将涉及将来自脚跟棒或手指刺的毛细血管血加载到小的微量血细胞比容管中 预填充有多相聚合物，该多相聚合物基于密度形成阶梯梯度，并将装载的管插入具有简单用户界面的小型电池操作的离心仪器中。在试管内，在离心作用下，密集的镰状细胞沉降到密集梯度中的特定位置，形成可以容易地通过视觉或光学读取的条带。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谱的存在，并将区分HbSS和HbSC疾病。将自动或通过目视读数报告结果，并通过微量红细胞压积管中的QC试剂进行质量控制。为了开发最终的Mpana检测试剂盒，我们将优化Whiteside小组开发的当前多相聚合物的稳定性和可制造性。我们还将开发一种耐用的抗凝试管涂层和最终试管材料，使操作员能够轻松采集血液，并通过消除RBC和血小板聚集来提高系统的灵敏度和特异性，这可能会混淆基于密度的测定性能。此外，我们将开发固定、窄密度的对照微珠作为机载QC材料，用于确认密度梯度的稳定性。在仪器方面，我们将把哈佛大学在赞比亚进行的初步研究中使用的昂贵的台式离心机改造成低成本、便携式、电池供电的离心机系统，这是达科塔利开发简单仪器的核心专长，此前达科塔利工程团队已将其应用于开发手持式、电池供电的CD 4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本标本中的性能，包括含有干扰物质的标本、严重贫血和各种血红蛋白病，首先是在从南卡罗来纳州医科大学获得的去识别样本中，最后是在赞比亚大学教学医院的初步试点研究中。我们预计，这一为期两年的第一阶段SBIR计划的最终成果将是一种简单、低成本的仪器和检测管，能够在初级保健水平上快速、廉价地识别患有镰状细胞病和镰状性状的儿童，其准确度明显匹配或超过RFA的预期。