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: 8916826
• 负责人: Betsy Wonderly Trainor
• 金额: $ 22.38万
• 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 2018-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8916826
• 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; 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; 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疾病视为全球主要健康问题。在疟疾流行的发展中国家中，镰状细胞病和镰状细胞性状的率最高，这也具有最严重的资源限制，尤其是在临床实验室基础设施上。 Daktari Diagnostics是一家50人，由风险投资支持的初创公司，专注于创新的全球健康技术的紧迫需求，正在与哈佛大学的Whitesides实验室和赞比亚卢萨卡大学的Whitesides实验室合作开发了一个新颖的Polymer系统在资源有限的环境中筛查和诊断镰状细胞疾病的低成本，快速且易于使用的测定法。镰状细胞测定为MPANA，多相分析仪的首字母缩写，也是一个斯瓦希里语单词，意为“一个广阔，宽，开放的渠道” - 是基于WhiteSides工业和医疗应用集团开发的自组装的聚合物技术，以及最近在赞比亚的初步研究中显示，可用于鉴定具有高灵敏度和高特异性的血液中的镰状细胞。此外，通过设计，这些聚合物系统非常强大，具有强大的材料特性，这立即提出了一条通往商业产品的途径，该途径可以满足在资源有限的设置中成功所必需的困难约束 - 在环境极端中长期货架寿命，最小的功率要求实现了能力电池运行，使用的简单性，重要的是低成本。这里描述的MPANA项目将将有希望的原型从学术环境转变为商业制造环境。对于操作员，最终的mpana分析将涉及从脚后跟棒或手指刺中加载毛细血管的血液 预先填充多相聚合物，该聚合物基于密度并将装载的管插入具有简单的用户界面的小电池式离心仪器中，并将其插入载荷管的小型聚合物。在管子内，在离心下，密集的镰状细胞沉降到Densty梯度中的特定位置，形成可以在视觉或光学上轻松读取的频带。大约12分钟后，MPANA系统将报告存在镰状细胞疾病，镰状细胞性状，正常的红细胞细胞状况，并将HBS与HBSC疾病区分开。结果将自动报告，或通过视觉读数进行报告，并将通过微观质外管管中包含的QC试剂来控制质量。为了开发最终的MPANA分析，我们将优化Whiteside组开发的稳定性和生产性开发的当前多相聚合物。我们还将开发出强大的抗凝管涂料和最终管材料，该材料将为操作员提供易于血液的易血，并通过消除RBC和血小板聚集来提高系统的敏感性和特异性，这可能会使密度混淆基于基于测定性能。此外，我们将开发用于固定狭窄密度作为板载QC材料的控制微粒，用于确认密度梯度的稳定性。在乐器方面，我们将将在哈佛大学初步研究中使用的昂贵的，台式离心机转换为一个低成本，便携式，电池式离心机系统，这是一种开发简单仪器的核心专业知识，用于开发简单的仪器Daktari工程团队先前已应用于手持电池操作的CD4系统的开发。作为最终的初步研究，我们将在困难样本样本的背景下评估商业原型的性能，包括含有干扰物质的标本，严重的贫血和多种血红蛋白病，首先是从医疗样品中获得的。南卡罗来纳大学，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，这两年I期SBIR计划的最终可交付能力将是一种简单的低成本仪器和测定管，能够在初级保健水平使用，以快速而廉价地识别患有镰状细胞病和镰状特质的儿童，准确性的水平明显匹配或超过RFA的期望。

项目成果

Fractionating Polymer Microspheres as Highly Accurate Density Standards.

• DOI: 10.1021/acs.analchem.5b01932
• 发表时间: 2015-07
• 期刊: Analytical chemistry
• 影响因子: 7.4
• 作者: William Bloxham;Jonathan W. Hennek;Ashok A. Kumar;G. Whitesides