Biomimetic Multifunctional Device for Quantification and Analysis of Circulating Tumor Cells (CTC)

从血液中选择性检测和分离循环肿瘤细胞（CTC）为疾病诊断和预后提供了有价值的临床见解，因为CTC已被证明是疾病进展和生存的独立预测因子。 此外，准确的CTC数字可用于通过监测治疗期间肿瘤的变化来管理疾病。 然而，CTC是极其罕见的，在患有转移性癌症的患者的血液中仅包含109个血液细胞中的一个，有效地识别和分离稀有细胞仍然是一个巨大的挑战。 该提案的中心目标是在微流体芯片内模拟生理细胞行为，该微流体芯片可以以高效率和特异性分离和捕获CTC。 为了提高稀有细胞的灵敏度和捕获效率，利用多价效应将是有用的，因为已观察到该效应导致结合亲和力呈指数级增加。 通过由球形聚（酰胺基胺）树枝状聚合物和线性聚乙二醇组成的聚合物纳米接头控制抗上皮细胞粘附分子（抗EpCAM）的固定将允许控制多价表面以最大化CTC的捕获。 此外，由于已知转移的第一步是CTC在表达选择素的血管内皮上的"滚动"，因此包被有诱导天然存在的滚动过程的蛋白质的表面将促进靶细胞从流中募集出来，从而进一步增强针对细胞的特异性。 因此，在这里，研究人员提出了一种新的CTC捕获装置的设计，它模拟了两个重要的生物过程：多价结合和细胞滚动。 此外，工程化微流体通道将诱导流动的旋转，这将显著增加细胞与功能化捕获表面的相互作用。 具体而言，本工作的目标将集中于：1）设计和制造仿生微流控芯片，以利用滚动和多价强结合来分离和捕获CTC; 2）表征和优化微流控芯片利用肿瘤细胞系的捕获效率和特异性。目前的计划是独一无二的，因为它将模仿自然发生的过程，用于晚期癌症患者的潜在诊断应用。 使用仿生学和工程微通道的组合策略将在血液中稀有细胞检测的新兴领域具有重大意义和潜在的高回报。 假设基于CTC的迭代滚动和静止粘附的仿生微流控芯片将有效地检测和分离稀有细胞。 将决定CTC捕获效率的基本参数是：1）靶细胞与抗EpCAM之间的多价结合，所述抗EpCAM通过柔性聚合物纳米接头的固定而局部浓缩，和2）通过由通道顶部中的凹槽引起的流动旋转而使细胞与官能化基底之间的相互作用最大化。 该研究小组将扩大现有的教育和推广活动的个人研究者，包括高中实习计划和研究经验的本科生。 伊利诺伊大学芝加哥分校（UIC）的女性和少数民族本科生比例很高，第一代大学生预计将成为美国在21世纪世纪取得科学进步的支柱。 该计划中开发的研究成果和实验技术将被整合到本科和研究生阶段的课堂教学中。

0931472HongSelective detection and isolation of circulating tumor cells (CTCs) from blood provide valuable clinical insight into disease diagnosis and prognosis as CTCs have been demonstrated to be an independent predictor of disease progression and survival. Additionally, accurate CTC numbers can be used to manage the disease by monitoring changes in tumors during treatment. However, CTCs are extremely rare, comprising as few as one in 109 hematologic cells in the blood of patients with metastatic cancer, effective recognition and separation of the rare cells remain a tremendous challenge. The central objective of this proposal is to mimic physiological, cellular behaviors within a microfluidic chip that can separate and capture CTCs with high efficiency and specificity. To increase sensitivity and capturing efficiency of the rare cells, exploiting multivalent effects will be useful since the effect has been observed to result in an exponential increase of binding avidity. Controlled immobilization of anti-epithelial-cell-adhesion-molecule (anti-EpCAM) through polymeric nanolinkers composed of spherical poly(amidoamine) dendrimers and linear polyethylene glycol will allow control over the multivalent surface to maximize the trapping of CTCs. Furthermore, as the first step of metastasis is known to be "rolling" of the CTCs on the endothelia of blood vessels that express selectins, surfaces coated with the protein that induces the naturally occurring rolling process will promote recruitment of the targeted cells out of the flow, thereby further enhancing specificity against the cells. Hence, here the investigators propose a new design of a CTC capturing device that mimics two important biological processes: multivalent binding and cell rolling. In addition, engineered microfluidic channels will induce rotation of flow that will substantially increases the cell interactions with the functionalized capturing surfaces. Specifically, the objectives of this work will focus on: 1) design and fabrication of a biomimetic microfluidic chip to separate and capture CTCs using rolling and multivalent strong binding; 2) characterization and optimization of capturing efficiency and specificity of the microfluidic chip using tumor cell lines. The present program is unique in that it will mimic naturally occurring processes for potential diagnostic applications of late-stage cancer patients. The combined strategies of using the biomimicry and engineered microchannels will have great implications and potentially high-reward in the emerging area of rare cell detection in blood. It is hypothesized that a biomimetic microfluidic chip based on iterative rolling and stationary adhesion of CTCs will effectively detect and isolate the rare cells. Essential parameters that will determine the efficiency of CTC trapping are: 1) multivalent binding between the targeted cells and anti-EpCAM that is locally concentrated via immobilization through flexible polymeric nanolinkers and 2) maximized interaction between cells and the functionalized substrate through flow rotation caused by grooves in the channel ceiling. The research team will expand the existing education and outreach activities of the individual investigators, including a high-school internship program and a research experiences for undergraduates. The University of Illinois at Chicago (UIC) has a high proportion of women and racial minority undergraduates, as well as first-generation college students who are projected to be the backbone of the scientific progress made by U.S. in the 21st century. The research results and experimental techniques developed in this program will be integrated into classroom instruction, both at the undergraduate and graduate levels.