Ultra-fast transient cell adhesion and its application for high-throughput microfluidic cell sorting

生物细胞利用其表面的各种粘附分子相互作用并与周围环境相互作用。这些粘附分子的类型、数量和组合携带着关于特定细胞状况的重要信息，可用于表征细胞和诊断疾病。根据粘附分子的表达对细胞进行分选和分离是许多生物医学检测的关键步骤。当前的细胞分选方法使用标签与表达特定粘附分子的细胞结合。这些附加的标签可以实现高纯度的分选，但标签可以改变细胞状态，并可能导致不必要的细胞激活，从而阻止标记细胞的进一步使用。该项目将开发一种微流体技术，该技术可以在不使用任何标签或标签的情况下，根据粘附分子的表达对生物细胞进行快速有效的分选。该技术利用了一种微流体通道，该通道具有周期性收缩，涂层上的分子可以短暂地与细胞表面的粘附分子相互作用。这种相互作用引起感兴趣的细胞轨迹的改变，而不会引起不必要的激活。该项目将研究微通道内细胞相互作用的机制，并将探索使用这种微流体分离技术来分离具有高度特异性粘附分子的淋巴细胞，这些分子可用于癌症治疗。这项研究将涉及本科生和研究生，研究小组将向各个层次的学生开展几项外展活动，包括为科学和工程竞赛开发项目。该项目将开发一种基于分子表面标记物对靶配体亲和力的高通量、无标记细胞分选和分离的微流体方法。识别和分离表达所需分子表面标记的细胞在生物科学、细胞治疗和医学诊断的各种应用中都是必需的。该项目将整合微流体实验和计算机模拟，以在超快时间尺度上研究生物细胞的瞬态粘附，这一点尚未被探索过。细胞将被推动通过一个装饰有对角脊的微流控通道，该微流控通道略微压缩细胞，以促进粘附分子与覆盖在微通道表面的配体之间的结合。结合事件改变了表征细胞粘附的微通道中的细胞轨迹。细胞和微通道表面之间的短接触时间将防止不必要的细胞激活。该项目将在广泛的时间尺度上系统地探索限制对瞬时细胞粘附的影响。此外，该项目将采用微流体细胞分选技术来检测T细胞对靶向抗原的选择性，这在临床应用中很重要，而无需激活细胞。将研究对T细胞新抗原的阳性和阴性选择，以鉴定疾病选择性T细胞。该研究项目是一种用于高通量无标记细胞分离的新型微流体方法，将在医学诊断、治疗、细胞工程和细胞制造方面具有广泛的意义。此外，微流控方法可以直接测量重要生理配体和粘附细胞分子之间的瞬态相互作用，这将有利于开发新的诊断方法。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Biological cells use various adhesion molecules on their surfaces to interact with each other and their environment. The type, amount, and combination of these adhesion molecules, which carry important information about specific cell conditions, can be used to characterize cells and diagnose disease. Sorting and separating cells based on their expressions of adhesion molecules are critical steps in many biomedical assays. Current cell sorting approaches use tags that bind to cells expressing specific adhesion molecules. These attached tags enable high purity sorting, but the tags can alter cell state and can lead to unwanted cell activation preventing further use of the labeled cells. This project will develop a microfluidic technology that enables rapid and efficient sorting of biological cells based on the expression of adhesion molecules without the use of any tags or labels. The technology utilizes a microfluidic channel with periodic constrictions coated with molecules that briefly interact adhesion molecules on the cells' surfaces. The interaction causes a change in the trajectories of the cells of interest without inducing unwanted activation. The project will investigate the mechanics of cell interactions within the microchannel and will probe the use of this microfluidic separation technique to isolate lymphocytes with highly specific adhesion molecules that can be used in cancer therapies. The research will involve undergraduate and graduate students, and the team will conduct several outreach activities to students at all levels, including developing projects for science and engineering competitions.This project will develop a microfluidic approach for high-throughput, label-free cell sorting and separation based on the affinity of molecular surface markers for target ligands. Identifying and isolating cells that express desired molecular surface markers are required in a variety of applications in the biological sciences, cell therapy, and medical diagnostics. The project will integrate microfluidic experiments and computer simulations to examine transient adhesion of biological cells at ultrafast time scales that have not yet been explored. Cells will be propelled through a microfluidic channel decorated with diagonal ridges that slightly compress the cells to promote binding between adhesion molecules and ligands covering the microchannel surfaces. The binding events alter cell trajectories in the microchannel characterizing cell adhesion. The short contact time between cells and microchannel surfaces will prevent unwanted cell activation. The project will systematically probe effects of confinement on transient cell adhesion for a wide range of time scales. Furthermore, the project will employ the microfluidic cell sorting technique to examine T cell selectivity to target antigens, which is important in clinical applications, without activating the cells. Positive and negative selection to T cell neoantigens will be investigated to identify disease-selective T cells. The results of this research project, a new microfluidic method for high-throughput label-free cell separation, will have broad implications in medical diagnostics, therapeutics, cell engineering, and cell manufacturing. Furthermore, the microfluidic method can enable direct measurements of transient interactions between important physiological ligands and adhesive cell molecules that will benefit the development of novel diagnostic methods.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.