A Novel Bioimpedance Sensor for Intracellular Hemoglobin Analysis in Single Sickle Cells

镰状细胞病是一种遗传性红细胞疾病，会影响血红蛋白，即红细胞内的携氧蛋白质。镰状血红蛋白是镰状细胞形态、变形性和血流行为异常的根本原因，导致各种症状和并发症。预计随着时间的推移，并发症和疾病严重程度将发生变化。理解镰状细胞疾病的极端异质性的一个主要挑战是无法测量单个镰状细胞内的镰状血红蛋白。这项研究旨在通过开发一种微型制造传感器来克服这一挑战，该传感器可以在不破坏细胞膜的情况下测量异常镰状血红蛋白的数量。这一跨学科项目为妇女和代表性不足的少数族裔学生提供生物传感、细胞生物物理学、微制造和微流体方面的研究培训。研究成果和技术开发被纳入课程开发，并向本科生和研究生传播。镰状细胞病以其细胞形态、变形性、血液流变学以及严重的临床症状和并发症而闻名，这些症状和并发症与细胞内血红蛋白的变化有关。该项目开发了一种基于微流控技术的单细胞细胞内镰状血红蛋白检测方法，在微流式细胞仪的环境下，利用受控氧气水平下对镰状细胞进行连续生物阻抗检测。将低氧微环境与阻抗传感相结合，可以选择性地测量单细胞中诱导细胞镰状过程中的细胞内镰状血红蛋白变异。三个研究目标包括：(I)建立血红蛋白溶液的生物阻抗分析；(Ii)设计和开发镰状细胞在低氧和高氧水平下的连续阻抗传感；(Iii)单细胞生物阻抗的建模和方法验证，以根据单个镰状细胞的多频阻抗信号表征细胞体积、膜和细胞内血红蛋白成分。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Sickle cell disease is an inherited red blood cell disorder that affects hemoglobin, the oxygen-carrying protein inside the red blood cells. Sickle hemoglobin is the fundamental cause of abnormalities in sickle cell shape, deformability and blood flow behavior, leading to various symptoms and complications. Variabilities in complications and disease severity are expected over time. A major challenge in understanding the extreme heterogeneities of sickle cell disease is the inability to measure the sickle hemoglobin within the single sickle cells. This research aims to overcome this challenge by developing a microfabricated sensor that can measure the amount of abnormal sickle hemoglobin without breaking down cell membranes. This interdisciplinary project provides research training to women and underrepresented minority students, in biosensing, cell biophysics, microfabrication, and microfluidics. The research findings and technological development are incorporated into course development and disseminated to students at undergraduate and graduate levels. Sickle cell disease is known for its extreme heterogeneities in cell morphology, deformability, hemorheology, and severity of clinical symptoms and complications, which are linked to the intracellular hemoglobin variations. This project develops a microfluidics-based single-cell assay of intracellular sickle hemoglobin, using a sequential bioimpedance sensing of sickle cells under controlled oxygen levels in a microflow cytometry setting. Integration of hypoxic microenvironment with impedance sensing allows selective measurement of intracellular sickle hemoglobin variant from the induced cell sickling process in single cells. Three research objectives include: (i) establishment of a bioimpedance analysis of hemoglobin solution; (ii) design and development of a sequential impedance sensing of sickle cells under low and high oxygen levels; (iii) modeling of single cell bioimpedance and method validation for characterization of cell volume, membrane and intracellular hemoglobin composition from the multi-frequency impedance signal of single sickle cells.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.