Nanoplasmonic Imaging for Real-time Protein Detection and Cell Secretion Mapping

Abstract

The immune system is composed of a complex network of immune cells, proteins and, chemicals as the first line of defense to protect the human body against pathogens. Monitoring the immune status through disease progression provides extensive correlative analysis for a better understanding of the complex and highly dynamic immune system in modern patient care. Cytokines, cell-signaling proteins produced by a wide variety of immune cells, play pivotal roles in cell proliferation, differentiation, apoptosis, cytotoxicity activation, and cytokine-mediated intercellular communication. Rapid and accurate identification of cytokine-based immune fingerprints for immune monitoring provides valuable clinic information in treating infectious diseases, cancer, autoimmune diseases, etc. Various techniques have been developed for cytokine detection, such as enzyme-linked immunospot (ELASA/ELISpot), intracellular cytokine staining (ICCS), and flow cytometry. These methods provide multiparametric, static information for the traits of immune cells through either average measurement of a group of cells or repeated measurement of individual cells. However, the laborious reagent processing procedures, including multiple-step staining, washing, and blocking, greatly hinder the application of these methods to capture the subtle changes in the immune system for continuous and timely immune analysis of patients. Furthermore, direct visualization of cytokine production, diffusion, and transportation to reveal the fate of the signal mediators among immune cell populations at the single-cell level can provide mechanistic insights into intercellular communication. The aforementioned techniques can only provide quantitative cytokine analysis, while a method for accurate quantification and mapping of the cytokine to provide spatiotemporal information of cytokine secretion in the immune network is surprisingly missing. In this dissertation, we developed integrated optofluidic nanoplasmonic biosensing platforms for rapid, high throughput, sensitive, and multiplex cytokine detection and single-cell secretion imaging. Specifically, three projects were developed and presented as follows: 1) Label-free, ultra-sensitive, high throughput nanoplasmonic biosensor for real-time cytokine detection in amylin aggregation-induced immune responses; 2) Nanoplasmon ruler for direct visualization of single-cell cytokine secretion and cell-cell communication in CAR T-Cell cancer therapy; 3) Nanoplasmon ruler imaging for rapid SARS-CoV-2 RBD protein detection. These platforms for real-time cytokine detection and mapping show great potency in practical applications in immune monitoring, which could ultimately benefit the researchers, clinicians, and patients with better and more effective diagnosis and treatment for immune-related diseases.