Immunofluorescence detection of quantum dot labeled cancer cells: Microcontact printing, nanoporous surface enhanced absorption, and microfluidic applications

Detection of circulating tumor cells (CTCs) in blood has been rapidly developing into a promising early cancer diagnostic tool. CTCs provide crucial evidence of the progression and status of the disease. Early cancer detection provides a powerful prevention step, allowing for effective treatment. This thesis presents an efficient method for cancer cell capture via cell line-specific antibody deposition and adsorption on nanoporous silica substrates using a method called “micro-contact printing” and immunofluorescence detection through quantum dot labeling within a microfluidic system. Microcontact printing is essential in efficient design, characterization, and production of biologics for cost effective, high throughput, and point-of-care detection and analysis system. Nanoporous silica enhances the adsorption of proteins onto its surface. Quantum dots enable brighter and stabler fluorescence imaging of biological species. Additionally, microfluidic systems allow for more effective antibody-antigen interactions due to physical dimensional constraints of the microfluidic channel itself, forcing closer proximities between antigen and antibody, thus increasing binding probabilities. Coupled together, a compact system for efficient and effective microchip-based diagnostics and detection can be designed. Such a system sets the stage for a versatile platform capable of being manipulated for different biological applications. Furthermore, it provides additional advantages that make it a more desirable biosensing platform, such as multiplexing and multicolor detection capabilities. Potential applications include high throughput drug assays, site-specific cell culturing, cellular biomarker studies, and cancer cell detection. Each component of the platform plays an important role in enhancing the sensitivity and specificity of the aforementioned applications.Biomedical Engineerin