Quantitative Nano-Surface Chemistry for Diabetes Serum Biomarker Assays

Abstract

Glucose monitoring devices (e.g., glucometer) are widely established as a successful diabetes management and point-of-care testing systems. However, non-glucose markers such as hormones, autoantibodies, proteins, and other small molecules can provide better assessments for the prediction and management of the disorder and identification of diabetes classes (e.g., type 1 and type 2). The challenges our research community faces in designing an analytical device for such markers are the dynamic range, limit of detection, selective isolation of the analyte, higher background noise due to clinical matrix, and ability to transform the system into a cheap point-of-care device. The main research objective is to design and develop a new diabetes sensor surface chemistry to advance the current analytical capabilities of detecting serum insulin and autoantibodies through novel surface designs.

In this dissertation, I discuss the development of covalent and noncovalent carboxylations of carbon nanotubes for sensitivity enhancement of clinical immunosensors for insulin detection. Additionally, the validation of an electrochemical immunosensor for detection of serum glutamic acid decarboxylase-65 autoantibody through surface plasmon resonance imaging and establishing binding parameters for the antigen-antibody binding are reported. Finally, a low-cost paper-based label-free electrochemical approach is presented for sensitive detection of serum insulin. The dissertation critically discusses the quantitative analytical details of the developed sensors' surfaces.