The New Jersey Institute of Technology's
Electronic Theses & Dissertations Project

Title:	Aptamer-based nano-scale dielectric sensor for protein detection
Author:	James, Teena
View Online:	njit-etd2009-020 (xiii, 56 pages ~ 4.2 MB pdf)
Department:	Department of Biomedical Engineering
Degree:	Master of Science
Program:	Biomedical Engineering
Document Type:	Thesis
Advisory Committee:	Ivanov, Dentcho V. (Committee chair) Hunter, William Corson (Committee member) Pfister, Bryan J. (Committee member)
Date:	2009-01
Keywords:	Protein detection Nanoscale dielectric sensor Biomolecular recognition Liquid phase
Availability:	Unrestricted
Abstract:	The specific detection and precise quantification of protein molecules play an essential role in basic discovery research as well as in clinical practice. In this research work, a novel protein detection mechanism based on nanoscale dielectric sensor functionalized with aptamer probes is developed. This work has been done in collaboration with Rational Affinity Devices LLC. The use of aptamer based detection offers several advantages over the traditional labor intensive antibody based immunosensing. In the initial phase of the work, the binding affinities of rationally designed oligomers towards a specific protein molecule (IgG) was studied and optimized under varying conditions of ionic strength and pH using fluorescence based methods. Also, various immobilization strategies for aptamer probes including agarose gel based biomimetic surfaces and self assembled monolayers were studied. In the second phase of the sensor development, two separate transduction mechanisms to produce a measurable signal from the immobilized aptamer-protein binding events were analyzed. Initially, a piezoelectric sensing mechanism utilizing the mass of the protein molecules was developed. Although found to be sensitive, this mechanism suffered from viscous damping in liquid phase measurements. Therefore, a novel nanoscale dielectric sensor was developed capable of monitoring biomolecular recognition events in liquid phase with high sensitivity. The use of this sensor for attaining highly sensitive label-free detection of alpha thrombin using immobilized aptamer probes is demonstrated in this work.