Nanostructured Interfaces for Single Molecule Sensing and Molecular Fingerprinting

Nanoscale interfaces can have a profound influence on sensor performance, arising from the increased surface-area-to-volume ratio on length scales <100 >nm, and often on the emergence of new phenomena on this length scale and even enhancement of existing phenomena. These interfaces can be used to form sensing devices capable of molecular sensing and fingerprinting. Attaining rapid and reliable molecular information with low analyte concentrations and minimal instrument overhead is crucial for many fields including the pharmaceutical industry, food quality analysis, biomedicine, water quality analysis, etc., to meet the current demands of sample analysis. Nanoscale elements in these nanosensors, in amalgam with other physical and chemical driving forces are useful for attaining low limits of detection with the ultimate goal of observing one molecule-at-a-time. This proposal contains two approaches to develop nanostructured sensors—one optical and one non-optical—to reach this goal. The first study is designed to develop a non-optical sensor—a solid state nanopore—for carbohydrate biopolymers—a class of abundant biomolecules that nevertheless have not been extensively characterized like other biomolecules (DNA or proteins), due to inadequate sensing capabilities to easily tackle the molecular complexity by classical methods alone. Additionally, methods to enhance and control the pore surface chemistry are investigated. Second, a series of accessible and low-cost surface enhanced Raman substrates are fabricated on a range of supports using electroless gold plating, to create optical sensors with vibrational selectivity and multifunctional capabilities.