Laser assisted production of nanostructures for biomedical sensing applications

With the recent rise of nanotechnology, the cutting-edge of biosensor technology has rapidly progressed becoming more sensitive, accurate and higher throughput than ever before. However, if nanoengineered biosensors are to become as ubiquitous as ELISA assays in general diagnostic applications they first must become more cost-effective. Current methods for the fabrication of nanobiosensor platforms generally rely on chemical processes that are expensive, environmentally destructive and often time-consuming. As nanotechnology matures from a new, exciting technology into an everyday, mundane one it must also become more affordable and more environmentally friendly. It was noted during polymer ablation experiments that (under specific conditions) laser ablation of bulk metals appeared to result in the direct deposition of nanostructures on the polymer. Following this discovery, work began to optimise this technique (referred to as Confined Atmospheric Pulsed-laser deposition, or CAP) for reliable, reproducible nanostructure deposition and the application of this new technique in the fabrication of biosensors. Such a technique would allow for the rapid, green, inexpensive fabrication of nanostructured films, potentially resulting in the design of a biosensor offering many advantages of the current cutting-edge in sensor technology at a price suitable for use in a Initial experiments explored the capabilities of the CAP technique, discovering suitable metals, substrates and conditions for deposition. Following this, several studies were performed to optimise the technique and search for correlations between processing parameters and the properties of the resulting films. A series of experiments were then performed to adapt this optimised technique to for the deposition of films suitable for biosensor production, such as the direct deposition of interdigitated electrodes. Once a suitable fabrication method had been found, a brief diversion was made to address a difficulty in the characterisation of some reagents needed for that method. This work resulted in the creation of a new, novel, non-destructive technique for particle enumeration in colloidal suspensions. With the design of the sensor finalised, a number of experiments were then conducted to test the effectiveness of the sensor platform for detecting an example target analyte. These tests resulted in the successful detection of c-Myc exon 2 (a cancer biomarker) and the elucidation of dose-response relationships that enables the developed sensor to be used for quantifying the amount of target present in a sample.