Molecular And Textural Surface Engineering For Biological Sensing

Abstract

This research work was aimed at finding novel approaches for early cancer detection. In cancer diagnosis, the candidate molecules largely include free DNA, related proteins and tumor cells, listed in increasing order of size. The list is also commonly accepted as early precursor of the disease where DNA and proteins are available in patients' blood earlier and the cell starts to appear in relatively later stage. The ratio of these molecules to the background matter is extremely small. To make detection more difficult, these molecules, once dislodged from their primary location, get cleared fast. These factors call for extremely sensitive and efficient devices that won't let the trace amount of molecules pass without getting detected.The first approach was focused on finding a novel method towards detecting the disease by analyzing the cell behavior on a functionalized surface. Cancer cells that remained calm with few to no movement on a generic surfaces were found to display elevated motility on a surface coated with specific RNA sequence. This RNA sequence bound complementarily to growth factor receptors that are commonly found in excess on the cancer cell surface. This behavior was analyzed using image processing techniques and it was found that there were distinguishing parameters between cancer and healthy cells.In an attempt to increase the capture efficiency of the cancer cells, a platform inspired from the natural basement membrane was fabricated. The 3-D structure involved micro-nano texturing using simple processing. The substrate was economical and took minimal time to prepare. It was found to capture cells from a mixture with superior efficiency.Nanopore is a platform for detecting smaller molecules like DNA and proteins. The underlying mechanism when a molecule passes through the pore is very difficult to observe from outside but holds crucial information. As a result, molecular dynamics simulations that revealed the interaction between two molecules at atomic level were used to understand the protein-DNA interactions and the structural integrity of these molecules in experimental conditions. This parallel development of the technique is bound to pace up the nanopore research.