DEVELOPMENT OF UPCONVERTING NANOPARTICLE/QUANTUM DOT HYBRID STRUCTURE AND MICROFLUIDIC BASED PHOTOELECTROCHEMICAL SENSOR SYSTEM FOR THE DETECTION OF HEPATOCELLULAR CARCINOMA CTDNA

This thesis focused on the detection of Hepatocellular carcinoma (HCC) mutation containing circulating tumour DNA (ctDNA) via static and microfluidic photoelectrochemical sensors employing a nanocomposite of quantum dots (QDs) and upconverting nanoparticles (UCNPs). As HCC is a common type of cancer in the world holding the second place in terms of mortality and could only be diagnosed using invasive approaches, a lab-on-a-chip system based on liquid biopsy biomarkers holds great importance. An electrochemical approach was adapted since DNA detection is well-established with this technique. To further increase the sensitivity of the system, photoelectrochemical (PEC) system was built as a sub-category of electrochemistry where traditional semiconductor QD and rather newly emerged lanthanide doped UCNP pair was used to provide the energy transfer mechanism. The developed specific sensor works with low energy light (980 nm) yielded low limit of detection of 41.4 fM and high sensitivity of 0.014 nA and is proven to be promising for the detection of various other liquid biopsy biomarkers.