Electronic Biosensors For Early Cancer Detection PDF Download

Cancer commences in the building blocks of human body which are cells. In most of the cases, it remains silent in early stage. This is expressed at molecular and cellular levels at primary stages. Recognition of disease at these micro and nano levels might reduce the mortality rate of cancer significantly. This research aimed to introduce novel electronic biosensors for identification of cancer at cellular level. First of all, the dissertation focuses on label-free isolation of metastatic tumor cells using filter based microfluidic devices. Then, nanotextured polymer substrates were implemented for enhanced cancer cell isolation and cell growth. Next, nanotextured microfluidic channel was used for electrical profiling and detection of tumor cells from blood. Finally, a biochip was developed for the detection of tumor cells by electrical profile and surface immobilized aptamer. Standard silicon processing techniques were used to fabricate all of the biosensors. Nantoextruing and surface functionalizon were incorporated to elevate the efficiency of the devices. The first approach aimed to detect cancer cells from blood based on their mechanophysical properties. Cancer cells are larger than blood cells but highly elastic in nature. These cells squeezed through microchannels much smaller than their sizes. The cross-sectional area of the microchannels was optimized to isolate tumor cells from blood. Nanotextured polymer substrates, a platform inspired from the natural basement membrane, were used to enhance the isolation and growth of tumor cells. Micro reactive ion etching was performed to have better control on features of nantoxtured surfaces. Next, electrical measurements of ionic current were performed across single microchannel to detect tumor cells from blood. Later, nanotexturing was shown to enhance the efficiency of the devices by selectively altering the translocation profile of cancer cells. Eventually, aptamer functionalized nanotextured polymer surfaces were integrated with ionic current measurements in a biochip to discriminate tumor cells from blood with higher efficiency and selectivity. These biochip concepts can be implemented in point-of-care devices for the early detection of cancer at cellular level.