Low-cost Zinc Oxide Nanorods Modified Paper Substrate for Biodiagnostics
thesisposted on 16.07.2018, 04:53 by Sadhana Tiwari
Many of the point-of-care hand-held devices are based on the detection of very low concentrations of some specific protein biomarker in a blood or biofluid sample. There is an often need to preconcentrate by a few orders of magnitudes the analyte prior to measurement on the sensing area of the test to enhance the detection sensitivity for these miniaturized devices. Protein preconcentration is one of the major challenges in biosensing with miniaturized devices as enhancement of detection sensitivity for highly diluted analytes is critical and required for its better performance. Besides preconcentration, blood-plasma separation is another major challenge in biodiagnostics. The conventional blood-plasma separation involves centrifugation, which generally enables very efficient and fast results. But in case of point-of-care miniature devices it is necessary to have an integrated miniature blood-plasma separation system to reduce the number of sample preparation steps and quick diagnosis. Substantially-reduced total cost of ownership and usage are being seen as increasingly necessary to ensure affordable healthcare for a growing world population. In this context paper-based devices are gaining popularity as they are inexpensive, easy to fabricate and to modify, and once used, easy to dispose as they easily burn and are biodegradable. Paper has inherent capillary force created by the network of cellulose therefore, no external driving force or systems are required for fluid transport. Paper also provides a good support for growing nanostructures by providing a template for orientation and nucleation sites. The work presented in this thesis involves, modification of paper with ZnO nanostructures to increase the available surface area for protein capture, biofunctionalization of nanostructures-modified paper. Emphasis is given on developing a protocol for protein preconcentration using the nanorods modified paper as a substrate and its confirmation by surface plasmon resonance, which also provided an opportunity to explore SPR studies on the ZnO nanorods modified gold chip. In addition to this passive separation of blood cells from plasma with the 1-D ZnO nanostructures modified paper as a substrate is also explored.