Certain investigations on screen printed electrodes for biomedical applications

Abstract

Ion selective electrodes (ISEs) play an important role in clinical diagnostics for the monitoring of blood electrolytes and blood gases. Conventional ion selective electrodes are bulkier and the analyzers designed based on them are laboratory intensive. Most of the commercial blood electrolyte analyzers are desk top models. It would be desirable to miniaturize the ion selective electrodes so that a portable bed side monitoring system can be fabricated. In this context, screen printed electrodes are the alternate candidates for the fabrication of ISEs. Already, screen printed electrode based glucose biosensor has been commercialized and is extensively used in hospitals and as monitoring from home device. It contributes 85% utility of screen printed electrode. Currently, screen printed ion selective electrodes (SPE-ISE) have the following draw backs. Firstly, Screen Printed Planar Reference Electrodes (SSPRE) that has stable, reproducible with a long life has not been achieved. Most of the reported SSPREs have potential drift as a function of time due to the loss of chloride ion from them. Secondly, there is solution seepage between the dielectric layer of the SPE and the polymer membrane used for the fabrication of SSPRE and SPE-ISE. In the instrumentation side, Raspberry pi system is used for the fabrication of instruments as the system if more powerful single chip computer. Hence, the thesis aims at the design of screen printed electrodes that will have a well type of structure surrounding the electrode and the dielectric layers. The thesis comprises the design of screens for printing as described above, fabrication of screen printed electrode newline