Towards in vivo biosensors for low-cost metal. Finally, aluminium metal was deposited on the backside of the 49protein sensing

In vivo biosensing requires stable transistor operation in high-salt con-centration bodily fluids while exhibiting impermeability to mobile alkali ions that would otherwise render the metal-oxide-semiconductor (MOS) threshold voltage to drift. Metal oxide semiconductor capacitor structures using Al2O3 as the gate dielectric were soaked in a sterile physiological buffer solution (PBS) up to 24 hours and for thicknesses from 100 to 10 nm. The triangular voltage sweep technique character-ised alkali ion penetration, and measured no detectable alkali ions for the Al2O3 capacitors. By contrast, the dose of alkali ions in silicon dioxide MOS capacitors steadily increased with increasing soak times in the PBS solution. Introduction: In the past two decades, research and development of bio-sensors and their applications has undergone remarkable growth [1]. Electrical biosensors have been applied to different target applications, including glucose, pH and protein, detection and measurement