%0 Electronic Article %A A. Ramesh %+ Department of Electrical and Computer Engineering, The Ohio State University, Columbus, OH 43210, USA %A F. Ren %+ Department of Electrical and Computer Engineering, The Ohio State University, Columbus, OH 43210, USA %A P.R. Berger %+ Department of Electrical and Computer Engineering, The Ohio State University, Columbus, OH 43210, USA %A P. Casal %+ Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH 43210, USA %A A. Theiss %+ Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH 43210, USA %A S. Gupta %+ Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH 43210, USA %A S.C. Lee %+ Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, OH 43210, USA %K alkali ion dose %K in vivo biosensors %K mobile alkali ions %K PBS solution %K Al2O3 capacitors %K size 100 nm to 10 nm %K threshold voltage %K metal oxide semiconductor capacitor %K triangular voltage sweep technique %K transistor operation %K detectable alkali ions %K silicon dioxide MOS capacitors %K sterile physiological buffer solution %K protein sensing %K alkali ion penetration %K SiO2 %K metal-oxide-semiconductor %K gate dielectric %K high-salt concentration bodily fluids %K impermeability %X In vivo biosensing requires stable transistor operation in high-salt concentration 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 characterised 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. %@ 0013-5194 %T Towards in vivo biosensors for low-cost protein sensing %B Electronics Letters %D March 2013 %V 49 %N 7 %P 450-451 %I Institution of Engineering and Technology %U https://digital-library.theiet.org/;jsessionid=7o1mpqbme70d5.x-iet-live-01content/journals/10.1049/el.2012.4283 %G EN