AC and Phase Sensing of Nanowires for Biosensing.
Silicon nanowires are label-free sensors that allow real-time measurements. They are economical and pave the road for point-of-care applications but require complex readout and skilled personnel. We propose a new model and technique for sensing nanowire sensors using alternating currents (AC) to capture both magnitude and phase information from the sensor. This approach combines the advantages of complex impedance spectroscopy with the noise reduction performances of lock-in techniques. Experimental results show how modifications of the sensors with different surface chemistries lead to the same direct-current (DC) response but can be discerned using the AC approach.
Department of Electrical, Electronic and Information Engineering, University of Bologna, Cesena Campus, Cesena 47521, Italy. marco.crescentini3@unibo.it.
Marco
M
Crescentini
Department of Electrical, Electronic and Information Engineering, University of Bologna, Cesena Campus, Cesena 47521, Italy. michele.rossi@unibo.it.
Michele
M
Rossi
School of Electronics and Computer Sciences, and the Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, UK. pa@ecs.soton.ac.uk.
Peter
P
Ashburn
School of Electronics and Computer Sciences, and the Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, UK. ml09v@ecs.soton.ac.uk.
Marta
M
Lombardini
Department of Electrical, Electronic and Information Engineering, University of Bologna, Cesena Campus, Cesena 47521, Italy. enrico.sangiorgi@unibo.it.
Enrico
E
Sangiorgi
School of Electronics and Computer Sciences, and the Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, UK. hm@ecs.soton.uk.
Hywel
H
Morgan
Department of Electrical, Electronic and Information Engineering, University of Bologna, Cesena Campus, Cesena 47521, Italy. marco.tartagni@unibo.it.
Marco
M
Tartagni
D000465:Algorithms; D015374:Biosensing Techniques; D017097:Electric Impedance; D004560:Electricity; D044085:Microfluidics; D008962:Models, Theoretical; D053770:Nanowires / Q000737:chemistry*; D012825:Silicon / Q000737:chemistry
D012825:Silicon
AC sensing; impedance spectroscopy; nanosensors; nanowires; phase detection