A touchscreen as a biomolecule detection platform.

In recent years, considerable effort has been dedicated to the development of a simple, instrument-free detection method that enables point-of-care testing (POCT) and decentralized clinical diagnosis of diseases. One of the most promising approaches to this goal involves the use of an electrical detection strategy. Owing to operational simplicity and ability to be miniaturized, this approach has been subjected to very extensive studies. Nevertheless, except for a glucose sensor or i-STAT blood analyzer, no practical portable POCT device has been developed to date because of the lack of success in readily integrating detection elements into electrical devices. A touchscreen is an input device, generally used in kiosk systems, PDAs (personal digital assistants), or smart phones, that can detect the presence and location of a touch within the device area. Among other touchscreen technologies, including those that employ resistive, infrared, and surface acoustic wave (SAW) signaling, the capacitive touchscreen has been widely used recently owing to the recent increasing popularity of smart phones. Basically, a capacitive touchscreen detects small capacitance changes of electrodes in the device that are induced by a human finger touching event in accord with the relationship shown in Equation (1):

[1]  C. Dekker,et al.  Direct measurement of electrical transport through DNA molecules , 2000, Nature.

[2]  Stefan Boresch,et al.  Studying the Dielectric Properties of a Protein Solution by Computer Simulation , 2000 .

[3]  A. Field.  Communications , 1963, The Journal of Asian Studies.

[4]  Joseph Wang,et al.  Portable electrochemical systems , 2002 .

[5]  D. Klinov,et al.  Proximity-induced superconductivity in DNA. , 2001, Science.

[6]  Sung Jin Kim,et al.  Washing-free electrochemical DNA detection using double-stranded probes and competitive hybridization reaction. , 2004, Chemical communications.

[7]  I. Willner,et al.  Probing Biomolecular Interactions at Conductive and Semiconductive Surfaces by Impedance Spectroscopy: Routes to Impedimetric Immunosensors, DNA‐Sensors, and Enzyme Biosensors , 2003 .

[8]  I-Ming Hsing,et al.  Electrochemical techniques on sequence-specific PCR amplicon detection for point-of-care applications. , 2009, The Analyst.

[9]  H. Fink,et al.  Electrical conduction through DNA molecules , 1999, Nature.

[10]  Rashid Bashir,et al.  Electrical characterization of DNA molecules in solution using impedance measurements , 2008 .

[11]  Mikael Lund,et al.  On the charge regulation of proteins. , 2005, Biochemistry.

[12]  D. Kell,et al.  The passive electrical properties of biological systems: their significance in physiology, biophysics and biotechnology. , 1987, Physics in medicine and biology.

[13]  Booncharoen Wongkittisuksa,et al.  Capacitive biosensor for quantification of trace amounts of DNA. , 2009, Biosensors & bioelectronics.

[14]  F. Young.  Biochemistry , 1955, The Indian Medical Gazette.

[15]  Claude Nogues,et al.  Direct Measurements of Electrical Transport Through Single DNA Molecules of Complex Sequence , 2005 .

[16]  R. Rosenfeld.  Nature , 2009, Otolaryngology--head and neck surgery : official journal of American Academy of Otolaryngology-Head and Neck Surgery.

[17]  D. Buttry,et al.  Recent advances in electrochemical DNA hybridization sensors. , 2010, The Analyst.

[18]  N. Pourmand,et al.  Label-Free Impedance Biosensors: Opportunities and Challenges. , 2007, Electroanalysis.