1. Center for Bioelectronics, Biosensors and Biochips; Clemson University; Anderson SC 29625 USA
2. Department of Chemistry and CASI; The City College of New York; NY 10031 USA
3. Department of Bioengineering; Clemson University; Clemson SC 29634 USA
4. Holcombe Department of Electrical and Computer Engineering; Clemson University; Clemson SC 29634 USA
5. ABTECH Scientific, Inc.; 800 East Leigh Street; Richmond VA 23219 USA