An integrated bionanosensing method for airborne toxin detection

Nanoscale sensing arrays utilizing the unique properties of the optical protein bacteriorhodopsin and colloidal semiconductor quantum dots are being developed to detect minute concentrations of airborne toxins. This paper describes an innovative method to activate bacteriorhodopsin-based sensors with the optical output of quantum dots, producing a measurable electrical response from the protein. The ability of quantum dots to activate nanoscale regions on bacteriorhodopsin-based electrodes allows sub-micron sensing arrays to be created due to the ability to activate site-specific regions on the array. A novel method to modulate the sensor's electrical output to obtain both "on" and "off" states is also achieved utilizing the fluorescence resonance energy transfer characteristics of a bacteriorhodopsin/quantum dot system. Apart from applying this technology to toxin detection arrays, the ability to readily manipulate the protein's electrical and optical characteristics could have implications in other areas of nanobiotronics.