Purdue Research Foundation

D Marshall Porterfield

Jonathan Clay Claussen

Aaron Daniel Franklin

Timothy Scott Fisher

Jong Hyun Choi

Alfred R Diggs

Tae-Gon Cha

Jin Shi

Glucose and ATP biosensors have important applications in diagnostics and research. Combining single-walled carbon nanotubes (SWCNTs) with Pt nanoparticles can significantly enhance the performance of electrochemical biosensors. This disclosure illustrates the use of single-stranded DNA (ssDNA) to modify SWCNTs to increase SWCNT solubility in water. Multiple embodiments with this configuration allows for exploration of new schemes of combining ssDNASWCNT and Pt black in aqueous media systems. These embodiments resulted in a nanocomposite with enhanced biosensor performance. The ssDNA-SWCNT/Pt black nanocomposite constructed by a layered scheme proved most effective in terms of biosensor activity. The key feature of this structure and method of use is the exploitation of ssDNASWCNTs as molecular templates for Pt black electrodeposition. Glucose and ATP microbiosensors fabricated utilizing this structure and method of use exhibited high sensitivity, wide linear range and low limit of detection.

Microbiosensors based on DNA modified single-walled carbon nanotube and PT black nanocomposites

Networks of single-walled carbon nanotubes (SWCNTs) decorated with Au-coated Pd (Au/Pd) nanocubes are employed as electrochemical biosensors that exhibit excellent sensitivity (2.6 mA mMcm) and a low estimated detection limit (2.3 nM) at a signal-to-noise ratio of 3 (S/N=3) in the amperometric sensing of hydrogen peroxide. Biofunctionalization of the Au/Pd nanocube-SWCNT biosensor is demonstrated with the selective immobilization of fluorescently labeled streptavidin on the nanocube surfaces via thiol linking. Similarly, glucose oxidase (GOx) is linked to the surface of the nanocubes for amperometric glucose sensing. The exhibited glucose detection limit of 1.3_M (S/N=3) and linear range spanning from 10 &#x3bc;M to 50 mM substantially surpass other CNT-based biosensors. These results, combined with the structure's compatibility with a wide range of biofunctionalization procedures, would make the nanocube-SWCNT biosensor exceptionally useful for glucose detection in diabetic patients and well suited for a wide range of amperometric detection schemes for biomarkers.

Electrochemical biosensor

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West Lafayette, IN, United States of America

D Marshall Porterfield