(1) Biosensor development: Inlaid CNF nanoelectrode arrays are employed as electronic sensors. The exposed tip of CNFs is selectively functionalized with oligo- nucleotides, antibodies, or peptides for the development of electrochemical or impedance-based sensors to detect nucleic acids, antigens, and kinase activities. In another configuration, the inlaid nanoelectrode array is fabricated in a microfluidic channel as a highly effective dielectrophoresis (DEP) device for bioparticle trapping and sensing. An integrated biochip for bacteria detection is under development in collaboration with industrial partners.

 

DNA sensors by nanoelectrode array

Capture bacteria by DEP using CNF nanoelectrode arrays

 

 

 

 

 

 

 

 

(2) Biomedical devices: Vertically aligned CNFs are used as a brush-like electrode to interface with tissues. A conductive polymer coated on the vertical CNF array is being explored as a multi-functional neural electrical interface to provide topographical, mechanical, chemical, and electrical support of neural network. The modification of the surface with conductive polymers further improves the biocompatibility as investigated with neuronal cell culture. Electrical stimulation/recording with rat hippocampal slices has shown much improved efficiency, indicating a more intimate neural electrical interface than planar microelectrode arrays.

3D neural electrical interface

3x3 array of CNF microbrushes

PC12 cells on PPy-coated CNF arrays

 

(3) Solid-state nanodevices: Novel integration and fabrication methods are developed for applications of CNTs, CNFs, and inorganic NWs as on-chip integrated circuit interconnects, thermal interface materials, transistors, and chemical/biochemical sensors. We are currently working on further evaluation and optimization of both materials properties and processes.

 

ZnO nanowires bridging two microelectrodes

2-terminal I-V curve of a ZnO nanowires

(4) Energy conversion and storage: The large surface area of CNTs and NWs is attractive for the development of new solar cells, supercapacitors, and lithium ion batteries. Particularly, a TiO2 film deposited on the vertically aligned CNF array by MOCVD has shown an interesting nanoneedle structure. Such core-shell materials have been demonstrated as a novel dye-sensitized solar cell (DSSC) architecture. The fundamental understanding of energy conversion through materials and interface modification is being pursued in a collaboration involving researchers from all three major universities in Kansas, which is recently supported by the NSF EPSCoR program.

Solar cells for energy conversion

ZnO-coated CNF array DSSC architecture

The nanoneedle morphology of ZnO coating on CNF arrays

I-V characterization of the DSSC

 

 

Kansas State University Chemistry Department