Multifunctional biosensor based on zno nanostructures

Abstract

The present invention provides the multifunctional biological and biochemical sensor technology based on the integration of ZnO nanotips with bulk acoustic wave (BAW) devices, particularly, quartz crystal microbalance (QCM) and thin film bulk acoustic wave resonator (TFBAR). ZnO nanotips provide giant effective surface area and strong bonding sites. Furthermore, the controllable wettability of ZnO nanostructured surface dramatically reduces the liquid consumption and enhances the sensitivity of the biosensor device.

What is claimed is: 
     
         1 . A ZnO nanotip BAW resonator sensor device, comprising:
 a piezoelectric layer;   a conductive film serving as bottom electrode deposited and patterned beneath said piezoelectric layer;   a metal electrode serving as top electrode deposited and patterned on said piezoelectric layer;   ZnO nanotips deposited and patterned on the top surface.   
     
     
         2 . The device of  claim 1  wherein upon binding of the targeted molecules with immobilized biomolecules on said ZnO nanotips causes a mass loading on the BAW resulting in a change in the resonance frequency of the sensor device. 
     
     
         3 . The device of  claim 1  wherein said ZnO nanotips enhance binding strength and immobilization of the DNA, protein, and small biomolecules. 
     
     
         4 . The device of  claim 1  wherein said piezoelectric layer is a single crystal piezoelectric substrate, selected from a group comprising, quartz, lithium niobate, lithium tantalate, etc. 
     
     
         5 . The single crystal piezoelectric substrate of  claim 4  is quartz. The device of  claim 4  is quartz crystal microbalance (QCM). 
     
     
         6 . The device of  claim 1  wherein said piezoelectric layer is a piezoelectric thin film, selected from a group comprising ZnO, Mg x Zn 1-x O, etc. The device of  claim 1  is thin film bulk acoustic wave resonator TFBAR. 
     
     
         7 . A thin film bulk acoustic wave resonator (TFBAR) sensor wherein the device of  claim 6  is mounted on a substrate structure, including, but not limited to, an air-gap structure on the top surface of said substrate, a membrane structure on said substrate, and an acoustic mirror on top surface of said substrate. 
     
     
         8 . The wettability (from superhydrophobicity to superhydrophilicity, or vise versa) of ZnO nanotips of  claim 1  can be controlled. 
     
     
         9 . The superhydrophilic status of the ZnO nanotips of  claim 8  can be obtained through UV shinning. 
     
     
         10 . The superhydrophilicity of the ZnO nanotip surface of  claim 9  is used for the biosensors. It reduces the liquid sample consumption and enhances the sensitivity greatly. 
     
     
         11 . A ZnO nanotip biochip comprised of arrays of ZnO nanotip based BAW sensors and other ZnO nanotip-based sensors, including electrical conductivity based and optical based, can be integrated into a chip, operating simultaneously to realize the multifunction sensing.