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ZnS/Silica Nanocable as Biological Nanosensors Using Avidin-Biotin System: Nanodevice Fabrication and Application

Jr-Hau He 1Chih H. Ho 

1. National Taiwan University, Dept. of Electronic Engineering, Taipei 1-06, Taiwan


Compound semiconductor/isolator (ZnS/silica) core/shell nanocables have been used to fabricate field effect transistors (FETs) using focused ion beam (FIB), which involved two major steps. First, cutting the nanocables to bare ZnS core using FIB could be achieved by accelerating concentrated Gallium ions to a specific site, which etches off any selected area, leaving a very clean surface of ZnS core. Secondly, the Pt mixture was selectively deposited using FIB to contact the prepatterned electrodes and ZnS core. Electrical characteristics of nanocable-based FET show the typical behavior for n-type FET devices.

To explore NWs-based sensors for biological recognition, silica shell of nanocable was functionalized with biotin. Biontinylation reagent used here is amine-reactive to react with APTES-modified ZnS/silica nanocable. Biotin could be efficiently attached silica shell with little change in the electrical characteristics of nanocables. The binding of avidin-biotin with low dissociation constant would be utilized for specific recognition. Conductance-time measurement shows that the conductance of biotin-modified nanocable increases rapidly and considerably to a constant value upon addition of the avidin solution and that this conductance value is remained even after the addition of BSA solution

In summary, we have also demonstrated the nanocable FET devices for the sensitive, label-free, real-time, selective, and electrical detection of protein using avidin-biotin system. This work presents the potential of core-shell-nanowire-based FETs for biological sensing using FIB nanofabrication and biontinylation.


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Related papers

Presentation: Poster at E-MRS Fall Meeting 2007, Acta Materialia Gold Medal Workshop, by Jr-Hau He
See On-line Journal of E-MRS Fall Meeting 2007

Submitted: 2007-05-14 13:29
Revised:   2009-06-07 00:44