25aC01
Plasma-Functionalized CNT using Atmospheric Pressure Plasma Jet for theDevelopment of CNT-based Amperometric Biosensor
Tomy Abuzairi1,2, Mitsuru Okada3, Nji R. Poespawati2, Retno Wigajatri2, Masaaki Nagatsu1,3
1

Graduate School of Science and Technology, Shizuoka Univ., Hamamatsu, 432-8561, Japan2
Department of Electrical Engineering, Universitas Indonesia, Depok 16424, Indonesia
3
Graduate School of Engineering, Shizuoka Univ., Hamamatsu, 432-8561, Japan
E-mail: tmnagat@ipc.shizuoka.ac.jp

1. Introduction
Carbon nanotubes (CNTs) have many greatinterests for sensitive detection of biomolecules
because of their high surface area, good electricalproperties and high biomolecules recognition
capability [1]. Successful realization of biosensors
based on CNTs requires proper control of theirfunctionalization and surface immobilization.
Comparedto the conventional chemicalfunctionalization treatments, plasma treatments
have the advantages, such as low temperature andlittle damaging effects [2]. Among the plasma
treatments, atmospheric pressure plasma treatment
has attracted many researchers. In this work, an
atmospheric pressure plasma jet (APPJ) technique
is developed to functionalize amino moieties on
CNT microarray selectively. The design of thebiosensor based on CNT, such as amperometric
type biosensor was also studied. Biomolecules
immobilization onto plasma-functionalized CNT
was conducted by using biotin-avidin system and E.
coli to assess the feasibility of CNT as a biosensor.
2. Experimental
The fabrication of CNT microarray typebiosensor was performed by electron beamlithography for patterning microarray typebiosensor and thermal plasma chemical vapor
deposition method for growing the CNT. Thefabrication method of CNT microarray has beenreported in detail elsewhere [3]. An APPJ was
utilized to functionalize amino groups onto CNT.
Plasma discharge was produced in the glass tube
under the high voltage square-wave pulses. To
immobilize biomolecules selectively, we employedbiotin-avidin system and antibody-antigen reactionof E. coli.
3. Results and Discussion
The mechanism of the surface functionalization
and biomolecules immobilization of CNT is shownin Fig.1. The surface functionalization was carriedout by applied two-stage plasma treatment: (1)pre-treatment by using He discharge gas with -500
V dc biasing and (2) post-treatment by using a

mixture of helium and ammonia without bias. The
Dangling bonds were created by ion bobmardment
during pre-treatment process to ease amino group
introduction onto CNT in the post-treatment [4].
The biomolecules immobilization was simulated bybiotin-avidin and E. coli immobilization. The
confirmation of the avidin-biotin and E. coli
immobilization was evaluated by chemical
derivatization with the fluorescent dye which can bevisualized by fluorescent microscope.

Fig.1. Mechanism of the biomolecules immobilization
onto plasma-functionalized CNT.

4. Conclusion
We demonstrated functionalization of the CNT
microarray by using an APPJ technique and studied
the immobilization of biomolecules onto CNT. To
immobilize biomolecules selectively, we employedbiotin-avidin system and antibody-antigen reactionof E. coli. The successful functionalization using
APPJ and simulating biomolecules immobilization
onto CNT are valuable for development ofamperometric biosensor.
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[2] F. Pourfayaz, Y. Mortazavi, A. Khodadadi, S.H.
Jafari, et al.: Appl. Surf. Sci. 295 (2014) 69.
[3] T. Matsuda, M. Mesko, A. Ogino, M. Nagatsu: Diam.
Relat. Mater. 17 (2008) 773.
[4] T. Abuzairi, M. Okada, N.R. Poespawati, R.W.
Purnamaningsih, M. Nagatsu: Carbon 89 (2015) 208.