| AVS 59th Annual International Symposium and Exhibition | |
| Plasma Science and Technology | Monday Sessions |
| Session PS+BI-MoA |
| Session: | Applications of (Multiphase) Atmospheric Plasmas (including Medicine and Biological Applications) |
| Presenter: | T. Kaneko, Tohoku University, Japan |
| Authors: | T. Kaneko, Tohoku University, Japan Q. Chen, Tohoku University, Japan R. Hatakeyama, Tohoku University, Japan |
| Correspondent: | Click to Email |
Recently, multiphase plasmas, particularly gas-liquid phases plasmas have attracted much attention as fundamental and application researches [1], because the non-equilibrium plasmas in gas phase can produce the various kinds of chemically active ions and radicals which react with nano- and bio-materials stably existing in liquid. As one of the promising applications of the gas-liquid interfacial discharge plasmas (GLIDPs), the synthesis of various kinds of nanoparticles [2] is advantageous in that toxic reducing agents are unnecessary and the synthesis is continuous during the plasma irradiation. In addition, the GLIDPs are also used in the biomedical field, for example, the synthesis of gold nanoparticles (AuNPs) conjugated with biomolecules such as DNA. The DNA conjugated AuNPs (DNA-AuNPs) work as vectors to deliver DNA into living cells because the AuNPs can be efficiently manipulated by a light field. Furthermore, the DNA-AuNPs are attempted to be encapsulated into carbon nanotubes (CNTs) to protect the DNA from the ambient environment.
The GLIDP is generated between the bottom liquid and top metal electrodes in Ar gas (20 kPa) by applying a pulse voltage (20 kHz) to the liquid electrode. The liquid electrode consists of aqueous chloroauric acid trihydrate (HAuCl4•3H2O) (0.1 mg/ml) with DNA. A single-stranded DNA is used as the conjugated material, which consists of 30 bases of cytosine or guanine. In the synthesis of the DNA-AuNP encapsulated CNTs, double-walled carbon nanotubes (DWNTs) are adopted to be used because of their large inner diameter.
Depending on the DNA concentration, the resultant water-soluble AuNPs take on pink and purple. The different colors originate from the particle size and interparticle distance which determine the absorption wavelength of the surface plasmon resonance of the AuNPs. Interestingly, these phenomena depend on the types of DNA base, which are attributed to the difference in the binding energy of the DNA base. Therefore, we can control the size and assembly of the AuNPs by changing the DNA type and concentration [3].
In order to encapsulate the negatively charged DNA-AuNPs into the DWNTs, a positive DC voltage is applied to the DWNTs put on the substrate immersed in the GLIDP. The transmission electron microscope images of the resultant products show that the number of the DNA-AuNPs encapsulated into DWNTs increases with an increase in the positive DC voltage.
[1] T. Kaneko, K. Baba and R. Hatakeyama: J. Appl. Phys. 105, 103306 (2009).
[2] T. Kaneko, Q. Chen, T. Harada and R. Hatakeyama: Plasma Sources Sci. Technol. 20, 034014 (2011).
[3] Q. Chen, T. Kaneko, and R. Hatakeyama: Chem. Phys. Lett. 521, 113 (2012).