| AVS 58th Annual International Symposium and Exhibition | |
| Plasma Science and Technology Division | Monday Sessions |
| Session PS+BI-MoA |
| Session: | Multiphase (Liquid, Solid, Gas) and Biological Related Plasmas |
| Presenter: | Ting-Ying Chung, University of California, Berkeley |
| Authors: | T.-Y. Chung, University of California, Berkeley N. Ning, University of California, Berkeley J.-W. Chu, University of California, Berkeley D.B. Graves, University of California, Berkeley E. Bartis, University of Maryland, College Park J. Seog, University of Maryland, College Park G.S. Oehrlein, University of Maryland, College Park |
| Correspondent: | Click to Email |
Conventional medical instrument sterilization methods are generally ineffective in completely removing harmful biological residues [1]. Biomolecules such as proteins and other pyrogens from bacterial residues are particularly resistant to elevated temperature and are not easily removed by conventional procedures [2, 3]. For example, the presence of lipopolysaccharide (LPS) in host tissue or blood circulation could lead to a generalized sepsis syndrome including fever, hypotension, and respiratory dysfunction and may lead to multiple organ failure and death [4]. Low temperature plasma is a promising technique for sterilization/deactivation of surgical instruments or medical devices, but its effectiveness against such targets is incompletely understood [5]. In this study using a vacuum beam system, we chose lipid A, the major immune-stimulating region of LPS, as a model biomolecule to study. Lipid A consists of a β-1,6-linked D-glucosamine (GlcN) disaccharide carrying two phosphoryl groups. This structure is attached to multiple acyl chains by ester or amide linkage [6]. After vacuum ultraviolet (VUV) photon exposure, loss of CH2/CH3, C=O ester, and P=O absorption peaks were observed by ex-situ transmission Fourier transform infrared (FTIR) spectroscopy, but the C=O amide absorption peak was only mildly affected. Monitoring photolysis products from lipid A films by in-situ mass spectrometry, we observed cracking patterns similar to those of alkanes/alkenes with a carbon number ~11-13. This result suggests that VUV photons remove phosphate groups and break ester linkages leading to desorption of acyl chains. Endotoxicity of lipid A is known to be primarily determined by the number and length of acyl chains as well as the phosphorylation state and the disaccharide backbone [6]. The present results therefore indicate that plasma-generated VUV reduces the endotoxicity of lipid A, in support of the hypothesis of Rossi et al. [7]. We report the effects of VUV and radical (H, O) exposures on endotoxicity based upon chemical structural change in Lipid A. Synergism of various beams is compared with plasma exposures and corresponding molecular dynamic (MD) simulations.
[1] R. L. Baxter et al., J. Hosp. Infect. 63, 439 (2006)
[2] T. Nakata, J. Parenter. Sci. Technol. 47, 258 (1993)
[3] L. Moesby et al., Eur. J. Pharm. Sci. 26, 318 (2005)
[4] J. Cohen, Nature 420, 885 (2002)
[5] A. von Keudell et al., Plasma Process. Polym. 7, 327 (2010)
[6] C. Erridge, E. Bennett-Guerrero, and I. R. Poxton, Microbes Infect. 4, 837 (2002)
[7] F. Rossi et al., New J. Phys. 11, 115017 (2009)