The 3rd Workshop on Biological Applications of Plasma/Photon Processing
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Promising future of atmospheric cold plasma in medical field
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| Ryuji Mori | ||
| Shimane Univ. | ||
| Adtec Plasma Tech. Co. (Hukuyama, Japan) has developed an instrument of
atmospheric cold plasma for clinical trials. The plasma has medically applicable
clean, simple and multipurpose characteristics. Clinical problems often
arise on the surface of organs. Wound healing and fracture union are caused
by the attachment of exposed surface. Troublesome adhesion occurs on the
tissue surface. A majority of cancer develops on such surface as membrane.
Various technologies, laser and ultrasound for example, are already in
use for medical treatment; however, the plasma has more advantages than
those because it affects only the surface without adverse effects in depth. Yet, there are huge barriers to clinical application in Japan: medical professionals seeking after European and American technologies, the government who cannot approve new instruments, and the exclusive market. We should establish a new strategy to introduce Japanese technologies into the medical field in expectation of the global upheaval of the field arriving in a decade. |
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Clinical application of high power lasers in dentistry
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| Hiroyasu Yamaguch | ||
| Tsurumi Univ. | ||
| Recently, a variety of high power lasers are used in dentistry, for example,
diode (805nm, Nd: YAG, Er: YAG (2940nm) and carbon dioxide laser (10,600nm).
Each has a set range of parameters and specifications. Emission wavelength,
power, repetition rate, energy density and delivery all affect interaction
with dental soft and hard tissue. The different wavelengths have different absorption coefficients by the varied composition of human tissue. Laser-tissue interaction are depend upon both the laser parameters and used and the dental tissue. These laser devices are applied for diagnosis, caries prevention, caries removal and cavity preparation, endodontic therapy, periodontal therapy, soft tissue surgery, bone tissue surgery, photodynamic therapy, low level laser effects, and control of pain. Operators should limit their use of dental lasers within specific indications for use. It reports on indications and the clinical procedures of these laser treatments in this presentation. |
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Ultrashort Pulsed Laser Interactions with Living Biological Samples |
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| Nicholas Smith | ||
| Osaka Univ. | ||
| Laser irradiation has provided researchers with a means to remotely modify,
dissect, and optically trap biological tissue, whole cells, or subcellular
regions of interest. In particular, for near-infrared wavelengths and sub-picosecond
pulsed lasers, multiphoton absorption and related ionization physics provides
an optical method of nanodissection with inherent sterility, localized
interactions, and deep penetration in biological samples. By tightly focusing
the laser beam using high NA optics, the photon density localization in
space and time can yield multiphoton and avalanche ionization that can
generate transient plasma within the focal zone. This talk will discuss
some of the interactions that occur when these highly nonlinear effects
are induced in living cells, and the related biological responses that
follow the laser effects. |
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Model biological membranes on solid substrates
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| Kenichi Morigaki | ||
| Advanced industrial Science and Technology(AIST) | ||
| Biological membranes have numeral vital functions in cells such as signal
transduction and immunological responses. Understanding and manipulating
their functions at the molecular level is, therefore, essential in a wide
range of biomedical applications. However, due to their complex structures,
composed of lipid bilayer membranes and associated proteins, details of
the physicochemical mechanisms are not easily available from studying living
cells. As an alternative approach, model cellular membranes have a long
history of development, and they have provided numerous important insights
into the structure and functions of the biological membranes. Especially,
substrate supported planar lipid bilayers have been recently studied extensively
as versatile model membrane systems. We would like to review their unique
features and our strategies to generate micro-patterned lipid membranes
on solid substrate from fluid and polymerized phospholipid bilayers. Brief
accounts on the possibilities for biomedical applications will also be
given. |
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Sterilization of microorganisms by plasma
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| Hideharu Shintani | ||
| Chuo Univ. | ||
| Several papers on plasma sterilization to microorganisms have been published so far. Most of those data were attained using biological indicators (BIs) with clump formation. The penetration depth of plasma was quite shallow at around 100 nm, so clump formation on BIs may cause tailing phenomena and result in unreproducible data. Tailing phenomena can be observed if the sterilants cannot be penetrated satisfactory. To avoid clump formation, even distribution of spores on BIs must be indispensable. The inactivation mechanisms of microorganisms by plasma are not necessary clarified yet. Several factors associated with mechanisms such as radical exposure, heating, etching phenomenon, UV irradiation and so on are discussing. All are not always clarified yet. Plasma sterilization is quite useful to attain material and functional compatibility with sterility assurance due to the shallow penetration. In addition, to satisfy GMP (Good Manufacturing Practice) requirement, toxins from microorganisms and prion must be inactivated in success. In this presentation, these were discussed. |
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Polymeric Nanoparticles for Cancer Diagnosis and Therapy
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| Motoi Oishi, Yukio Nagasaki | ||
| Tsukuba Univ. | ||
| We described here novel approach to the preparation of smart (therapy and diagnosis) polymeric nanoparticles based on the pH-responsive PEGylated nanogels composed of cross-linked polyamine core and tethered PEG chains. The pH-responsive PEGylated nanogels showed significant volume-phase transition in response to the extracellular pH (7-6.5) of tumor environment as well as endosomal pH (6.5-5.5). In particular, pH-responsive PEGylated nanogels containing 19F compounds showed remarkable on-off regulation of 19F MR signals in response to the extracellular pH of tumor environment, demonstrating the utility of these nanogels as tumor specific smart 19F MRI probes. Additionally, doxorubicin (DOX)-loaded pH-responsive PEGylated nanogels showed the significant antitumor activity against the human hepatoma HuH-7 cells due to the subsequent release of DOX from the nanogel in response to the endosomal pH. Thus, pH-sensitive PEGylated nanogels can be utilized as a smart nanodevice for cancer diagnosis and therapy. | ||
Free radical formation in water during plasma processing in liquids
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| Atsushi Tani | ||
| Osaka Univ.. | ||
| Free radicals formed in water during atmospheric-pressure plasma processing
with a low-frequency (LF) power supply have been investigated by electron
spin resonance (ESR). A spin-trapping compound, CYPMPO is used to trap
unstable free radicals such as hydroxyl radicals (OH·) and superoxide anion
radicals (O2-·) generated in the solution by plasma exposure. Pure helium
plasma exposure to the solution gives no ESR signals. However the plasma
exposure to the solution in a helium and oxygen mixed atmosphere results
in ESR signals of OH· and O2-· adducts. The ambient gas significantly influences
radical formation in the plasma processing in liquids. |
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