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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-22 1:27 |
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Conference: Bucharest University Faculty of Physics 2010 Meeting
Section: Optics, Spectroscopy, Plasma and Lasers
Title:
Laser induced modifications of phenothiazines
Authors:
Mihail Lucian Pascu(1), Viorel Nastasa(1)(2), Adriana Smarandache(1), Andra Militaru(1), Ana Martins(2), Miguel Viveiros(2), Mihai Boni(1), Ionut Relu Andrei(1), Alexandru Pascu(1), Angela Staicu(1), Joseph Molnar(3) and Leonard Amara(l)(2)
Affiliation:
(1) National Institute for Laser, Plasma and Radiation Physics, Laser Department, P.O. Box MG-36, Str. Atomistilor nr. 409, Magurele, Ilfov, Bucharest 077125, Romania.
(2) Unit of Mycobacteriology and UPMM, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisbon, Portugal
(3) Institute of Medical Microbiology and Immunobiology,University of Szeged,Dom tér 10, Szeged, H-6720,Hungary
E-mail
viorel.nastasa@inflpr.ro
Keywords:
Lasers, bioactive phenothiazines, laser induced modification of physico-chemical properties, laser induced fluorescence, laser photochemistry
Abstract:
The vast majority of drugs employed in modern medicine have their origins in the chemical manipulation of phenothiazines . Chemical manipulation of a compound for the creation of new derivatives is limited by the existing science of organic chemistry, is time consuming and the percent yield of an active product is quite small. Exposure of a phenothiazine to UV –VIS yields a product that is more biologically active than the un-exposed parent. However, because the product is highly unstable, the demonstration of increased activity is usually possible only when exposure of the phenothiazine to UV (incoherent) takes place in the presence of the biological target-example: bacteria. Moreover, because the source of incoherent UV provides a wide spectrum of wavelength, little is known of the response of a given phenothiazine to a much narrower spectrum. Lasers have been used in recent years for localized effects on tissues when the tissue and the phenothiazine are simultaneously irradiated. The difference between exposures of a phenothiazine to a UV laser versus that to incoherent UV is that a laser produces a specific wavelength with a higher energy level at the given wavelength. Because of the specificity of wavelength and beam energy provided by a laser, one would suppose that exposure of a phenothiazine to laser radiation would produce rearrangements of the molecule whose bioactivity could be studied without concurrent exposure of the biological target to the laser, that is, provided that the rearranged compound is sufficiently stable for study. Moreover, if exposure of the phenothiazine to the laser beam is conducted in the presence of a reactive compound, there is the distinct possibility that entirely new compounds can be quickly created within hours if not minutes that may be difficult, if not impossible to create via conventional chemical manipulation.The reported study examines the optical properties of three neuroleptic phenothiazines with antimicrobial activities prior to and subsequent to exposure to two different lasers singly or in sequence and evaluates the activity of the laser exposed products against a reference Staphylococcus aureus strain.
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