A study of Laser Irradiation Influence on the Stable of Polyelectrolyte Micro- and Nanocapsules B. V. Parakhonskiy 1,2 and T. V. Bukreeva 1 1 Shubnikov Institute of Crystallography, Russian Academy of Sciences, Leninskiy pr. 59, Moscow, 119333 Russia. 2 Moscow State University, Leninskie gory, Moscow, 119992 Russia. Abstract. Laser radiation was used for permeability increase up to destroy of polyelectrolyte capsules. Silver and gold nanoparticles was synthesized and incorporated into capsule shells to attain the sensitivity of microcapsules to laser radiation. Lasers of different power and wavelength were used. The sensitivity of nanocomposite shell to laser radiation can be controlled by nanoparticles concentration. Microcapsules were prepared using different templates. We compared the results of the influence of laser irradiation on them. Introduction Polymeric nano- and microcapsules are of particular interest for a number of applications due to their high potential for encapsulation of a wide variety of compounds. These items could be useful in the areas as diverse as biology, chemistry, synthesis and catalysis. 1, 2 . Now, nano- and microcapsule systems have the highest potential in the pharmaceutical industry since many different requirements have to be fulfilled: time, position and concentration. In some cases, for drug delivery the capsule’s activation under specific internal or external actions is necessary. Nowadays, research on the use of microwave or laser radiation for these purposes is being intensively pursued; however, the task regarding microcapsules remains unsolved. Recently, it has been proposed to solve this problem with the use of polyelectrolyte capsules whose walls involve metal nanoparticles 3, 4 . The technique proposed a few years ago for producing polyelectrolyte shells on colloidal particles of a different nature is one of the most promising tools for fabricating microcapsules 5–7 . According to this technique, multilayer shells a few nanometers in thickness are prepared on the surface of spherical particles (templates), whose sizes vary from several hundred nanometers to tens of micrometers, through the sequential adsorption of oppositely charged polyelectrolyte macromolecules. In this case, templates are prepared from latex, silicon dioxide, calcium carbonate, and magnesium carbonate particles, erythrocytes, and other objects. Then, cores are removed, as a rule, through dissolution 8, 9 . As results stable hollow microcapsule are formed. Capsules permeability can be varied at the preparation stage (through variation of the material and thickness of walls and the template material) and after formation of the microcapsule (through variation of the pH or the salt composition of the subphase, addition of organic solvents, and heating). These microcapsules can be used as microcontainers and microreactors 10–12 . The advantages of polyelectrolyte capsules over other similar systems are their monodisperse size distribution, the simplicity of controlling their permeability, and the easiness of changing and a wide variety of wall materials. Shells of these microcapsules can be modified by introducing different materials, functional molecules, and nanoparticles. Metal nanoparticles or organic dyes absorbing laser radiation can be used as shell components. Laser irradiation of the capsule can lead to its deformation or destruction 3 . This method for remote release of the encapsulated material can be used for inducing the drug action in particular places of an organism, for example, in cancer cells. In this case, the capsule walls protect the encapsulated material against the environment during delivery of the drug and contain initiators of its release. Unlike microwave irradiation, laser light is local in character - an important feature in medical applications. In the present work, we have preparated laser-sensitive polyelectrolyte microcapsules by incorporating gold nanoparticles into polyelectrolyte shells and investigated the distribution of nanoparticles in a polymer matrix. WDS'07 Proceedings of Contributed Papers, Part III, 118–122, 2007. ISBN 978-80-7378-025-8 © MATFYZPRESS 118