Nanocomposites and nanomaterials

Photoacoustic investigation of dyes and carbon nanoparticles diffusion in agarose hydrogel 
Alekseev O.M., Andrusenko D.А.,·Burbelo R.M., Vasylyuk S.V., 
Kuzmich А.G.
Taras Shevchenko National University of Kyiv, 64/13, Volodymyrska Street, Kyiv 01601, Ukraine 
E-mail: kuzmich@univ.kiev.ua ; agkuzmich@gmail.com 

The development of methods for nondestructive control of nanoparticles spatial distribution, as well as their diffusion, is very important for use in analytical chemistry, pharmacology, biology and medicine [1]. To develop a methodological basis in the field of theranostics, it is expected to use phantom objects based on agarose hydrogels [2]. The study of the kinetics of changes in the spatial distribution of carbon nanoparticles in biological tissues has a special significance for applied purposes. Among the experimental methods for diffusion processes monitoring, optical methods predominate in the geometry of light passing through the  sempl. The application of these methods in medicine is rather difficult, especially in the "in situ" option.
In contrast to the standard optical methods, in this paper methods based on the photoacoustic (PA) effect are used to determine the spatial distribution of carbon nanoparticles. These methods are sensitive to the part of the radiation absorbed by the substance and they allow us to reinstate the spatial distribution function and the concentration of absorbing particles lengthwise the radiation propagation direction.
In the context of this work, PA methods are used to study the spatial distribution of nanoparticles in phantom objects based on gel. Model objects based on gels with a given spatial distribution of nanoparticles are scanned by optical radiation along the surface of the sample. The measured parameters of the PA response are compared with the spatial distribution regions of the nanoparticles in the model. Measurements of the PA response kinetics in diffusion processes of dye and carbon nanoparticles in model objects have been carried out. The dependence of the PA response parameters on the type of diffusing substance and its diffusion velocity is considered 

1.	Tan S., Dai H. and Wu J.. Optical investigation of diffusion of levofloxacin mesylate in agarose hydrogel // J. Biomedical Optics, 2009, - 14 (5), P. 050503. 
2.	Dabbagh, A., Abdullah, B. J. J., Ramasindarum, C., & Abu Kasim, N. H. Tissue-Mimicking Gel Phantoms for Thermal Therapy Studies // Ultrasonic Imaging, 2014, - 36(4), P.291–316