Laser beams resonant interaction with micro-droplets which have a controlled content

Abstract

The multiple resistance to treatment, acquired by bacteria and malignant tumours requires to find alternatives to the existing medicines and treatment procedures. One of them is strengthening the effects of cytostatics by modifying their molecular structures through exposure to laser radiation. A method associated with this is the generation of micro-droplets which contain medicines solutions; the droplets are vectors to transport the medicines to targets. We report, for the first time, results on the measurements of the surface tension and contact angles of the micro-droplets containing solutions of BG1120, i.e. 4,6-bis(2-N,N-dimethylaminoethylthio)-10-methylpyrido[3,2-g]quinoline and Doxorubicin, in ultra-pure water in the 10 −3–10 −6 M concentration range. The measurements of surface tension and contact angles (on hydrophobic and superhydrophobic surfaces) have shown that the BG1120 and Doxorubicin molecules distribution in the droplets is and remains homogeneous in time. The results are useful for studies on the compatibility between droplets containing medicines and the materials used for droplets instrumentation. They show that the surface tension and the contact angles of ultra-pure water droplets and of droplets containing the medicines are practically the same, within the experimental errors. The resonant interaction between the micro-droplets that contain solutions of BG1120 and Doxorubicin in ultra-pure water, and the laser radiation was, for the first time, studied. In both cases the molecules exhibited significant modifications after exposure to laser radiation (the pH remained all the time neutral), which were evidenced by measuring the UV–vis absorption and fluorescence spectra. These modifications are obtained faster in micro-droplets than in the same solutions irradiated in bulk.