In this work, we investigate a hybrid system based on a biocompatible polymer matrix loaded with a fluorescent photodynamic dye zinc phthalocyanine as a platform with high photodynamic activity in the first biological window and the ability to visualize the biodistribution of the system in vivo. In this regard, biocompatible polyelectrolyte carriers of submicron size were used, which enable efficient immobilization of low-molecular-weight dyes and carry out photodynamic therapy without uncontrolled release of the photodynamic agent. Since the thickness of the polyelectrolyte shell of the carrier do not exceed several tens of nanometers, and the lifetime of singlet oxygen enable motion over distances of up to several microns, the photodynamic activity of the immobilized agent can be observed even without the release of the photodynamic agent from the polyelectrolyte carrier, thus making the carrier itself a photodynamic agent. The ability to flexibly vary the composition of the polyelectrolyte shell of the carriers allows it to include functional organic and inorganic components, which makes it possible to provide the function of visualizing the biodistribution of the delivery system in vivo during circulation in the body. The system described in this work will provide additional functionalization of the carriers, such as the ability to visualization of the biodistribution of submicron polymer carriers loaded with photodynamic agents in laboratory mice in vivo which has been investigated in this work. These results open up a venue for the therapy based on the principles of "image-guided therapy".
One of the most effective ways of targeted drug delivery is the intravenous injection of carriers. However, to prevent undesirable side effects it is necessary to develop microencapsulation drug delivery systems that satisfy following requirements: biocompatibility, non-cytotoxity, biodegradability, colloidal stability in different medium solutions. In case of polymeric microcapsules, aggregation is a crucial and challenging question for biomedical applications that has not been studied well yet. We investigated polymeric microcapsules behavior in PBS, human plasma, and human blood in time. Aggregation degree was measured after 1, 10, 30, and 60 minutes of incubation in a stationary state. As a result, dynamics of capsules aggregation was shown for each medium.
Microcapsules with and without magnetite nanoparticles incorporated in the polyelectrolyte shell were prepared. The effect of external electric field on the nanocomposite polyelectrolyte microcapsules containing magnetite nanoparticles in the shell was studied in this work as a function of the electric field strength. Effect of electric fields on polyelectrolyte microcapsules and the control over integrity of polyelectrolyte microcapsules with and without inorganic nanoparticles by constant electric field has been investigated. Beads effect, aggregation and deformations of nanocomposite microcapsule shell in response to electric field were observed by confocal laser scanning microscopy (CLSM). Thus, a new approach for effect on the nanocomposite microcapsule, including opening microcapsule shell by an electric field, was demonstrated. These results can be used for creation of new systems for drug delivery systems with controllable release by external electric field.
The formation of a monolayer and its structure depend on many factors. One of the least studied factors is the influence of the electric field. In this regard, the purpose of this study is to investigate the influence of the direction and magnitude of the electric field on the properties of monolayer, formed on the surface of water. The experiments have revealed: the electric field exerts a significant influence on the formation of monolayers, in particular, during liquid phase formation. The second part of the isotherm (corresponding liquid phase) were significantly stretched. We explain the liquid phase extension by the fact of the charge increasing (and change pH) of the surface region. To confirm this assumption also we made computer modelling of process monolayer formation.
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