Multilayer microcapsules for delivery, control and triggered release of bioactive compounds
Abstract
Developing of targeted drug delivery systems is currently a very important topic,
which can be easily judged by a great number of papers published every year.
Materials science proposes, among others, microcapsules as one of the possible
solutions to the problem. Known for more than a decade by know, microcapsules,
their properties, methods of encapsulation, release, control where under thorough
investigation by several scientific groups in the world. Despite the fact that many
factors were already studied, application of this system to drug delivery provides an
enormous amount of work yet to be done, lying across several areas of science –
biology, chemistry, physics, medicine. To be used as a technique of targeted
delivery, not only the microcapsules should meet many constraints on their physical
and chemical properties, but also the means of their control and release triggering
irradiation should be applicable and harmless to living body. This means, that
there's a lot more to do than to encapsulate the substances of interest and make
sure they stay inside the capsules.
This is why this research was devoted to investigation of stability of cargo
encapsulated to layer-by-layer microcapsules constructed on silica and CaCO3
microparticles using various shell constructions with synthetic and biodegradable
polyelectrolytes, nanoparticles, DNA, enzyme and other materials, methods of
microcapsules control by magnetic field, which can be used for navigation of the
carriers in-vivo to the place of interest and methods of release of encapsulated
substances from the microcapsules, that are friendly to living body.
The thesis starts with introduction and a literature review to help reader to get a
better understanding on the structures discussed in this work and what have
already been done in the area. These are followed by a short description of main
materials and methods used to conduct this research. Three following chapters of
experimental section describe the research itself. Chapter 4 shows feasibility of
triggered IR-laser and high-frequency ultrasound release, including intracellular
release. Reporting application of cargo using pH-sensitve dye is shown. Ultrasoundtriggered
release at parameters, close to that currently used in medical
applications, is shown to achieve up to 60% efficiency of previously reported highpower
20 kHz ultrasonic irradiation. Feasibility of laser-induced triggered release
using microcapsules functionalized photo-sensitive dyes was also shown. In Chapter
5 retention of activity of DNA and enzyme molecules upon encapsulation was
demonstrated. Activity of encapsulated substances was shown to be lower, than of
free ones, but the accessibility and kinetics of reactions can be controlled by
adjusting the construction of microcapsules. In Chapter 6 feasibility of control of
cells impregnated with microcapsules functionalized with magnetite nanoparticles
was shown at distances of up to 10 mm using usual constant magnets.
Authors
Pavlov, Anton M.Collections
- Theses [3831]