Method of modifying envelopes of polyelectrolyte capsules with magnetite nanoparticles

FIELD: chemistry.

SUBSTANCE: invention relates to a method of modifying envelopes of polyelectrolyte capsules with magnetite nanoparticles. The disclosed method involves producing a container matrix in form of porous calcium carbonate microparticles, forming envelopes of polyelectrolyte capsules by successive adsorption of polyallyl amine and polystyrene sulphonate and modifying with magnetite nanoparticles on the surface of the container matrix or after dissolving the matrix through synthesis of magnetite nanoparticles via chemical condensation.

EFFECT: invention enables to obtain modified polyelectrolyte capsules, designed to deliver medicinal substances which do not harm the human body.

3 cl, 4 dwg, 1 ex

The invention relates to the field of medicine and biotechnology, and is intended for drug delivery using polyelectrolyte capsules, modified magnetic nanoparticles.

The unique properties of magnetic nanoparticles - high magnetization and magnetic anisotropy, giant magnetoresistance, abnormally large magnetocaloric effect and others [1] - led to the rapid developments in the field of synthesis of these objects and the active development of methods of their research. Of particular interest is associated with the potential use of magnetic nanoparticles in medicine and biotechnology for drug delivery [2], hyperthermia [3, 4], contrast enhancement optical tomography [5, 6], cell division [7]. The most suitable magnetic material is a biocompatible oxides, in particular iron oxide Fe3O4 - magnetite.

Delivery of drugs, including shipping address, is an urgent task of modern medicine. One of the most effective and promising ways is a drug delivery using magnetic media (magnetic delivery"). "Magnetic delivery" allows you to work on a limited, well-defined area of the body, reduces the amount of typing for functional compounds, a decrease in the concentration of drug substances the TV in places are not affected, and therefore, minimizes the side effects of the drug. For the implementation of the "magnetic" delivery connection, or covalently associated with the surface of the nanoparticles, or placed in capsules containers, modified magnetic particles. The use of magnetic containers, moreover, that leads to benefits actually "magnetic delivery, promotes the bioavailability of drugs, reducing their cytotoxicity, expands the range of applicable drugs.

A little over ten years ago to get microcontainer was proposed method of layer-by-layer adsorption of oppositely charged polyelectrolytes on the surface of colloidal particles, the so-called Layer-by-Layer [8]. This method allows to obtain a stable monodisperse capsules with nanometer-permeable membrane from a wide range of polymers, including biocompatible [9]. Due to the electrostatic adsorption in the process of forming the shell of the capsule in its composition can include nanoparticles with surface charge. In this way polyelectrolyte capsules were modified nanoparticles of gold and silver for remote opening of the shell by the action of the laser radiation [10-12]. Using electrostatic adsorption of the nanoparticles on the surface oblock the polyelectrolyte capsules also carried out the modification of such capsules magnetite nanoparticles [13]. However, for manipulating capsules by using a magnetic field of their shell must contain a large number of magnetic nanoparticles that can be obtained only by repeating the stage of adsorption particles after formation of oppositely charged polyelectrolyte layer. The alternative is obtaining nanoparticles directly on the shell of a capsule. Nanoparticles of silver and gold included in the polyelectrolyte membrane capsules using in situ synthesis, which allowed us to speed up and simplify the procedure of creation of nanocomposite capsules [14, 15].

A known method of producing microcapsules with shells from allylamine and the magnetite nanoparticles, including 1) obtaining matrix-kernel - particulate manganese carbonate; 2) creation using the method of layer-by-layer adsorption on the surface of the microparticles manganese carbonate shell, the inner layer of which consists of nitrate complex of allylamine, and the outer layer of allylamine and polystyrenesulfonate; 3) dissolution of the matrix kernel of manganese carbonate in 0.1 M HCl solution; 4) the replacement of citrate ions of the inner layer of the capsule's shell on the hydroxyl-ions-keeping system in 0.01 M NaOH solution; 5) processing of the obtained capsules solution salts of iron (II) and iron (III) to form the magnetite nanoparticles in the inner layer of capsules; 6) remove the outer layers of the capsules is from allylamine and polystyrenesulfonate in high-alkaline environment (D.G. Shchukin et al. // Angew. Chem. Int. Ed. 2003. V.42. P.4472). In the known method magnetite nanoparticles obtained by chemical condensation of magnetite in the alkaline environment of the inner layers of the capsule's shell created by the replacement of citrate ions to hydroxyl ions. Obtaining magnetic nanoparticles directly in the shell of the capsule allows on the one hand, to bring the magnetic properties, and on the other, to give greater mechanical stability compared to conventional membrane polyelectrolyte capsules.

The disadvantages of this method are:

The use of manganese carbonate as a matrix-kernel requires strict conditions for its dissolution - hydrochloric acid to pH 1.

Obtaining microcapsules modified nanoparticles of magnetite - multistage and complex, associated with the formation of polyelectrolyte membranes with different types of layers of internal and external parts, replacement ions of the inner part of the membrane, the formation of magnetite and removing the outer layers.

Magnetite particles modify only the inner part of the membrane polyelectrolyte capsules, therefore, for the effective manipulation of the capsules with the help of a magnetic field is necessary to remove the outer layers, which requires the use of high-alkaline environment.

The task underlying the present invention is proposed is giving way to obtain modified polyelectrolyte capsules, which can be used for drug delivery, which allows to overcome the mentioned drawbacks of the known method.

The technical result is to develop a simple and reliable method of obtaining modified polyelectrolyte capsules intended for drug delivery, using components that do not have harmful effects on the human body.

The task and the technical result is achieved by the fact that in modification of polyelectrolyte capsules intended for drug delivery, including the production of matrix-container, the formation of polyelectrolyte shell on the surface of the matrix container, modified polyelectrolyte membrane on the sensor surface of the container or after dissolution of the matrix; the matrix container of calcium carbonate synthesized in the form of porous microparticles. As matrix-container use porous spherical particles of calcium carbonate, obtained by draining aqueous solutions containing ions of Ca2+ and CO32-. Then on the surface of these particles perform sequential adsorption of allylamine and polystyrenesulfonate with the formation of the polyelectrolyte membrane capsules. Modification of membrane polyelectrolyte capsules carried out as follows: the solution of the chlorides of divalent or trivalent iron is poured suspension capsules with negatively charged outer layer, while mixing, gradually add the ammonia solution, kept under stirring, and then the precipitate capsules with nanoparticles separated by centrifugation and washed with water. Dissolution of the carbonate matrix is performed under the action of ethylenediaminetetraacetic acid (EDTA) in neutral conditions, which is especially important when working with many biological objects. Therefore, carbonate microparticles are particularly attractive for the formation of microcapsules biological and medical purposes.

The essence of the invention is illustrated with diagrams and photographs presented on the figures:

figure 1. The diagram of a method of obtaining polyelectrolyte capsules with modified shell;

figure 2. The image of the particles of calcium carbonate obtained by transmission electron microscopy;

figure 3. Image aqueous suspension of capsules (PAA/PSS)4/Fe3O4: before (a) and after (b) exposure of the magnet;

Fig 4. The image of the nanoparticles based on the polyelectrolyte membrane capsules obtained using transmission electron microscopy.

The scheme of operations for obtaining the modified polyelectrolyte capsules is illustrated in figure 1.

The first operation is the synthesis of microparticles, which is the core for further education on the basis of polyelectrolyte capsules. As a researcher who, as such particles were formed porous particles of calcium carbonate.

The calcium carbonate.

Synthesis of porous CaCO3 microparticles was carried out by direct mixing of solutions containing ions of Ca2+ and CO32- [16]. When it first formed amorphous precipitate of CaCO3 nanoparticles, and then to the extent of their units have growth centers of the microparticles. Experimental conditions, namely the type of salts used, their concentration, pH, temperature, mixing speed solutions and the intensity of stirring of the reaction mixture, which significantly affects the quality of the obtained particles.

The obtained microparticles of calcium carbonate consistently adsorbing the allylamine and polystyrenesulfonate by sequential incubation with stirring these particles in their water solutions.

For modification of the polyelectrolyte membrane capsules their suspension was added to a solution of the chlorides of divalent or trivalent iron, with stirring, gradually add the ammonia solution, kept under stirring, and then the precipitate capsules with nanoparticles were separated by centrifugation and washed with water.

An example implementation of the method.

Pre-formed microparticles of calcium carbonate were incubated for 15 min in a solution of allylamine hydrochloride) (PAA) while mixing on a shaker (IKA-VIBRAX-VXR, IKA, Germany). After incubation, the microparticles were washed with an aqueous solution of NaCl. Then p is bodily incubation in aqueous solution polystyrenesulfonate sodium (SAR) under the same conditions. Thus, the procedure of sequential incubation in solutions of polymers were repeated to obtain capsules with a shell composition (PAA/PSS)4. The method of transmission electron microscopy (TEM) in the sample revealed the presence of spherical particles, coated, size 2.5-4.5 µm (figure 2).

The membrane obtained polyelectrolyte capsules carried out the synthesis of the magnetite nanoparticles according to the method of Elmore [17], which represents the chemical condensation of fine-grained magnetite, which is based on the reaction:

2FeCl3+FeCl2+8NH4OH→Fe3O4↓+8NH4Cl+4H2O.

For the synthesis of nanoparticles of magnetite in situ on the surface of the polyelectrolyte capsules pre-mixed 1M solutions of floodof two - and trivalent in the ratio 1:2 and was placed in an ultrasonic bath with thermostat (Sonorex Super 10P, 35 Hz, 160/230W, Bandelin Electronics GmbH, Germany) at a temperature of 80°C prior to the acquisition of solution color of strong tea. Then this solution was added to a suspension of capsules in the nuclei of CaCO3 (1.5×10-5 and 3×10-5 mol Fe2+ and Fe3+, respectively, at 108 particles) with stirring of the reaction mixture with ultrasound and a temperature of 80°C and slowly added 28%ammonia solution before purchasing capsules dark brown, almost black color. After keeping the system at the same temperature and stirring ultrasound for 30 min the precipitate capsules with nanoparticles the mi was separated by centrifugation (ROTINA 38/38R, Hettich, Germany) and washed three times with water.

Polyelectrolyte capsules of PAA and rescue service to the magnetic field is not receptive. After conducting a chemical condensation of magnetite in suspension capsules microparticles acquired magnetic properties - they move quickly in the aquatic environment under the influence of an external magnetic field (figure 3).

In the study of nanocomposite capsules powder diffraction (synchrotron radiation Protein with two-dimensional CCD-detector Rayonix SX165, 2048×2048), it was determined that the main phase of the nanoparticles, synthesized on the membrane polyelectrolyte capsules is a magnetite. Using TEM after synthesis of magnetite on the shell nanoparticles was observed two forms (figure 4) octahedron, characteristic crystals of magnetite, with a party of 5 to 30 nm, and sterjnevye, wide, mostly 5-10 nm and a length of about 100 nm.

Thus, in situ synthesis of magnetite nanoparticles by the method of chemical condensation effectively imparts magnetic properties of polyelectrolyte capsules as a potential means of drug delivery. The way is simple, does not require the use of high temperatures and toxic compounds. The main crystalline phase of the synthesized nanoparticles is a biocompatible magnetite, which makes the proposed method modifications capsules very ne is promising for use in medicine and biotechnology.

Sources of information:

1. S. p. Gubin, Koksharov Y.A., G.B. Khomutov, etc. // USP. 2005. T. S.

2. A.S. Lubbe, C. Alexiou, C. Bergemann // J. Surg. Res. 2001. V.95. P.200.

3. Jordan, A., Scholz R, Wust P. et al. // J. Magn. Magn. Mater. 1999. V.201. P.413.

4. The Brusentsov, N.A., Brusentsov T.N., Filinov EJ // Hemat. Journe. 2007. V.41. No. 9. P.3.

5. L.X. Tiefenauer, Tschirky A., G. Kuhne, R.Y. Andres // Magn. Reson. Imaging 1996. V.14. P.391.

6. The Brusentsov, N.A., V.A. Polyanskiy, Pies Y.A., etc. // Hemat. Journe. 2010. T. No. 6. P.7.

7. Zborowski, M., Sun L., L.R. Moore et al. // J. Magn. Magn. Mater. 1999. V.194. P.224.

8. Sukhorukov G.B., E. Donath, H. Lichtenfeld et al. // Colloids Surf. A: Physicochem. Eng. Aspects. 1998. V.137. P. 253.

9. De Geest B.G., De Koker, S., G.B. Sukhorukov et al. // Soft Matter. 2009. V.5. P.282.

10. A.G. Skirtach, Dejugnat C., D. Braun et al. // Nano Lett. 2005. V.5. P.1371.

11. Angelatos A.S., Radt Century, Caruso F. // J. Phys. Chem. B. 2005. V.109. P.3071.

12. Boukreev T.V., Parahonskiy BV, Our A.G., etc. // Kristallografiya. 2006. T. No. 5. .183.

13. U.S. patent No. 6479146, IPC A61K 9/51, publ. 12.11.2002

14. A.A. Antipov, G.B. Sukhorukov, Fedutik Y.A. et al. // Langmuir. 2002. V.18. P.6687.

15. Koo H.Y., Choi W.S., Kim D.Y. // Small. 2008. V.4. P.742.

16. Volodkin D.V. Petrov, A.I., M. Prevot, G.B. Sukhorukov // Langmuir. 2004. V.20. P.3398-3406.

17. Elmore W.. // Phys. Rew. 1938. V.54. P.309.

1. Modification of membranes polyelectrolyte capsules nanoparticles of magnetite, which includes the receipt of a matrix container, the formation of the polyelectrolyte membrane capsules, modifying the magnetite particles on the sensor surface of the container or after dissolution of the matrix, distinguishing the I, as matrix-container use porous microparticles of calcium carbonate, and a polyelectrolyte membrane capsules obtained by the consecutive adsorption of allylamine and polystyrenesulfonate, modify by the synthesis of magnetite nanoparticles by the method of chemical condensation.

2. The method according to claim 1, characterized in that as the base of the container polyelectrolyte capsules-modified magnetite particles, use of porous spherical particles of calcium carbonate, obtained by draining aqueous solutions containing ions of CA²⁺and CO₃^2-.

3. The method according to claim 1, characterized in that the modification of polyelectrolyte shells of the capsules to a solution of the chlorides of divalent or trivalent iron is poured suspension of capsules on the nuclei of caso₃, with stirring, ultrasound and a temperature of 80°C. slowly add a solution of ammonia, maintain the system for 30 min in the same conditions, the sediment capsules with nanoparticles separated by centrifugation and washed with water.