V. V. Vinogradov

Leach-proof magnetic thrombolytic nanoparticles and coatings of enhanced activity

Despite the fact that magnetic thrombolytic composites is an emerging area, all known so far systems are based on the similar mechanism of action: thrombolytic enzyme releases from the magnetic carrier leaving non-active matrix, thus making the whole system active only for a limited period of time. Such systems often have very complex structure organization and composition, consisting of materials not approved for parenteral injection, making them poor candidates for real clinical trials and implementation. Here we report, for the first time, the production of thrombolytic magnetic composite material with non-releasing behavior and prolonged action. Obtained composite shows good thrombolytic activity, consists of fully biocompatible materials and could be applied as infinitely active thrombolytic coatings or magnetically-targetable thrombolytic agents.

Development of the low-temperature sol-gel synthesis of TiO2 to provide self-cleaning effect on the textile materials

This work is devoted to the development of “smart textiles” possessing high photocatalytic activity in the decomposition of organic compounds. To modify cotton fibers, the nanocrystalline TiO2 sol was used. 1,2,3,4-Butane tetracarboxylic acid was used as a spacer. Photoactive nanoparticles were formed as a result of low-temperature sol-gel synthesis, leading to the formation of titanium dioxide of anatase-brookite modification. The self-cleaning properties of the modified textile materials were estimated by the decomposition of Rhodamine B under UV irradiation.

Biocomposites for wound-healing based on sol–gel magnetite

Currently, efficient wound-healing materials are booming due to increasing health care costs and world population aging, but also because of a sharp increase in the incidence of diabetes and obesity. Exacting demands are placed upon modern wound-healing materials as these should affect all stages of healing by accelerating them. In this paper, we demonstrate for the first time that drug entrapped magnetite xerogels can be effectively used for this purpose. To prepare a healing biocomposite, we have combined four medicaments in a magnetite matrix: chlorhexidine digluconate as an antimicrobial agent, lidocaine as a painkiller, prednisolone as an anti-inflammatory agent and chymotrypsin as a necrolytic agent. Compared to the control group, the wound healing rate with a biocomposite exhibited a ∼1.5-fold increase (21 and 14 days for complete healing, respectively). Moreover application of a magnetite-based biocomposite provided strong scar size decrease. Characteristics of the magnetite matrix as well as wound-healing composite material are fully described by XRD, XPS, SEM, TEM and N2 physisorption analysis.

Plasminogen activator entrapped within injectable alumina: a novel approach to thrombolysis treatment

A major obstacle in the development of new enzyme-based thrombolytic systems is their low stability and extremely short half-life (usually, less than 2–6xa0min of circulation half-life), which requires their administration in large doses to obtain therapeutic effects, and as a consequence, inevitably leads to a significant incidence of hemorrhagic complications. Here we point to a potential solution of this problem by developing a new family of injectable composites for thrombolysis: plasminogen activator entrapped within alumina, where alumina is a pertinent drug carrier developed to prolong activity in vivo and to reduce the total administered dose of the drug necessary for the treatment, and hence its side effects.

A synergistic biocomposite for wound healing and decreasing scar size based on sol–gel alumina

The synthesis of new biocomposites exhibiting a synergistic effect is a promising step in the healing of acute and chronic wounds. In the present study we have combined four materials: chlorhexidine digluconate as a antimicrobial agent, lidocaine as a painkiller, chymotrypsin as a necrolytic agent, and sol–gel processed alumina as a carrier for the sustained delivery of drugs and as an established wound healer. Composites were synthesized and characterized for surface morphology, crystalline structure and in vitro drug release. In vivo wound healing efficacy was assessed using a full thickness excision wound model in Wistar rats. The main result, was that a marked decrease in scar size was observed because of the wound healing composite, in fact the area of the scar in the test group of rats was 2.4 times smaller than that in the control group. Wound closure analysis revealed that complete epithelialization was observed after 15 ± 1 days using the biocomposite, whereas this took 17 ± 1 days and 19 ± 1 days using the healing solution alone or pure alumina gel, respectively. It was concluded that the synergistic combination of healing drugs, with sol–gel alumina as dressing material, provides a highly attractive biomaterial for the treatment of surface wounds, burns and foot ulcers.

Synthesis of Thrombolytic Sol–Gel Coatings: Toward Drug-Entrapped Vascular Grafts

As is evident from numerous investigations, drug-eluting vascular grafts and stents have not solved the main problems associated with thrombosis and due to drug release only postpone their advance for a longer period. Here we point to a potential solution of this problem by developing thrombolytic sol-gel coatings which potentially could lead to drug-entrapped vascular grafts: urokinase-type plasminogen activator was entrapped within a porous alumina sol-gel film with a subsequent deposition on a polymer graft.

Streptokinase@alumina nanoparticles as a promising thrombolytic colloid with prolonged action

The present study is devoted to the development of a new class of thrombolytic systems - nanocolloids. A non-direct plasminogen activator, streptokinase, was entrapped in a sol-gel matrix based on boehmite nanoparticles used in medical practice as the most common vaccine adjuvant. It is shown that when the enzyme content in the composite is less than 10%, only minor release is observed, while thrombolytic properties are maintained at a relatively high level, demonstrating the prolonged effect. Based on the obtained composites, thrombolytic nanocolloids containing nanoparticles of less than 500 nm size and suitable for parenteral administration were produced. The thrombolytic properties were studied using the plasminogen activation tests, human plasma clots and a model thrombus made from a whole human blood. Based on the obtained results, the structure of the composites and the mechanism of their action are suggested.

Low-temperature approach to forming high-porous Fe(III)-TiO2 nanoparticles possessing high photoactivity

Nanodimensional Fe(III)-TiO2 crystalline particles have been obtained by the soft chemistry technique in an aqueous solution without calcination. The crystallization of the products of hydrolysis of titanium dioxide used as a precursor was carried out by boiling in the presence of acidic peptizing agents, which facilitated the temperature dehydration of hydroxo and oxo compounds. A phase of nanodimensional magnetite was used as a center of crystallization, which resulted in the doping of the crystalline lattice of TiO2 of an anatase modification. The powders and films that formed from solutions showed high photocatalytic activity under the action of visible light. According to morphological analysis, nanodimensional Fe(III)-TiO2 crystalline particles possess a narrow size distribution of pores and a high specific surface area.

Synthesis of mesoporous γ-alumina by sol–gel process and its characterization and application for sorption of Pu(IV)

Mesoporous γ-alumina samples were prepared by the sol–gel process from the boehmite sol having different template solutions. Copper doped material was also prepared from sol containing template solution along with copper nitrate. Studies were performed to understand the influence of templates on the morphology of the synthesized samples particularly with respect to specific surface area and porosity. Synthesized samples were used to study sorption of Pu(IV) from nitric acid–oxalic acid solutions. Distribution ratios (D) for Pu(IV) were determined using the γ-alumina samples with an objective to employ these for the recovery of Pu.

New approach to obtaining nanosized pseudobrookite crystals

Nanocomposites on the basis of TiO2 and Fe3O4 oxides are of interest as photocatalysts, materials for spintronics, sensorics, etc. In the present paper, a new approach is considered for obtaining pseudobrookite crystallites based on sol-gel transformations and interactions of components of a multiphase colloid system, making it possible to obtain hydroxylated crystallites of the material which are structurally identical to pseudobrookite at close to room temperatures without an annealing stage. Structural changes occurring at interactions of TiO2 and Fe3O4 nanoparticles during the synthesis are investigated by the method of dynamical light scattering. A comparison of the spectral characteristics of the nanocomposite, titania (anatase), and magnetite in visible and UV spectral ranges showed a significant shift in the nanocomposite absorption band to the visible range when compared to pure components.