Characteristics and in vitro response of thin hydroxyapatite-titania films produced by plasma electrolytic oxidation of Ti alloys in electrolytes with particle additions

The enhancement of the biological properties of Ti by surface doping with hydroxyapatite (HA) is of great significance, especially for orthodontic applications. This study addressed the effects of HA particle size in the electrolyte suspension on the characteristics and biological properties of thin titania-based coatings produced on Ti–6Al–4V alloy by plasma electrolytic oxidation (PEO). Detailed morphological investigation of the coatings formed by a single-stage PEO process with two-step control of the electrical parameters was performed using the Minkowski functionals approach. The surface chemistry was studied by glow discharge optical emission spectroscopy and Fourier transform infrared spectroscopy, whereas mechanical properties were evaluated using scratch tests. The biological assessment included in vitro evaluation of the coating bioactivity in simulated body fluid (SBF) as well as studies of spreading, proliferation and osteoblastic differentiation of MC3T3-E1 cells. The results demonstrated that both HA micro- and nanoparticles were successfully incorporated in the coatings but had different effects on their surface morphology and elemental distributions. The micro-particles formed an irregular surface morphology featuring interpenetrated networks of fine pores and coating material, whereas the nanoparticles penetrated deeper into the coating matrix which retained major morphological features of the porous TiO2 coating. All coatings suffered cohesive failure in scratch tests, but no adhesive failure was observed; moreover doping with HA increased the coating scratch resistance. In vitro tests in SBF revealed enhanced bioactivity of both HA-doped PEO coatings; furthermore, the cell proliferation/morphometric tests showed their good biocompatibility. Fluorescence microscopy revealed a well-organised actin cytoskeleton and focal adhesions in MC3T3-E1 cells cultivated on these substrates. The cell alkaline phosphatase activity in the presence of ascorbic acid and β-glycerophosphate was significantly increased, especially in HA nanoparticle-doped coatings

Plasma-Coated Polycaprolactone Nanofibers with Covalently Bonded Platelet-Rich Plasma Enhance Adhesion and Growth of Human Fibroblasts.

Biodegradable nanofibers are extensively employed in different areas of biology and medicine, particularly in tissue engineering. The electrospun polycaprolactone (PCL) nanofibers are attracting growing interest due to their good mechanical properties and a low-cost structure similar to the extracellular matrix. However, the unmodified PCL nanofibers exhibit an inert surface, hindering cell adhesion and negatively affecting their further fate. The employment of PCL nanofibrous scaffolds for wound healing requires a certain modification of the PCL surface. In this work, the morphology of PCL nanofibers is optimized by the careful tuning of electrospinning parameters. It is shown that the modification of the PCL nanofibers with the COOH plasma polymers and the subsequent binding of NH(2) groups of protein molecules is a rather simple and technologically accessible procedure allowing the adhesion, early spreading, and growth of human fibroblasts to be boosted. The behavior of fibroblasts on the modified PCL surface was found to be very different when compared to the previously studied cultivation of mesenchymal stem cells on the PCL nanofibrous meshes. It is demonstrated by X-ray photoelectron spectroscopy (XPS) that the freeze-thawed platelet-rich plasma (PRP) immobilization can be performed via covalent and non-covalent bonding and that it does not affect biological activity. The covalently bound components of PRP considerably reduce the fibroblast apoptosis and increase the cell proliferation in comparison to the unmodified PCL nanofibers or the PCL nanofibers with non-covalent bonding of PRP. The reported research findings reveal the potential of PCL matrices for application in tissue engineering, while the plasma modification with COOH groups and their subsequent covalent binding with proteins expand this potential even further. The use of such matrices with covalently immobilized PRP for wound healing leads to prolonged biological activity of the immobilized molecules and protects these biomolecules from the aggressive media of the wound

Экспериментальная модель для исследования биологически детерминированных взаимодействий в области контакта имплантат - костная ткань

Aim: a) to develop the method for surface modification of polytetrafluoroethylene (PTFE) by applying a nanostructured metallic or ceramic coating, b) to study the possibility of using this obtained structures with different coatings as an experimental model for analysis of the fine interactions in the contact implant-tissue zone. The study demonstrates that the surface modification of PTFE by magnetron sputtering of nano-Ti and Ti-Ca-P-C-O-N leads to increased integration potential of materials. Data obtained indicate that the designed constructions can be successfully used as an experimental model for studying the interactions of implant - tissue interface elements of periimplant area.В задачи работы входило: а) разработка метода модификации поверхности политетрафторэтилена (ПТФЭ) путем нанесения наноструктурного металлического или керамического покрытия; б) исследование возможности использования полученной таким образом конструкции с различными по составу покрытиями в качестве экспериментальной модели для исследования тонких взаимодействий в области контакта имплантат - тканевые элементы периимплантационной зоны. Исследование продемонстрировало, что модификация поверхности ПТФЭ путем магнетронного напыления нанопокрытий Ti и Ti-Ca-P-C-O-N приводит к повышению интеграционного потенциала материалов. Полученные результаты свидетельствуют о том, что разработанные конструкции могут быть с успехом использованы в качестве экспериментальной модели для изучения взаимодействий в области интерфейса имплантат - тканевые элементы периимплантационной зоны

AGGREGATIVE STABILITY OF h-BN HYDROSOL IN THE PRESENCE OF NaCl

The aggregative stability of h-BN hydrosol in the presence of NaCl solution was studied by DLS and turbidimetry. NaCl was demonstrated to be indifferent with respect to hydrosol particles.The threshold concentration of NaCl below which h-BN hydrosol remain relatively stable was determined.Работа выполнена при финансовой поддержке Российского Научного Фонда (соглашение № 20–19–00120)

SYNTHESIS AND PROPERTIES OF HETEROSTRUCTURED Ag/MgO/BN CATALYSTS

Microparticles of hexagonal boron nitride with a trace Mg content were subjected to a high-temperature annealing on air. As the result formation of hexagonal-shaped surface defects decorated by MgO nanoparticles (NPs) occurred. Formation of Ag over the surfaces of the obtained substrate was conducte.Работа выполнена при финансовой поддержке Российского Научного Фонда (соглашение № 20-79-10286)

Development of Heterogeneous Nanostructures Based on Bimetallic Nanoparticles and Two-Dimensional Boron Nitride

The development of industry leads to the emergence of new, important environmental problems. This makes it necessary to develop new types of adsorbents. Important properties of such materials are their inertia, as well as the possibility of its removal from the water for further processing.Работа выполнена при финансовой поддержке Российского Научного Фонда (соглашение № 20-79-10286)