Diamond biocompatible coatings for medical implants

New carbon (diamond-like) nanocomposite coatings deposited from a C60 ionic beam can be used as a wear-resistant protective coating for implants. It was found that these coatings enhance resistance to тelectrochemical corrosion processes due to a shift of the material’s electrode potential to a zone of positive values. They also promote a complex of reparative, adaptative and compensatory reorganization that accelerates the healing processes in the vicinity of the implant

Features of medical implant passivation using anodic oxide films

The passivation ability of metals from groups IV and V of the Periodic Table is considered. Anodic treatment is able to neutralize the increase of metal hardening when comminuting grains to nanometre sizes. The deposition of metal oxide film coatings on a cobalt–chromium alloy surface results in substantial passivation of its surface and prevents cobalt and chromium accumulation in bone tissues. The decrease of surface activity of titanium implants can be achieved both by cleaning the surface during vacuum annealing before oxidation and by the increase of the anodic oxide film thickness, which limits mass and charge transfer through the implant surface. Recommended titanium implant treatment regimens are vacuum annealing at 650 °C and anodic oxidation to attain an oxide thickness less or equal to 300 nm

Stimulation of calcium phosphate crystal formation by implant surfaces with electret properties

Oxide coatings with electret properties are investigated. The possibility of stimulation of the formation of calcium phosphate sediments near the electroactive surface is discussed. The exposure of implants with such coatings to solutions imitating blood plasma showed their high efficiency of biointegration due to activation of an exchange processes in living tissues by a negative superficial charge. The revealed effect amplifies with the growth of the thickness of the anodic oxide film

Properties of magnetron hydroxyapatite coatings deposited on oxidized substrates

Hydroxyapatite (HA) coating were formed on oxidized niobium surfaces by the highfrequency magnetron sputtering method using hydroxyapatite and tricalcium phosphate targets. The structure, substructure and mechanical properties of the Nb–Nb2O5–HA system were investigated by X-ray diffraction, atomic force microscopy and nanoindentation and the stress state was assessed. The synthesized hydroxyapatite film had the following characteristics: thermal expansion coefficient 10–5 K–1; modulus of elasticity 120 GPa; adhesive strength not less than 0.45 kg/mm2; density 2900 kg/m3. The stress magnitude in the metal oxide substrate was from 11 to 14 MPa after hydroxyapatite film deposition

A novel concept for the manufacture of individual sapphire-metallic hip joint endoprostheses.

At the present time, artificial joints made with metallic, ceramic, metal-polymeric or ceramicpolymeric friction pairs substituting for the natural biomechanic articulations "head of the hip joint-acetabulum" are widely used for endoprosthetic operations on hip joints. Experience gained in the course of more than 2000 operations has shown that along with the advantageous properties of modern endoprosthetic constructions made of metal, ceramics and polymers, they have certain drawbacks. Among them are insufficient biological inertness and susceptibility to excessive wear of the friction pair components. In addition, as a result of wear of the hinge friction pair, toxic and oncologically dangerous products of degradation accumulate in the different organs and tissues. This in turn results in severe complications and demands correspondingly complicated corrective intervention, often leading to worse disability than that which the original operation was designed to cure. The aim of the study reported here was the development and clinical validation of a highly effective and long-lived hip joint endoprosthesis with a sapphire head whose wear capacity is superior to all others. The endoprosthesis consists of a metallic pedicle, a dismountable articulation (metallic necklayer of supramolecular polyethylene-sapphire head) and an acetabular cup. The endoprostheses with the sapphire head proved themselves positively in clinical trials and are considered to be highly promising for future applications

ОСОБЛИВОСТІ ПРЕГРАВІДАРНОЇ ПІДГОТОВКИ ЖІНОК РІЗНИХ НАЦІОНАЛЬНОСТЕЙ

The aim of the study – to make a differential approach to preconception preparation and management of pregnancy in women of different nationalities.Materials and methods. There were examined 120 women of reproductive age: Slavonic (group I), Vietnamese (group II), Chinese (group III), Arabic (group IV). We studied the medical history of physical, marital, and gynecological anamnesis. The level of folic acid, cyanocobalamin, common vitamin D were determined.Results and discussion. The Ukrainian women had cardio-vascular diseases in 63.3 %, metabolic and endocrine disorders – 46.7 %, the pathology of the gastrointestinal tract – 36.7 %. Anemia took place in 66.7 % of Vietnamese women, 70.0 % – Arabian countries, the disease of the urinary excretory system were in 26.7 % and 40.0 % of patients correspondingly. More than 50 % (53.3 %) of women of the I group had a history of childbirth, 65.3 % – Arabic nationality, 50.0 % – Chinese, 33.3 % – Vietnamese. Medical abortions were noted in 30.0 % of Russian women, 6.7 % – Chinese women. Spontaneous abortion in women of Vietnamese nationality made 26.7 %, infertility – 23.3 %. Secondary amenorrhea was 6.7 %, oligomenorrhea – 16.7 %, while, insufficiency of the luteal phase – in 16.7 % of the Vietnamese women. Low levels of folic acid in blood examined ranged from 26.7 to 53.5 %, cyanocobalamin – from 3.4 to 16.7 %, vitamin D – from 33.3 to 53.3 % of cases. The most expressive abnormal parameters identified in women of group II and group III.Conclusions. Preconception preparation and management algorithm for pregnant women of different nationalities must be based on the individual characteristics of the organism. When planning a pregnancy the level of folic acid, cyanocobalamin, vitamin D should be determined in the blood of women for the purpose of early diagnosis of subclinical vitamin deficiency and possible prevention of gestational complications. Women with low levels of folate, cyanocobalamin, vitamin D in the blood before pregnancy should be examined in the I and II half of pregnancy for the purpose of timely correction.Цель исследования – сформировать дифференциальный подход к прегравидарной подготовке и ведению беременности у женщин разных национальностей.Материалы и методы. Обследовано 120 женщин репродуктивного возраста разных национальностей: славянской (группа І), вьетнамской (группа II), китайской (группа III), арабской (группа IV). Изучали анамнестические данные соматического, семейного, акушерско-гинекологического анамнеза. Определяли содержание фолиевой кислоты, цианокобаламина, витамина D общего.Результаты исследования и их обсуждение. У наших соотечественниц заболевания сердечно-сосудистой системы выявлены у 63,3  %, обменно-эндокринные нарушения – у 46,7  %, патология желудочно-кишечного тракта – у 36,7  %. Анемией страдали 66,7  % вьетнамок, 70,0  % женщин из арабских стран, заболевания мочевыделительной системы были у 26,7 и 40,0  % пациенток соответственно. Более 50  % (53,3  %) женщин группы І имели в анамнезе роды, 65,3  % – арабской национальности, 50,0  % – китайской, 33,3  % – вьетнамской. Медицинские аборты отметили 30,0  % отечественных женщин, 6,7  % – китаянок. Спонтанные аборты у женщин вьетнамской национальности составили 26,7  %, бесплодие – 23,3  %. У женщин вьетнамской национальности вторичная аменорея составила 6,7  %, олигоменорея – в 16,7  %, при этом недостаточность лютеиновой фазы – 16,7  %. Низкие уровни фолиевой кислоты в крови обследованных достигали от 26,7 до 53,5  %, цианокобаламина – от 3,4 до 16,7  %, витамина D – от 33,3 до 53,3  % случаев. Наиболее выразительные отклонения от показателей нормы выявлены у женщин группы ІІ и группы ІІІ.Выводы. Прегравидарная подготовка и алгоритм ведения беременных разных национальностей должны базироваться на индивидуальных особенностях их организма. При планировании беременности следует определять в крови женщин содержание фолиевой кислоты, цианокобаламина, витамина D с целью ранней диагностики субклинического гиповитаминоза и проведения профилактики возможных гестационных осложнений. У женщин с низкими уровнями содержания фолиевой кислоты, цианокобаламина, витамина D в крови до беременности целесообразно контролировать их уровни в первой и во второй половине беременности с целью своевременной коррекции. Мета дослідження – сформувати диференційний підхід щодо прегравідарної підготовки та ведення вагітності у жінок різних національностей.Матеріали та методи. Обстежено 120 жінок репродуктивного віку різних національностей: слов’янської (група І), в’єтнамської (група ІІ), китайської (група ІІІ), арабської (група ІV). Вивчали анамнестичні дані соматичного, сімейного, акушерсько-гінекологічного анамнезу. Визначали вміст фолієвої кислоти, ціанокобаламіну, вітаміну D загального.Результати дослідження та їх обговорення. У вітчизняних жінок захворювання серцево-судинної системи виявлено у 63,3  %, обмінно-ендокринні порушення – у 46,7  %, патологію шлунково-кишкового тракту – у 36,7  %. Від анемії страждали 66,7  % в’єтнамок, 70,0  % досліджуваних із арабських країн, захворювання сечовидільної системи були у 26,7 і 40,0  % пацієнток відповідно. В анамнезі мали пологи 53,3  % співвітчизниць, 63,3  % арабської, 50,0  % китайської і 33,3  % в’єтнамської національності. Медичні аборти були у 30,0  % вітчизняних жінок, у 6,7  % – китаянок. Спонтанні аборти у жінок в’єтнамської національності становили 26,7  %, безплідність – 23,3  %. У жінок в’єтнамської національності вторинна аменорея виявлена у 6,7  %, олігоменорея – у 16,7  %, при цьому недостатність лютеїнової фази – у 16,7  %. Низькі рівні фолієвої кислоти у крові обстежуваних становили від 26,7 до 53,5  %, ціанокобаламіну – від 3,4 до 16,7  %, вітаміну D – від 33,3 до 53,3  % випадків. Найбільш виразні відхилення від показників норми виявлено у жінок групи ІІ і групи ІІІ.Висновки. Прегравідарна підготовка й алгоритм ведення вагітних різних національностей має базуватися на індивідуальних особливостях їх організму. При плануванні вагітності слід визначати вміст фолієвої кислоти, ціанокобаламіну, вітаміну D у крові жінок з метою ранньої діагностики субклінічного гіповітамінозу та проведення профілактики можливих гестаційних ускладнень. У жінок із низьким вмістом фолієвої кислоти, ціанокобаламіну, вітаміну D у крові до вагітності доцільно контролювати їх рівень у першій і другій половині вагітності з метою своєчасної корекції.

The application of niobium and tantalum oxides for implant surface passivation.

Despite the advantages of ceramics, with their high corrosion stability in vivo, most medical implant constructions are still made from metals [1]. To increase the corrosion stability of metals, different coatings are applied to the implant surfaces, typically such coatings are the oxides of the metals in the implants [2]. For an oxide film to have protective properties it must satisfy the following requirements: • to be unbroken and pore-free; • to have good adhesion with the metal; • to have a thermal expansion constant near to the value for the metal; • to be chemically inert in different environments; • to be hard and have minimal wear under load. The oxides of metals such as Al, Ti, Zr, Nb and Ta satisfy all these properties to some degree [3–5]. Indeed, some of these metal oxides are used in medicine independently without a metal substrate, such as implant constructions from sapphire (a single-crystal modification of Al2O3) [6, 7]. Titanium is the most widely used material for medical implant manufacture [8]. Its chemical passivity is provided by the oxide film (TiO2), covering the entire free surface; a result of titanium contact with air. But titanium is unable to satisfy all the requirements necessary for an implant material because of its insufficient corrosion stability [9–11]. The application of combined implants consisting of a metal base and a ceramic coating also does not give a complete solution to the problem, because of the low adhesion strength and fragility of ceramic coatings [12, 13]

Chitosan–hydroxyapatite composite biomaterials made by a one step co-precipitation method: preparation, characterization and in vivo tests

A series of biocompatible chitosan/hydroxyapatite composites has been synthesized in an aqueous medium from chitosan solution and soluble precursor salts by a one-step coprecipitation method. The composite materials were produced in dense and porous variants. XRD and IR studies have shown that the apatite crystals in the composites have structural characteristics similar to those of crystals in biogenic apatite. A study of in vivo behaviour of the materials was carried out. Cylindrical rods made of the chitosan/ hydroxyapatite composite material were implanted into the tibial bones of rats. After 5, 10, 15 and 24 days of implantation, histological and histo-morphometric analyses of decalcified specimens were undertaken to evaluate their biocompatibility and the possibility to apply them in bone tissue engineering. The calcified specimens were examined by scanning electron microscopy combined with X-ray microanalysis to compare the elemental composition and morphological characteristics of the implant and the bone during integration. Porous specimens were osteoconducting and were replaced in vivo by newly formed bone tissue

Influence of implant surface modification on integration with bone tissue

Problems connected with the improvement of medical implant fixation in bone tissue are addressed by the formation of a highly developed surface and by the activation of the implant surface with an electret coating. The realization of such surface modifications is expedient for implants manufactured from tantalum or niobium or finished by coatings made from these metals, as they are chemically more inert than titanium. The techniques have been tested on animals followed by histological and mechanical analysis