Electrospinning is a perspective method widely suggested for use in bioengineering applications, but the variability in currently available data and equipment necessitates additional research to ascertain the desirable methodology. In this study, we aimed to describe the effects of electrospinning technique alterations on the structural and mechanical properties of (1,7)-polyoxepan-2-one (poly-ε-caprolactone, PCL) scaffolds, such as circumferential and longitudinal stress/strain curves, in comparison with corresponding properties of fresh rat aorta samples. Scaffolds manufactured under different electrospinning modes were analyzed and evaluated using scanning electronic microscopy as well as uniaxial longitudinal and circumferential tensile tests. Fiber diameter was shown to be the most crucial characteristic of the scaffold, correlating with its mechanical properties.

Electrospun tissue-engineered grafts made of biodegradable materials have become a perspective search field in terms of vascular replacement, and more research is required to describe their in vivo transformation. This study aimed to give a detailed observation of hemodynamic and structural properties of electrospun, monolayered poly-ε-caprolactone (PCL) grafts in an in vivo experiment using a rat aorta replacement model at 10, 30, 60 and 90 implantation days. It was shown using ultrasound diagnostic and X-ray tomography that PCL grafts maintain patency throughout the entire follow-up period, without stenosis or thrombosis. Vascular compliance, assessed by the resistance index (RI), remains at the stable level from the 10th to the 90th day. A histological study using hematoxylin-eosin (H&E), von Kossa and Russell–Movat pentachrome staining demonstrated the dynamics of tissue response to the implant. By the 10th day, an endothelial monolayer was forming on the graft luminal surface, followed by the gradual growth and compaction of the neointima up to the 90th day. The intense inflammatory cellular reaction observed on the 10th day in the thickness of the scaffold was changed by the fibroblast and myofibroblast penetration by the 30th day. The cellularity maximum was reached on the 60th day, but by the 90th day the cellularity significantly (p = 0.02) decreased. From the 60th day, in some samples, the calcium phosphate depositions were revealed at the scaffold-neointima interface. Scanning electron microscopy showed that the scaffolds retained their fibrillar structure up to the 90th day. Thus, we have shown that the advantages of PCL scaffolds are excellent endothelialization and good surgical outcome. The disadvantages include their slow biodegradation, ineffective cellularization, and risks for mineralization and intimal hyperplasia.

The cytocompatibility of titanium oxides (TiO₂) and oxynitrides (N-TiO₂, TiO_xN_y) thin films depends heavily on the surface topography. Considering that the initial relief of the substrate and the coating are summed up in the final topography of the surface, it can be expected that the same sputtering modes result in different surface topography if the substrate differs. Here, we investigated the problem by examining 16 groups of samples differing in surface topography; 8 of them were hand-abraded and 8 were machine-polished. Magnetron sputtering was performed in a reaction gas medium with various N₂:O₂ ratios and bias voltages. Abraded and polished uncoated samples served as controls. The surfaces were studied using atomic force microscopy (AFM). The cytocompatibility of coatings was evaluated in terms of cytotoxicity, adhesion, viability, and NO production. It has been shown that the cytocompatibility of thin films largely depends on the surface nanostructure. Both excessively low and excessively high density of peaks, high and low kurtosis of height distribution (S_ku), and low rates of mean summit curvature (S_sc) have a negative effect. Optimal cytocompatibility was demonstrated by abraded surface with a TiO_xN_y thin film sputtered at N₂:O₂ = 1:1 and U_b = 0 V. The nanopeaks of this surface had a maximum height, a density of about 0.5 per 1 µm², S_ku from 4 to 5, and an S_sc greater than 0.6. We believe that the excessive sharpness of surface nanostructures formed during magnetron sputtering of TiO₂ and N-TiO₂ films, especially at a high density of these structures, prevents both adhesion of endothelial cells, and their further proliferation and functioning. This effect is apparently due to damage to the cell membrane. At low height, kurtosis, and peak density, the main factor affecting the cell/surface interface is inefficient cell adhesion.

Carbon nanotubes (CNTs) are used in applications ranging from electrical engineering to medical device manufacturing. It is well known that the addition of nanotubes can influence the mechanical properties of various industrial materials, including plastics. Electrospinning is a popular method for fabricating nanomaterials, widely suggested for polymer scaffold manufacturing. In this study, we aimed to describe the influence of single-walled carbon nanotube (SWCNT) suspensions on polymeric poured films and electrospun scaffolds and to investigate their structural and mechanical properties obtained from various compositions. To obtain films and electrospun scaffolds of 8 mm diameter, we used poly-ε-caprolactone (PCL) and poly(cyclohexene carbonate) (PCHC) solutions containing several mass fractions of SWCNT. The samples were characterized using tensile tests, atomic force and scanning electronic microscopy (AFM and SEM). All the studied SWCNT concentrations were shown to decrease the extensibility and strength of electrospun scaffolds, so SWCNT use was considered unsuitable for this technique. The 0.01% mass fraction of SWCNT in PCL films increased the polymer strength, while fractions of 0.03% and more significantly decreased the polymer strength and extensibility compared to the undoped polymer. The PHCH polymeric films showed a similar behavior with an extremum at 0.02% concentration for strength at break.

ЦЕЛЬ Определение типов морфологии выходного отдела правого желудочка и легочной артерии с помощью трехмерной печати с выявлением факторов риска для каждой морфологической модели. МАТЕРИАЛ И МЕТОДЫ В данное ретроспективное исследование было включено 350 пациентов педиатрической группы (от 7 до 18 лет), которым было выполнено формирование пути оттока из правого желудочка в легочную артерию в ФГБУ «НМИЦ им. акад. Е.Н. Мешалкина» с ноября 2011 г. по апрель 2022 г. РЕЗУЛЬТАТЫ Первый тип встречался у 54 (15,5%) пациентов. Фактором риска для морфологии «конусного типа» являлся ксенокондуит Contegra, который в 22,3 раза увеличивал шанс дистального стеноза (отношение шансов (ОШ) 22,3, 95% ДИ 4,8; 78, p=0,01). Второй тип встречался у 24 (6,8%) пациентов. Фактором риска для морфологии «грушевидного типа» являлся легочный гомографт, который в 2,3 раза увеличивал шанс дилатации ствола (ОШ 2,3, 95% ДИ 1,4; 8,6, p=0,034). Третий тип встречался у 87 (24,8%) пациентов. Фактором риска для морфологии типа «песочных часов» являлся ксеноперикардиальный кондуит, который в 5,1 раза увеличивал шанс проксимального стеноза (ОШ 5,1, 95% ДИ 1,8; 12,7, p=0,001). Четвертый тип встречался у 51 (14,6%) пациента. Фактором риска для морфологии типа «обратного конуса» являлась трансаннулярная пластика с моностворкой, которая в 1,2 раза увеличивала шанс мышечного стеноза (ОШ 1,2, 95% ДИ 1,1; 1,9, p=0,04). Пятый тип встречался у 21 (6%) пациента. Фактором риска для морфологии «мешотчатого типа» был ксеноперикардиальный кондуит, содержащий свиной аортальный корень, который в 2,2 раза увеличивал шанс аневризм (ОШ 2,2, 95% ДИ 1,5; 3,7, p=0,035). Шестой тип встречался у 113 (32,3%) пациентов. Нормальная конфигурация чаще всего встречалась после трансаннулярной пластики без моностворки (ОШ 1,8, 95% ДИ 1,3; 2,5, p=0,045) и имплантации легочного аллографта (ОШ 3,1, 95% ДИ 2,3; 8,9, p=0,001). ВЫВОД Трехмерный анализ морфологии выходного отдела правого желудочка и легочной артерии полезен для выбора тактики лечения и минимизации осложнений, связанных с имплантацией кондуита или транскатетерного клапана.