The expanding application of three-dimensional matrices with complex surface topographies in regenerative medicine requires new methods to visualize and analyze the evolving elastic properties of tissue-engineered constructs (TECs) during maturation. In this study, scanning impulse acoustic microscopy (SIAM) was employed for the non-invasive investigation of non-woven matrices based on PLLA and its composites with chitosan. This technique was used to determine the speed of sound, integral attenuation, and spectral characteristics within the samples. The data obtained through acoustic microscopy were compared with the results from tensile testing, gel permeation chromatography, differential scanning calorimetry, scanning electron microscopy, and CCK-8 assays. The findings demonstrate that SIAM exhibits high sensitivity to alterations in the TEC’s composition, including the presence of functionalizing additives, embedded cells, and the subsequent processes of cell proliferation and extracellular matrix synthesis, as well as to changes in its geometric structure. Consequently, this methodology can be recommended as a powerful and non-destructive tool for the comprehensive monitoring of TECs throughout their in vitro maturation period.

The work presents the results of testing nonwoven fibrous matrices based on poly-L-lactide modified with biopolymers (chitosan and collagen) under in situ stretching in a scanning electron microscope (SEM) chamber operating in the environmental mode. Matrix stress-strain curves and SEM images are obtained simultaneously during uniaxial stretching of the matrices until rupture. The change in the mechanical characteristics of the matrices during degradation is studied depending on the time of their incubation in the culture medium.

The adhesion, proliferation, differentiation, and other types of interaction of a cell culture with synthetic biocompatible matrices completely depend on the type of cells, as well as on the structure, filling, and surface of the matrix itself. The results of studying the proliferation of HEK293T cells on polylactide matrices of various architectures are presented. An estimate of the rate of cell proliferation is obtained for oriented and nonoriented spongy and nonwoven fibrous matrices, as well as composite polylactide matrices with collagen and chitosan.

The architecture and mechanical properties of synthetic biocompatible scaffolds used in modern tissue engineering are the most important characteristics in the manufacture of medical implants, and the evolution of their mechanical properties during degradation is of particular interest. This paper presents the results of in situ mechanical tests in a scanning-electron-microscope chamber of spongy oriented and nonoriented polymer matrices of various compositions. The stress-strain curves for the matrices under uniaxial compression are obtained, and the mechanical properties of the materials are analyzed depending on their morphological features, modification with biopolymers, and degree of degradation. The results of mechanical tests are compared with images obtained in a scanning electron microscope at different stages of compression.

The adhesive properties of scaffolds, which primarily depend on the chemical and structural features of their surface, play an important role in the tissue engineering. The cell adhesion of dissociated primary neuronal culture to isotropic and anisotropic nonwoven and sponge polylactide scaffolds was studied by fluorescence and environmental scanning electron microscopy. Neurons extracted from neonatal mouse brain showed improved adhesion on all types of scaffolds after the plasma treatment. The most pronounced effect was observed for non-oriented scaffolds.

Адгезивные свойства матриксов, преимущественно зависящие от химических и структурных особенностей их поверхности, играют важнейшую роль в тканевой инженерии. С помощью флуоресцентной и растровой электронной микроскопии в режиме окружающей среды исследована адгезия клеток диссоциированной нейрональной культуры на изотропных и анизотропных нетканых и губчатых матриксах из полилактида. Нейроны, полученные из головного мозга новорожденных мышей, демонстрировали улучшенную адгезию на матриксах всех типов после обработки плазмой, при этом наиболее выраженный эффект наблюдался на неориентированных матриксах.

The structural and mechanical features of synthetic matrices are examined using the developed in situ mechanical testing setup in a scanning-electron-microscope chamber. The mechanical behavior is correlated with direct visualization of the structural changes occurring during the deformation of oriented and nonoriented sponges and nonwoven fiber polylactide-based materials, which allows a detailed characterization of the structural deformation processes in these materials.

The effect of primary amino acid sequence in recombinant spidroins on their spatial organization is crucial for the fabrication of artificial fibers and fibrous materials. This study focuses on the rheological properties of aqueous and alcoholic solutions of recombinant analogs of natural spidroins (rS1/9 and rS2/12), as well as the structure of their films and nanofibrous materials. Non-Newtonian flow behavior of aqueous solutions of these proteins was observed at certain concentrations in contrast to their solutions in hexafluoroisopropanol. The secondary structure of recombinant spidroins was addressed by IR spectroscopy, whereas their self-organization in various solvents was studied by AFM and cryo-TEM. The influence of the solvent on the structure and properties of the films and nanofibrous materials produced by electrospinning has been established.

A production technology for conductive materials with different morphologies is developed: flat (films) and porous (sponges) composites suitable for use as the anode of a biofuel cell. Chitosan is used as a polymer matrix, and carbon-black particles with an average size of aggregates of 17 μm act as a conductive component. The morphological, electrically conductive, and mechanical characteristics of the composites are studied. Based on the functional characteristics, the optimum concentration of the filler in the composite materials for their use as the electrode of a microbial biofuel cell is 5 wt %.

Minimal interference with historical material and maximum preservation is one of the basic principles of the scientific restoration and conservation of monuments of historical and cultural heritage. The creation of nanoscale and microscale inorganic coatings is a promising way to protect limestone and marble cultural heritage objects. We conducted a laboratory testing of a method for stimulating biogenic mineral formation on the surface of limestone-masonry samples from the medieval cave town on the Eski-Kermen plateau (Crimea, Russia). The results showed the formation of a layer of crystallites of 0.4 to 1.3 µm on the surface of the limestone, an increase in the average strength values of the samples by 28% from 12.3 ± 2.8 to 15.8 ± 2.6 MPa, a 42% increase in the specific surface area of limestone, an 86% increase in salt attack resistance, and preservation of the capillary water-absorption level. The obtained results show the potential of using biogenic mineral formation for the conservation and restoration of limestone.

Highly porous polymer materials have been studied a lot for applications in biotechnology and biomedicine, because of their high surface area and percolated pore structure. Varying processing conditions, in this study, can tune the morphology, mechanical, and physicochemical characteristics of the materials. In the present work, cross-linked poly(vinyl alcohol)-based freeze-dried sponges linked by glutaraldehyde are studied. The current study analyzes the influence of cooling speed on the sponge's morphology and mechanical properties. Complex analysis of the tests carried out shows agreement in morphology, surface area, equilibrium degree of swelling, and mechanical properties of the sponges with dependence on the amount of cross-linking agent and freezing conditions.

To follow the structural reorganization of spidroin during its spinning, the rheological behavior of low-concentration solution of recombinant spidroins rS1/9 and rS2/12 is studied on different stages of separation, purification, and lyophilization. It is shown that spidroin solutions with concentration of 1 mg mL(-1) appear to be structured liquids with yield stress around value 0.2 Pa. Distribution of hydrodynamic radii of spidroins reveals two peaks due to presence of single particles and aggregates both. Their ability for spidroin transformation from micellar to fibrillar structure under shear stress is demonstrated. Studying rheological behavior of recombinant spidroin solutions and their supramolecular organization is necessary to select the optimal spinning parameters to produce fibrous materials with required physicochemical properties.

The effects of plasma treatment on the surface roughness and hydrophility of polymer materials used as biodegradable scaffolds (polylactide films, sponges, and nonwoven fibrous sheets) have been studied. Two methods have been used for quantitative estimation of changes: three-dimensional reconstruction of the scaffold surfaces using scanning electron microscopy (SEM) and BET physical adsorption analysis. Proceeding from the experimental results, it is established that plasma treatment forms nano- and micropits on the sample surface and thus increases its hydrophility (moreover, the surface morphology can be varied by changing the treatment duration). It is shown that plasma treatment is an efficient method for controlled increase in the roughness of polymer materials, which can lead to enhancement of adhesion and proliferation of cells.

Одним из наиболее прочных природных материалов является паутина. Прочность ее нитей может достигать 1.3–1.5 ГПа, что сопоставимо с прочностью стали. Энергия ее разрушения достигает огромных значений 194–283 МДж/м3 , поэтому текстиль на основе паучьих нитей может найти применение в изготовлении композиционных элементов для летательных аппаратов и автомобилей. Волокна паука обладают высокой биосовместимостью, поддерживают жизнеспособность клеток и обладают антибактериальными свойствами и не вызывают иммунного ответа. Таким образом, они могут быть использованы для изготовления трехмерных пористых клеточных каркасов для целей тканевой инженерии. К несомненным достоинствам волокон паука относится то, что они не плавятся. Поэтому текстильные изделия из паучьего шелка можно использовать для изготовления армейской экипировки. К сожалению, производить паучий шелк с помощью массового разведения пауков невозможно. В связи с этим ведется разработка его синтетических аналогов с помощью технологии рекомбинантной ДНК. С целью создания отечественной технологии изготовления искусственного шелкового волокна и медицинских материалов в данном обзоре приводятся основные работы в области исследования реологических свойств растворов спидроина (основной материал паутины) и фиброина шелка, показывающие, как структурные превращения спидроина, индуцированные изменением pH, содержанием соли и напряжением сдвига, определяют его способность к самоорганизации в водных растворах. Приводится анализ важнейших работ в области мокрого, сухо-мокрого формования и электроформования волокон, а также сравнение механических свойств волокон рекомбинантного спидроина с соответствующими показателями природных волокон паука. Значительные успехи, достигнутые в последнее время в этой области, позволяют перейти к созданию волокнистых материалов нового поколения.

A spiderweb is one of the strongest natural materials. The strength of its filaments can reach 1.3–1.5 GPa, which is comparable to the strength of steel. Its toughness reaches enormous values of 194–283 MJ/m3; therefore, textiles based on spider yarns may be promising in the production of composite materials for aircraft and automobiles. Spiderweb fibers have high biocompatibility and antibacterial properties, support cell viability, and do not cause an immune response. Thus, they can be used for manufacturing three-dimensional porous cell scaffolds for tissue engineering purposes. The undoubted advantages of spiderweb fibers include the fact that they do not melt. Therefore, textile products made of spider silk can be used for the production of military equipment. Unfortunately, mass production of spider silk using breeding of spiders is not possible. In this regard, development of synthetic analogues using recombinant DNA technology is of current interest. In order to create the technology for manufacturing artificial silk fiber and medical materials, this review presents the main findings in studying the rheological properties of solutions of spidroin (the main web material) and silk fibroin. These findings demonstrated how structural transformations of spidroin are induced by a change in the pH, salt content, and shear stress, and determine its ability for self-organization in aqueous solutions. An analysis of the most important studies of wet, dry–wet spinning, and electrospinning of fibers is presented, as is a comparison of the mechanical properties of the fibers of recombinant spidroin and natural spider fibers. Significant recent successes in this area allow us to advance toward the creation of a new generation of fibrous materials.