Scaffolds for tissue engineering

The paper presents the current trends in medicine of regenerative tissue defect caused by resection of tumors or fractures. Although it is a relatively young field of science, it creates new possibilities for the reconstruction of pathologically altered tissue with the use of three-dimensional scaffolds. Tissue engineering places particular emphasis on the type of scaffold from which they are made because of a number of requirements of medical materials including biocompatibility, mechanical strength and porosity

Hydroxyapatite/Silver Nanoparticles Powders as Antimicrobial Agent for Bone Replacements

This paper reports a superficial morphological modification of the hydroxyapatite grains obtained by in situ deposition of Ag nanoparticles on natural origin calcium phosphate powder. Ceramic material was prepared in three stage bone treatment, including hydrolysis with a lactic acid, pre-calcination, and proper calcination. Subsequently, the Ag nanoparticles were synthesized by chemical reduction of Ag+ by sodium borohydride in a solution of polyvinylpyrrolidone and in presence of hydroxyapatite. Such-prepared materials were investigated with X-ray diffraction, Fourier-transformed infrared spectroscopy, atomic absorption spectrometry and scanning electron microscopy with energy dispersive spectroscopy. Furthermore, Ca/P molar ratio was calculated and microbiological tests were performed to investigate materials antimicrobial activity. The appearance of Ag nanoparticles located on phosphate surface was confirmed by SEM analysis, and no chemical bonding with hydroxyapatite was recorded by IR and XRD techniques. Additionally, the biological assessment revealed bactericidal effect on Escherichia coli and Staphylococcus aureus, while slightly affected on Enterococcus faecalis viability. This work is licensed under a Creative Commons Attribution 4.0 International License

The effect of glycerin content in sodium alginate/poly(vinyl alcohol)- based hydrogels for wound dressing application

The impact of different amounts of glycerin, which was used in the system of sodium alginate/poly(vinyl alcohol) (SA/PVA) hydrogel materials on the properties, such as gel fraction, swelling ability, degradation in simulated body fluids, morphological analysis, and elongation tests were presented. The study shows a significant decrease in the gel fraction from 80.5 2.1% to 45.0 1.2% with the increase of glycerin content. The T5 values of the tested hydrogels were varied and range from 88.7 C to 161.5 C. The presence of glycerin in the matrices significantly decreased the thermal resistance, which was especially visible by T10 changes (273.9 to 163.5 C). The degradation tests indicate that most of the tested materials do not degrade throughout the incubation period and maintain a constant ion level after 7-day incubation. The swelling abilities in distilled water and phosphate buffer solution are approximately 200–300%. However, we noticed that these values decrease with the increase in glycerin content. All tested matrices are characterized by the maximum elongation rate at break in a range of 37.6–69.5%. The FT-IR analysis exhibits glycerin changes in hydrogel structures, which is associated with the cross-linking reaction. Additionally, cytotoxicity results indicate good adhesion properties and no toxicity towards normal human dermal fibroblasts

Synthesis and characterization of polymer-based coatings modified with bioactive ceramic and bovine serum albumin

This study involves the synthesis of hydroxyapatite and describes the preparation and characterization of polymer coatings based on poly(ethylene glycol) diacrylate and poly(ethylene glycol) and modified with bovine serum albumin and hydroxyapatite. Hydroxyapatite was obtained by wet chemical synthesis and characterized by X-ray diffraction and FTIR spectroscopy, and its Ca/P molar ratio was determined (1.69 ± 0.08). The ceramic and bovine serum albumin were used in the preparation of composite materials with the polymeric matrix. The chemical composition of coatings was characterized with FTIR spectroscopy, and their morphology was recorded with SEM imaging. Moreover, the measurements of surface roughness parameters and stereometric research were performed. The prepared coatings were subjected to in vitro studies in simulated body fluid and artificial saliva. Changes in chemical composition and morphology after immersion were examined with FTIR spectroscopy and SEM imaging. Based on the conducted research, it can be stated that applied modifiers promote the biomineralization process. The roughness analysis confirmed prepared materials were characterized by the micrometer-scale topography. The materials morphology and roughness, and the morphology of the newly formed apatite deposit, were dependent on the type of the used modifier, and the artificial fluid used in in vitro studies

Preparation and characterization of bio-hybrid hydrogel materials

In recent decades, research has focused on the development of modern hydrogel dressings due to their open porous structure, moisture retention and good mechanical strength, which ensures an optimal environment for cell migration and proliferation. Active hydrogel dressings, currently available on the market, are not endowed with additional medicinal substances. In this work the authors attempted to introduce a carrier-drug system into the hydrogel matrix to improve the wound healing process and the tissue recovery. The main goal of the research was to obtain the bio-hybrid sodium alginate/poly(vinyl alcohol)/Aloe vera (SA/PVA/AV)-based hydrogel matrices modified with the thermosensitive polymeric carrier – the active substance (hydrocortisone) system. First, thermosensitive polymeric nanocarriers were obtained, then the encapsulation was conducted, using varied amounts of hydrocortisone (25 and 50 mg) to maintain the stability of the resulting emulsions. The last stage was preparing the bio-hybrid hydrogel matrices by the chemical cross-linking method. The non-invasive dynamic light scattering (DLS) technique was employed for the analysis of the average particle size of the polymeric carriers and the carrier-drug systems. Moreover, the studies also determined the swelling behaviour and the gel fraction of the obtained bio-hybrid hydrogel matrices modified with carrier-drug systems by the infrared spectroscopy (FT-IR). The presented research results constitute a good experimental basis for further modifications, the final effect of which is assumed to be a modern bio-hybrid 3rd generation dressing

Bio-Hybrid Hydrogels Incorporated into a System of Salicylic Acid-pH/Thermosensitive Nanocarriers Intended for Cutaneous Wound-Healing Processes

In this paper, the preparation method of bio-hybrid hydrogels incorporated into a system of salicylic acid-pH/thermosensitive nanocarriers to speed up the wound-healing process was developed. This combination creates a dual drug delivery system, which releases the model hydrophobic active substance—salicylic acid—in a gradual and controlled manner for an extended time. Our research team has determined the various properties of bio-hybrid hydrogels based on their physicochemical (swelling degree, and degradation), structural (FT-IR), morphological (SEM), and mechanical (elongation tests) traits. Moreover, empty pH/thermosensitive nanocarriers and their salicylic acid-containing systems were characterized using the following methods: DLS, TG/DTG, and DSC. Additionally, salicylic acid release profiles directly from thermosensitive nanocarriers were compared to the bio-hybrid matrix. These studies were conducted in PBS (pH = 7.4) for 7 days using the USP4 method. To evaluate the antibacterial properties of the obtained materials, the inhibition of growth of Staphylococcus aureus, Escherichia coli, Candida albicans, and Aspergillus niger—as the main microorganisms responsible for human infections—were tested. The obtained results indicated that the pH/thermosensitive nanocarrier–salicylic acid system and bio-hybrid hydrogels are characterized by antibacterial activity against both S. aureus and E. coli

14-Substituted Diquinothiazines as a New Group of Anticancer Agents

A series of novel double-angularly condensed diquinothiazines with aminoalkyl, amidoalkyl, sulfonamidoalkyl, and substituted phenyl groups was designed, synthesized, and evaluated for their anticancer activity against four selected human tumor cell lines (HTC116, SH-SY5Y, A549, and H1299). The cytotoxicity of the novel diquinothiazines was investigated against BEAS-2B cells. The activities of the compounds were compared to etoposide. Among them, compounds with aminoalkyl and phenyl groups showed excellent broad-spectrum anticancer activity. The most active 14-(methylthiophenyl)diquinothiazine, 3c, showed low cytotoxicity against BEAS-2B cells and high activity against tumor cell lines HTC116, SH-SY5Y, A549, and H1299, with IC50 values of 2.3 µM, 2.7 µM, 17.2 µM, and 2.7 µM, respectively (etopiside 8.6 µM, 3.9 µM, 44.8 µM, and 0.6, respectively). Live long-term microscopic observations of cell survival using the starting molecule M0 were also performed. Flow cytometry showed the proapoptotic effects of the studied diquinothiazines. Inhibition of the cell cycle in the S phase was observed, which is associated with damage to nucleic acids and connected to DNA replication arrest