Physicochemical and biological analysis of composite biomaterials containing hydroxyapatite for biological applications.

Bone tissue regeneration is one of the main areas of tissue engineering. A particularly important aspect is the development of new innovative composite materials intended for bone tissue engineering and/or bone substitution. In this article, the synthesis and characterization of ceramic-polymer composites based on polyvinylpyrrolidone, poly(vinyl alcohol) and hydroxyapatite (HAp) have been presented. The first part of the work deals with the synthesis and characterization of the ceramic phase. It was demonstrated that the obtained calcium phosphate is characterized by a heterogeneity and porosity indicating simultaneously its large specific surface area. Additionally, in the wound healing test, it was shown that the obtained powder supports the regeneration of L929 cells. Next, HAp-containing composite materials were obtained in the waste-free photopolymerization process and characterized in detail. It was proved that the obtained composites were characterized by sorption properties and stability during 12-day incubation in simulated physiological liquids. Importantly, the obtained composites showed no cytotoxic effect against the L929 murine fibroblasts - the cell viability was 94.5%. Then, confocal microscopy allowed to observe that murine fibroblasts effectively colonized the surface of the obtained polymer-ceramic composites, covering the entire surface of the biomaterial. Thus, the obtained results confirm the high potential of the obtained composites in the application of bone tissue regenerative medicine.

Three Component Composite Scaffolds Based on PCL, Hydroxyapatite, and L-Lysine Obtained in TIPS-SL: Bioactive Material for Bone Tissue Engineering.

In this research, we describe the properties of three-component composite foam scaffolds based on poly(ε-caprolactone) (PCL) as a matrix and hydroxyapatite whiskers (HAP) and L-Lysine as fillers (PCL/HAP/Lys with wt% ratio 50/48/2). The scaffolds were prepared using a thermally induced phase separation technique supported by salt leaching (TIPS-SL). All materials were precisely characterized: porosity, density, water uptake, wettability, DSC, and TGA measurements and compression tests were carried out. The microstructure of the obtained scaffolds was analyzed via SEM. It was found that the PCL/HAP/Lys scaffold has a 45% higher Young's modulus and better wettability compared to the PCL/HAP system. At the same time, the porosity of the system was ~90%. The osteoblast hFOB 1.19 cell response was also investigated in osteogenic conditions (39 °C) and the cytokine release profile of interleukin (IL)-1ß, IL-6, and tumor necrosis factor (TNF)-α was determined. Modification of PCL scaffolds with HAP and L-Lysine significantly improved the proliferation of pre-osteoblasts cultured on such materials.

Preparation, Characterization, and Biocompatibility Assessment of Polymer-Ceramic Composites Loaded with Salvia officinalis Extract.

In the present work, hydroxyapatite-polymer materials were developed. The preparation, as well as characterization of the ceramic-polymer composites based on polyvinylpyrrolidone, sodium alginate, and gelatin were described. The system was enriched with the addition of common sage extract (Salvia officinalis). The antioxidant potential of sage aqueous extract and total polyphenol content was determined. The antioxidant capacity and total phenolic content of extract were equal to 86.06 ± 0.49% and 16.21 ± 0.58 mg gallic acid equivalents per gram of dry weight, respectively. Incubation studies in selected biological liquids were carried out to determine the biomineralization capacity on the surface of the composites and to examine the kinetics of release of the active substances from within the material. As a result of the incubation, a gradual release of the extract over time from the polymer matrix was observed; moreover, the appearance of new apatite layers on the composite surface was recorded as early as after 14 days, which was also confirmed by energy-dispersive X-ray spectroscopy (EDS) microanalysis. The composites were analyzed with Fourier transform infrared spectroscopy (FTIR) spectroscopy, and the morphology was recorded by scanning electron microscope (SEM) imaging. The in vitro biological studies allowed their cytotoxic effect on the reference L929 fibroblasts to be excluded. Further analysis of the biomaterials showed that enrichment with polyphenols does not support the adhesion of L929 cells to the surface of the material. However, the addition of these natural components stimulates human monocytes that constitute the first step of tissue regeneration.

PGS/HAp Microporous Composite Scaffold Obtained in the TIPS-TCL-SL Method: An Innovation for Bone Tissue Engineering.

In this research, we synthesize and characterize poly(glycerol sebacate) pre-polymer (pPGS) (1H NMR, FTiR, GPC, and TGA). Nano-hydroxyapatite (HAp) is synthesized using the wet precipitation method. Next, the materials are used to prepare a PGS-based composite with a 25 wt.% addition of HAp. Microporous composites are formed by means of thermally induced phase separation (TIPS) followed by thermal cross-linking (TCL) and salt leaching (SL). The manufactured microporous materials (PGS and PGS/HAp) are then subjected to imaging by means of SEM and µCT for the porous structure characterization. DSC, TGA, and water contact angle measurements are used for further evaluation of the materials. To assess the cytocompatibility and biological potential of PGS-based composites, preosteoblasts and differentiated hFOB 1.19 osteoblasts are employed as in vitro models. Apart from the cytocompatibility, the scaffolds supported cell adhesion and were readily populated by the hFOB1.19 preosteoblasts. HAp-facilitated scaffolds displayed osteoconductive properties, supporting the terminal differentiation of osteoblasts as indicated by the production of alkaline phosphatase, osteocalcin and osteopontin. Notably, the PGS/HAp scaffolds induced the production of significant amounts of osteoclastogenic cytokines: IL-1ß, IL-6 and TNF-α, which induced scaffold remodeling and promoted the reconstruction of bone tissue. Initial biocompatibility tests showed no signs of adverse effects of PGS-based scaffolds toward adult BALB/c mice.

Ruthenium Dendrimers against Human Lymphoblastic Leukemia 1301 Cells.

Ruthenium atoms located in the surfaces of carbosilane dendrimers markedly increase their anti-tumor properties. Carbosilane dendrimers have been widely studied as carriers of drugs and genes owing to such characteristic features as monodispersity, stability, and multivalence. The presence of ruthenium in the dendrimer structure enhances their successful use in anti-cancer therapy. In this paper, the activity of dendrimers of generation 1 and 2 against 1301 cells was evaluated using Transmission Electron Microscopy, comet assay and Real Time PCR techniques. Additionally, the level of reactive oxygen species (ROS) and changes of mitochondrial potential values were assessed. The results of the present study show that ruthenium dendrimers significantly decrease the viability of leukemia cells (1301) but show low toxicity to non-cancer cells (peripheral blood mononuclear cells-PBMCs). The in vitro test results indicate that the dendrimers injure the 1301 leukemia cells via the apoptosis pathway.

Generation Dependent Effects and Entrance to Mitochondria of Hybrid Dendrimers on Normal and Cancer Neuronal Cells In Vitro.

Dendrimers as drug carriers can be utilized for drugs and siRNA delivery in central nervous system (CNS) disorders, including various types of cancers, such as neuroblastomas and gliomas. They have also been considered as drugs per se, for example as anti-Alzheimer's disease (AD), anti-cancer, anti-prion or anti-inflammatory agents. Since the influence of carbosilane-viologen-phosphorus dendrimers (SMT1 and SMT2) on the basic cellular processes of nerve cells had not been investigated, we examined the impact of two generations of these hybrid macromolecules on two murine cell lines-cancer cell line N2a (mouse neuroblastoma) and normal immortalized cell line mHippoE-18 (embryonic mouse hippocampal cell line). We examined alterations in cellular responses including the activity of mitochondrial dehydrogenases, the generation of reactive oxygen species (ROS), changes in mitochondrial membrane potential, and morphological modifications and fractions of apoptotic and dead cells. Our results show that both dendrimers at low concentrations affected the cancer cell line more than the normal one. Also, generation-dependent effects were found: the highest generation induced greater cytotoxic effects and morphological modifications. The most promising is that the changes in mitochondrial membrane potential and transmission electron microscopy (TEM) images indicate that dendrimer SMT1 can reach mitochondria. Thus, SMT1 and SMT2 seem to have potential as nanocarriers to mitochondria or anti-cancer drugs per se in CNS disorders.

Ruthenium dendrimers against acute promyelocytic leukemia: in vitro studies on HL-60 cells.

Coordination of ruthenium arene fragments on carbosilane dendrimers' surface greatly increases their antitumor properties. Newly synthetized ruthenium dendrimers are water-soluble, monodisperse and stable. Since carbosilane dendrimers are good carriers of drugs and genes, the presence of ruthenium in their structure makes them promising candidates for new drug delivery systems with improved antitumor potential. Carbosilane ruthenium dendrimers are more toxic to cancer cells than normal cells. Results of several in vitro studies applied here indicate that carbosilane ruthenium dendrimers induce apoptosis in promyelocytic leukemia HL-60 cells.

Effect of Photobiomodulation Therapy on the Increase of Viability and Proliferation of Human Mesenchymal Stem Cells.

BACKGROUND AND OBJECTIVES: We have investigated how low intensity laser irradiation emitted by a multiwave-locked system (MLS M1) affects the viability and proliferation of human bone marrow mesenchymal stem cells (MSCs) depending on the parameters of the irradiation. STUDY DESIGN/MATERIALS AND METHODS: Cells isolated surgically from the femoral bone during surgery were identified by flow cytometry and cell differentiation assays. For irradiation, two wavelengths (808 and 905 nm) with the following parameters were used: power density 195, 230, and 318 mW/cm 2 , doses of energy 3, 10, and 20 J (energy density 0.93-6.27 J/cm 2 ), and in continuous (CW) or pulsed emission (PE) (frequencies 1,000 and 2,000 Hz). RESULTS: There were statistically significant increases of cell viability and proliferation after irradiation at 3 J (CW; 1,000 Hz), 10 J (1,000 Hz), and 20 J (2,000 Hz). CONCLUSIONS: Irradiation with the MLS M1 system can be used in vitro to modulate MSCs in preparation for therapeutic applications. This will assist in designing further studies to optimize the radiation parameters and elucidate the molecular mechanisms of action of the radiation. Lasers Surg. Med. © 2019 Wiley Periodicals, Inc.

Ruthenium dendrimers as carriers for anticancer siRNA.

Dendrimers, which are considered as one of the most promising tools in the field of nanobiotechnology due to their structural organization, showed a great potential in gene therapy, drug delivery, medical imaging and as antimicrobial and antiviral agents. This article is devoted to study interactions between new carbosilane-based metallodendrimers containing ruthenium and anti-cancer small interfering RNA (siRNA). Formation of complexes between anti-cancer siRNAs and Ru-based carbosilane dendrimers was evaluated by transmission electron microscopy, circular dichroism and fluorescence. The zeta-potential and the size of dendriplexes were determined by dynamic light scattering. The internalization of dendriplexes were estimated using HL-60 cells. Results show that ruthenium dendrimers associated with anticancer siRNA have the ability to deliver siRNA as non-viral vectors into the cancer cells. Moreover, dendrimers can protect siRNA against nuclease degradation. Nevertheless, further research need to be performed to examine the therapeutic potential of ruthenium dendrimers as well as dendrimers complexed with siRNA and anticancer drugs towards cancer cells.

Carbosilane dendrimers inhibit α-synuclein fibrillation and prevent cells from rotenone-induced damage.

This study investigates the role of carbosilane dendrimers in fibrillation of α-synuclein and prevention of the mouse hippocampal cell (mHippoE-18) from rotenone-induced damage. Examining the interaction between carbosilane dendrimers and α-synuclein, we found that the dendrimers inhibit fibril formation. We also investigated cell viability, the production of reactive oxygen species (ROS), and mitochondrial membrane potential. mHippoE-18 cells were preincubated with carbosilane dendrimers before rotenone was added. All the dendrimers possess potential protection activity. Preincubation with dendrimers contributed to: increased viability, higher mitochondrial membrane potential, and reduced ROS level in cells. The probable mechanism of cell protection lies in the ability of dendrimers to capture rotenone by encapsulating or binding to its surface groups. The fact that dendrimers have prevention potential is important in the search for new pharmacological strategies against neurodegenerative disorders.

In vitro PAMAM, phosphorus and viologen-phosphorus dendrimers prevent rotenone-induced cell damage.

We have investigated whether polyamidoamine (PAMAM), phosphorus (pd) and viologen-phosphorus (vpd) dendrimers can prevent damage to embryonic mouse hippocampal cells (mHippoE-18) caused by rotenone, which is used as a pesticide, insecticide, and as a nonselective piscicide, that works by interfering with the electron transport chain in mitochondria. Several basic aspects, such as cell viability, production of reactive oxygen species and changes in mitochondrial transmembrane potential, were analyzed. mHippoE-18 cells were treated with these structurally different dendrimers at 0.1µM. A 1h incubation with dendrimers was followed by the addition of rotenone at 1µM, and a further 24h incubation. PAMAM, phosphorus and viologen-phosphorus dendrimers all increased cell viability (reduced cell death-data need to be compared with untreated controls). A lower level of reactive oxygen species and a favorable effect on mitochondrial system were found with PAMAM and viologen-phosphorus dendrimers. These results indicate reduced toxicity in the presence of dendrimers.

[The role of proteins in neurodegenerative disease]. / Rola bialek w chorobach neurodegeneracyjnych.

 All neurodegenerative diseases are related to pathology and accumulation of proteins. Proteins are basic structural and functional components of each cell and their functions are associated with their amino acid composition and spatial structure. The proper functioning of protein is necessary for the proper operation of the body system. In the case of disorders of proteins' spatial structure, the development of pathological processes may occur. Accumulation of abnormal proteins is toxic to nerve cells and causes neurodegeneration. Different disorders are characterized by abnormalities of various proteins. This type of neurodegenerative diseases includes Parkinson's disease, tauopathies, Alzheimer's disease, and prion diseases. Parkinson's disease is characterized by toxicity of α-synuclein. The pathology of tau protein is specific for tauopathies, prion protein for prion diseases. In the case of Alzheimer's disease it is ß-amyloid. All proteins responsible for the pathology are present in the physiological state in the organism. Damage to the area of the brain covered by the pathological process and the clinical symptoms are characteristic for a particular type of disease. Detailed knowledge of the mechanisms of the disease can be an important element in the development of effective ways of treatment.