Cold atmospheric plasma modification and electrical conductivity induction in gelatin/polyvinylidene fluoride nanofibers for neural tissue engineering.

BACKGROUND: This research follows some investigations through neural tissue engineering, including fabrication, surface treatment, and evaluation of novel self-stimuli conductive biocompatible and degradable nanocomposite scaffolds. METHODS: Gelatin as a biobased material and polyvinylidene fluoride (PVDF) as a mechanical, electrical, and piezoelectric improvement agent were co-electrospun. In addition, polyaniline/graphene (PAG) nanoparticles were synthesized and added to gelatin solutions in different percentages to induce electrical conductivity. After obtaining optimum PAG percentage, cold atmospheric plasma (CAP) treatment was applied over the best samples by different plasma variable parameters. Finally, the biocompatibility of the scaffolds was analyzed and approved by in vitro tests using two different PC12 and C6 cell lines. In the present study the morphology, FTIR, dynamic light scattering, mechanical properties, wettability, contact angle tests, differential scanning calorimetric, rate of degradation, conductivity, biocompatibility, gene expression, DAPI staining, and cell proliferation were investigated. RESULTS: The PAG percentage optimization results revealed fiber diameter reduction, conductivity enhancement, young's modulus improvement, hydrophilicity devaluation, water uptake decrement, and degradability reduction in electrospun nanofibers by increasing the PAG concentration. Furthermore, ATR-FTIR, FE-SEM, AFM, and contact angle tests revealed that helium CAP treatment improves scaffold characterizations for 90 s in duration time. Furthermore, the results of the MTT assay, FE-SEM, DAPI staining, and RT-PCR revealed that samples containing 2.5% w/w of PAG are the most biocompatible, and CAP treatment increases cell proliferation and improves neural gene expression in the differentiation medium. CONCLUSIONS: According to the results, the samples with the 2.5% w/w of PAG could provide a suitable matrix for neural tissue engineering in terms of physicochemical and biological.

Poly (3-hydroxybutyrate-co-3-hydroxyvalerate) improved osteogenic differentiation of the human induced pluripotent stem cells while considered as an artificial extracellular matrix.

Cocell polymers can be the best implants for replacing bone defects in patients. The pluripotent stem cells produced from the patient and the nanofibrous polymeric scaffold that can be completely degraded in the body and its produced monomers could be also usable are the best options for this implant. In this study, electrospun poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) nanofibers were fabricated and characterized and then osteogenic differentiation of the human-induced pluripotent stem cells (iPSCs) was investigated while cultured on PHBV scaffold. MTT results showed that cultured iPSCs on PHBV proliferation were increased compared to those cultured on tissue culture polystyrene (TCPS) as the control. Alkaline phosphatase (ALP) activity and calcium content were also significantly increased in iPSCs cultured on PHBV compared to the cultured on TCPS under osteogenic medium. Gene expression evaluation demonstrated that Runx2, collagen type I, ALP, osteonectin, and osteocalcin were upregulated in iPSCs cultured on PHBV scaffold in comparison with those cultured on TCPS for 2 weeks. Western blot analysis have shown that osteocalcin and osteopontin expression as two major osteogenic markers were increased in iPSCs cultured on PHBV scaffold. According to the results, nanofiber-based PHBV has a promising potential to increase osteogenic differentiation of the stem cells and iPSCs-PHBV as a cell-co-polymer construct demonstrated that has a great efficiency for use as a bone tissue engineered bioimplant.

Novel bioactive porous starch-siloxane matrix for bone regeneration: Physicochemical, mechanical, and in vitro properties.

So far, many studies have focused on biodegradable scaffolds for tissue engineering purposes. Herein, a starch-based biodegradable scaffold was fabricated by the freeze-drying method and cross-linked using a different concentration of 3-glycidoxypropyl-trimethoxysilane (GPTMS). Field emission scanning electron microscopy (FE-SEM) micrographs indicated an interconnected porous microstructure in which the porosity decreased as a function of starch and GPTMS content. Increasing the mechanical stability and decreasing absorption capacity and biodegradation ratio affected by the higher concentration of cross-linker and the changes in structure as a function of cross-linker enhancement. Moreover, the mineralization of hybrid structures in simulated body fluid was proved by FE-SEM image and X-ray diffraction analysis. Results indicated the more GPTMS in scaffolds led to more hydroxyapatite formation. The ability of the growth and proliferation of bone marrow mesenchyme stem cells on the constructs confirmed the ability of scaffolds for bone tissue engineering applications.

Graphene oxide incorporated polycaprolactone/chitosan/collagen electrospun scaffold: Enhanced osteogenic properties for bone tissue engineering.

This in vitro study aimed to evaluate the physicochemical and biological activity of the polycaprolactone/chitosan/collagen scaffolds incorporated with 0, 0.5, 3, and 6 wt% of graphene oxide (GO). Using standard tests and MG-63 cells, the characteristics of scaffolds were evaluated, and the behavior of osteoblasts were simulated, respectively. A non-significant decrease in nanofibers diameter was noted in scaffolds with a higher ratio of GO. The hydrophilicity and bioactivity of the scaffold surface, as well as cell attachment and proliferation, increased in correspondence to an increase in GO. The higher ratio of GO also improved the osteogenesis activity. GO increased the degradation rate, but it was negligible and seemed not enough to endanger stability. Modifying the scaffolds with GO did not make a significant change to the antibacterial effect.

Evaluation of cell adhesion and osteoconductivity in bone substitutes modified by polydopamine.

Bones damaged due to disease or accidents can be repaired in different ways. Tissue engineering has helped with scaffolds made of different biomaterials and various methods. Although all kinds of biomaterials can be useful, sometimes their weakness in cellular activity or osteoconductivity prevents their optimal use in the fabrication of bone scaffolds. To solve this problem, we need additional processes, such as surface modification. One of the common methods is coating with polydopamine. Polydopamine can not only cover the weakness of the scaffolds in terms of cellular properties, but it can also create or increase osteoconductivity properties. Polydopamine creates a hydrophilic layer on the surface of scaffolds due to a large number of functional groups such as amino and hydroxyl groups. This layer allows bone cells to anchor and adheres well to the surfaces. In addition, it creates a biocompatible environment for proliferation and differentiation. Besides, the polydopamine coating makes the surfaces chemically active by catechol and amine group, and as a result of their presence, osteoconductivity increases. In this mini-review, we investigated the characteristics, structure, and properties of polydopamine as a modifier of bone substitutes. Finally, we evaluated the cell adhesion and osteoconductivity of different polydopamine-modified bone scaffolds.

Comparison of the effect of argon, hydrogen, and nitrogen gases on the reduced graphene oxide-hydroxyapatite nanocomposites characteristics.

In this study, the effect of the argon, nitrogen, and hydrogen gases on the final properties of the reduced graphene oxide- hydroxyapatite nanocomposites synthesized by gas injected hydrothermal method was investigated. Four samples were synthesized, which in the first sample the pressure was controlled by volume change at a constant concentration. In subsequent samples, the pressure inside the autoclave was adjusted by the injecting gases. The initial pressure of the injected gases was 10 bar and the final pressure considered was 25 bar. The synthesized powders were consolidated at 950 °C and 2 MPa by spark plasma sintering method. The final samples were subjected to Vickers indentation analysis. The findings of this study indicate that the injection of argon, hydrogen, and nitrogen gases improved the mechanical properties of the nanocomposites. Injection of gases increased the crystallinity and particle size of hydroxyapatite, and this increase was greater for nitrogen gas than for others. Injection of these gases increased the rate of graphene oxide reduction and in this case the effect of nitrogen gas was greater than the others.

Fabrication and characterisation of super-paramagnetic responsive PLGA-gelatine-magnetite scaffolds with the unidirectional porous structure: a physicochemical, mechanical, and in vitro evaluation.

Architecture and composition of Scaffolds are influential factors in the regeneration of defects. Herein, synthesised iron oxide (magnetite) nanoparticles (MNPs) by co-precipitation technique were evenly distributed in polylactic-co-glycolic acid (PLGA)-gelatine Scaffolds. Hybrid structures were fabricated by freeze-casting method to the creation of a matrix with tunable pores. The synthesised MNPs were characterised by transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction spectroscopy, and vibrating sample magnetometer analysis. Scanning electron microscopy micrographs of porous Scaffolds confirmed the formation of unidirectional microstructure, so that pore size measurement indicated the orientation of pores in the direction of solvent solidification. The addition of MNPs to the PLGA-gelatine Scaffolds had no particular effect on the morphology of the pores, but reduced slightly pore size distribution. The MNPs contained constructs demonstrated increased mechanical strength, but a reduced absorption capacity and biodegradation ratio. Stability of the MNPs and lack of iron release was the point of strength in this investigation and were determined by atomic absorption spectroscopy. The evolution of rat bone marrow mesenchymal stem cells performance on the hybrid structure under a static magnetic field indicated the potential of super-paramagnetic constructs for further pre-clinical and clinical studies in the field of neural regeneration.

Bioprinting in Vascularization Strategies

Three-dimensional (3D) printing technology has revolutionized tissue engineering field because of its excellent potential of accurately positioning cell-laden constructs. One of the main challenges in the formation of functional engineered tissues is the lack of an efficient and extensive network of microvessels to support cell viability. By printing vascular cells and appropriate biomaterials, the 3D printing could closely mimic in vivo conditions to generate blood vessels. In vascular tissue engineering, many various approaches of 3D printing have been developed, including selective laser sintering and extrusion methods, etc. The 3D printing is going to be the integral part of tissue engineering approaches; in comparison with other scaffolding techniques, 3D printing has two major merits: automation and high cell density. Undoubtedly, the application of 3D printing in vascular tissue engineering will be extended if its resolution, printing speed, and available materials can be improved.

Cytotoxic Effects of Coated Gold Nanoparticles on PC12 Cancer Cell.

BACKGROUND: The use of gold nanoparticles in medicine and especially in cancer treatment has been of interest to researchers. The effectiveness of this nanoparticle on cells significantly depends on the amount of its entry into the cells. This study was performed to compare the rate and mechanism of effect of gold nanoparticles coated with different amino acid on PC12 cancer cell line. MATERIALS AND METHODS: The PC12 cells line were exposed to various concentrations of amino acid coated and uncoated gold nanoparticles (0.5, 2.5 and 5 µM). Cell death rate was determined according to level of Lactate dehydrogenase (LDH) release from cells and MTT assay. In addition cell morphology and the amount of Cellular Reactive oxygen species (ROS) were studied. RESULTS: The uncoated gold nanoparticles have shown minor effects on cellular life. Gold nanoparticles coated by tryptophan at high concentrations (2.5, 5 and 25µM) increase in cancer cells metabolic activity. Gold nanoparticles coated by Aspartate also produce the largest amount of LDH and ROS in cancer cells and therefore caused of highest rate of apoptosis. CONCLUSION: The results showed that the nanoparticles coated with amino acids are affected on cellular metabolism and apoptosis more than uncoated nanoparticles. Also the smallest coated nanoparticles (coated by aspartate) have the most influence and by increasing the size, this effect was reduced.

A Review of the Clinical Implications of Breast Cancer Biology.

BACKGROUND: Histologically similar tumors may have different prognoses and responses to treatment. These differences are due to molecular differences. Hence, in this review, the biological interaction of breast cancer in several different areas is discussed. In addition, the performance and clinical application of the most widely-recognized biomarkers, metastasis, and recurrences from a biological perspective and current global advances in these areas are addressed. OBJECTIVE: This review provides the performance and clinical application of the most widely-recognized biomarkers, metastasis, and recurrences from the biological perspective and current global advances in these areas. METHODS: PubMed, Scopus, and Google Scholar were searched comprehensively with combinations of the following keywords: "breast cancer," "biological markers," and "clinical." The definition of breast cancer, diagnostic methods, biological markers, and available treatment approaches were extracted from the literature. RESULTS: Estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor-2 (HER-2), and Ki-67 are the most well-known biological markers that have important roles in prognosis and response to therapeutic methods. Some studies showed the response of ER-positive and PR-negative tumors to anti-estrogenic treatment to be lower than ER-positive and PR-positive tumors. Patients with high expression of HER-2 and Ki-67 had a poor prognosis. In addition, recent investigations indicated the roles of new biomarkers, such as VEGF, IGF, P53 and P21, which are associated with many factors, such as age, race, and histological features. CONCLUSION: The objective of scientists, from establishing a relationship between cancer biology infrastructures with clinical manifestations, is to find new ways of prevention and progression inhibition and then possible introduction of less dangerous and better treatments to resolve this dilemma of human society.