A Survey of Gasoline Ameliorator, Methyl-Tert-Butyl Ether (MTBE) on Bovine Serum Albumin: A Spectroscopy and Molecular Dynamic Simulation Study.

Background: Methyl-Tert-Butyl Ether (MTBE) as a gasoline modifier is frequently added to fuels and used in plenty of worldwide applications. MTBE biodegradation in groundwater occurs slowly and produces water miscibility; therefore, it causes diverse environmental and human health concerns. Objectives: The interaction of MTBE with bovine serum albumin (BSA) as a model protein at physiological conditions is investigated to illustrate the possible interactions of MTBE with the body's proteins. Materials and Methods: Uv-visible, fluorescence, circular dichroism (CD) spectroscopy methods, and molecular modeling were used to analyze the MTBE's effect on BSA structure and dynamics. The constant protein concentration and various MTBE contents were used for possible interactions. Results: The protein structural analysis shows that MTBE binds to BSA via positive enthalpy and entropy via hydrophobic interactions. Molecular docking shows the participation of several amino acids in the MTBE-BSA interaction. The CD spectroscopy results show that the BSA structure was not changed in the MTBE concentrations utilized in the study. Molecular dynamics (MD) simulation results suggest that MTBE can slightly change protein structure in the last 50ns. Conclusion: Comparing experimental and MD simulation results demonstrated that the BSA secondary structure was maintained in the low concentration of the MTBE. The entropy and enthalpy parameters asserted the hydrophobic interaction was the major force in the interaction between the BSA and MTBE.

Mesenchymal stem cells encapsulation in chitosan and carboxymethyl chitosan hydrogels to enhance osteo-differentiation.

BACKGROUND: Recently biomaterials utilized for designing scaffolds in tissue engineering are not cost-effective and eco-friendly. As a result, we design and develop biocompatible and bioactive hydrogels for osteo-tissue regeneration based on the natural polysaccharide chitosan. Three distinct hydrogel components were used for this. METHODS: Hydrogels networks were created using chitosan 2% (CTS 2%), carboxymethyl chitosan 2% (CMC 2%), and 50:50 mixtures of CTS and CMC (CTS/CMC 50:50). Furthermore, scanning electron microscopy (SEM), Fourier transforms infrared spectroscopy (FTIR), degradation, and swelling behavior of design hydrogels were studied. Also, the cytocompatibility and osteo-differentiation potency were examined by encapsulating mesenchymal stem cells derived from adipose tissue (AMSCs) on the designed hydrogels. RESULTS: According to the findings, our results showed an acceptable pore structure, functional groups, and degradation rate of the designed hydrogels for in vitro evaluation. In addition, employing CMC instead of CTS or adding 50% CMC to the hydrogel component could improve the hydrogel's osteo-bioactivity without the use of external osteogenic differentiation agents. CONCLUSION: The CMC-containing hydrogel not only caused early osteogenesis but also accelerated differentiation to the maturity phase of osteoblasts.

Fe3O4 nanoparticles coated with carboxymethyl chitosan containing curcumin in combination with hyperthermia induced apoptosis in breast cancer cells.

Many studies have demonstrated that curcumin has potential anticancer properties. This research aims to study the effect of iron (II, III) oxide (Fe3O4) nanoparticles coated with carboxymethyl chitosan containing curcumin combination with hyperthermia on breast cancer cells. Magnetic nanoparticles coated with carboxymethyl chitosan containing curcumin (MNP-CMC-CUR) were prepared and specified. MCF-7, MDA-MB-231, and human fibroblast cells were treated with free curcumin and MNP-CMC-CUR at concentrations of 0-60 µM and at different time points. A combined therapy of MNP-CMC-CUR and hyperthermia was performed on MCF-7 cells. The cytotoxicity of curcumin and MNP-CMC-CUR combined with hyperthermia was assessed by MTT. The changes in TP53 and CASPASE3 gene expression were evaluated using real-time PCR. Both cell apoptosis and cell cycle were studied by Annexin/PI staining. The results of MTT showed that the IC50 amount of MNP-CMC-CUR has significantly decreased compared to free curcumin (p < 0.05) and MNP-CMC-CUR in combination with the hyperthermia, and significantly reducing the metabolic activity of the cells (p < 0.05). Real-time PCR results revealed the up-regulation of TP53 and CASPASE3 (p < 0.05). The combinational therapy-induced cell apoptosis (64.51%) and sub-G1 cell cycle were arrested in MCF-7 cells. Based on these observations, a combination of MNP-CMC-CUR with hyperthermia could inhibit the proliferation of MCF-7 cells.

The Drug Release Kinetics and Anticancer Activity of the GO/PVA-Curcumin Nanostructures: The Effects of the Preparation Method and the GO Amount.

The Graphene Oxide (GO) incorporated polyvinyl alcohol/sodium alginate (PVA-SA) composites with curcumin were prepared by the solvent casting and electro-spinning techniques. The GO was incorporated into PVA-SA nano-fiber and film matrixes, and the performance of these nano-composites as drug carriers was investigated. The effects of production method (film or mat) and GO amount on the water absorption properties and delivery of curcumin behaviors were investigated. The swelling and releasing were studied at the specific interval times in deionized water and phosphate buffer solution (pH = 7.4), respectively. The release kinetics was evaluated to find a suitable mechanism of the release. Finally, the anticancer activity of composite nano-fibers on the cancer cells was investigated. The XRD and FTIR analyses confirmed nanocomposites structures, and the successful incorporation was shown by scanning electron microscopy (SEM). The results showed that addition of the GO to PVA/SA decreased swelling ratio of the films (up to 31%) and increased the swelling ratio of the mats (up to 37.5%). However, for both film and mat, increasing of the GO amount reduced the curcumin release. Drug release decreasing up to 22.5% was observed for film, while a very high release decreasing up to about 70% was seen for mat. Also, both film and mat structures showed significant anti-cancer activity on MCF-7 cells. The lower cell viability was about 40 and 30% for film and mat, respectively. The kinetics evaluations suggested a Korsmeyer-Peppas model and Fickian controlled drug release.

Inhibitory effects of cold atmospheric plasma on the growth, virulence factors and HSP90 gene expression in Candida albicans.

In spite of the abundance of antifungal therapies, 75% of women in the world suffer from the second most common cause of vaginal infection named vulvovaginal candidiasis. This complication is characterized with overgrowth of Candida albicans. The low efficacy and side effects of current antifungal therapies have convinced the researchers to look for a non-antibiotic based treatment such as cold atmospheric plasmas (CAP). The aim of this research was to evaluate the effects of CAP on C. albicans growth, ergosterol and biofilm formation. In addition, antibiotic resistance, phospholipase and proteinase activity, and structural properties were examined with different exposure duration. Putative critical effect of CAP on the expression of HSP90 as a target of anti-fungal therapy was investigated. ROS production in C. albicans exposed to CAP was assessed. For this purpose, C. albicans subjected to 0, 90, 120, 150, 180 and 210 s of He/O2 (2%), and non-treated cells as control were examined in terms of the mentioned virulence factors. The results showed that CAP had a significant effect on inhibition of C. albicans growth, Inhibition of biofilm formation, ergosterol content, and fluconazole and amphotericin B antibiotic sensitivity were significant in 210 s treatment group. This effect was validated based on changes of the cell architecture and morphology given the microscopy imaging results. The expression of HSP90 in both C. albicans ATCC 10231 and C. albicans PFCC 9362 was inhibited in 210 s of exposition. CAP exposition induced intracellular ROS, which may cause membrane damage and cell death in C. albicans. Taken together, the potential of CAP for therapeutic purposes in C. albicans-induced fungal infections is supported.

Enhanced Adipose Mesenchymal Stem Cells Proliferation by Carboxymethyl-Chitosan Functionalized Polycaprolactone Nanofiber.

Background: Through combining two synthetic and natural polymers, scaffolds can be developed for tissue engineering and regenerative medicine purposes. Methods: In this work, carboxymethyl chitosan (CMC; 20%) was grafted to Polycaprolactone (PCL) nanofibers using the cold atmospheric plasma of helium. The PCL scaffolds were exposed to CAP, and functional groups were developed on the PCL surface. Results: The results of Fourier Transform Infrared Spectroscopy confirmed CMC (20%) graft on PCL scaffold. The Thiazolyl blue tetrazolium bromide assay showed a significant enhancement (p < 0.05) in the cell affinity and proliferation of adipose-derived stem cells (ADSCs) to CMC20%-graft-PCL scaffolds. After 14 days, bone differentiation was affirmed through alizarin red and calcium depositions. Conclusion: Based on the results, the CMC20%-graft-PCL can support the proliferation of ADSCs and induce the differentiation into bone with longer culture time.

Bone morphogenic protein-2 immobilization by cold atmospheric plasma to enhance the osteoinductivity of carboxymethyl chitosan-based nanofibers.

Electrospun polycaprolactone/carboxymethyl chitosan (PCL/CMC) nanofibers treated by helium cold atmospheric plasma (CAP) and grafted with bone morphogenic protein-2 (BMP-2) were used scaffolds for the osteodifferentiation of stem cells to. For in vitro study, human bone marrow-derived mesenchymal stem cells (hMSCs) were cultured on these scaffolds, and their behaviors were assessed via optical microscopy, MTT assay, and SEM. The osteogenic differentiation of the hMSCs was evaluated by calcium content and alkaline phosphatase assays, Alizarin red and immunofluorescence (ICC) staining, and RT-PCR. The results showed that scaffolds not only can support the proliferation of hMSCs but also can promote their differentiation to osteoblasts without using any external osteogenic differential agent. The RT-PCR and ICC data revealed that the CAP treatment and BMP-2-functionalization have synergic enhancement on the ossification of hMSCs. These fabricated scaffolds can be used as promising candidates for bone tissue engineering applications.

Increment in protease activity of Lysobacter enzymogenes strain by ultra violet radiation.

BACKGROUND AND OBJECTIVES: Increasing the amount of protease from microbial sources is in the focus of attention. Random mutagenesis by physical methods like ultraviolet (UV) radiation is a cost effective and convenient procedure for strain improvement. Therefore, in the present study attempts were made to investigate the effect of UV radiation on Lysobacter enzymogenes in order to increase its protease activity. MATERIALS AND METHODS: UV mutagenesis was induced in L. enzymogenes fresh culture at the distance of 20 cm from light source for different exposure times of 70, 90, 150 and 200 seconds. The mutated isolates were randomly cultured from the nutrient agar medium to casein agar plate, as a selective medium. The primary screening was performed by observing hydrolysis of casein in the plate and the secondary screening was carried out on skim milk agar on the basis of zone of hydrolysis using bacterial supernatants. Quantification of protease activity was done by Anson's method using tyrosine as standard. RESULTS: UV radiation resulted in obtaining 12 mutants out of 100 examined L. enzymogenes strains with increased protease activity. The mutant M2, at 90s exposure time was selected as the best mutant bacterium which produced 1.96 fold more protease over the parent strain. CONCLUSION: Random mutation by UV radiation is a simple and convenient method to increase the protease activity of Lysobacter enzymogenes. Furthermore, it seems that the middle time of exposure to UV, 90 s, was the best time because it can induce mutagenesis but did not hamper the bacteria growth and viability.

Chondroitin sulfate immobilized PCL nanofibers enhance chondrogenic differentiation of mesenchymal stem cells.

Cold Atmospheric Plasma (CAP) is used as a promising method in surface modification for immobilization of chondroitin sulfate functional biomacromolecules on PCL nanofibrous substrates for cartilage tissue engineering. The GAG-grafted scaffolds are able to successfully support the attachment and proliferation of mesenchymal stem cells (MSCs). The seeded scaffolds show the chondro-differentiation of MSCs during a 21-days cell culture in a non-differential medium. Expression of SOX9, Collagen10 and Collagen2 proved the chondro-inductive effect of GAG-grafted scaffolds. Besides, no external chondro-genic differential agent was used in the differentiation of MSCs to chondrocyte. The cells passed the last phase of chondrogenesis after 14 days of incubation. Thus, the GAG-fabricated fibrous scaffolds using CAP are potential candidates for cartilage tissue engineering.

Docetaxel-Chitosan nanoparticles for breast cancer treatment: cell viability and gene expression study.

Docetaxel acts through the inhibition of tubulin polymerization and reduction in the expression of BCL-2 gene. In this study, nanoparticles containing Docetaxel were prepared and their effects on the gene expression levels of BCL-2 and BAX genes were investigated. The drug was first conjugated to chitosan, and the nanoparticles were assembled in the presence of hyaluronic acid. Conjugations were confirmed by 1 H-NMR, and the obtained nanoparticles were characterized by dynamic light scattering and SEM. Cytotoxicity of the nanoparticles, cellular uptake, and cell death were evaluated. Finally, the effect of nanoparticles on the expression of BAX and BCL-2 genes in MCF-7 cells were investigated through real-time PCR. The results revealed that the prepared NPs had spherical shape with narrow size distribution of <200 nm with positive zeta potentials. In vitro cytotoxicity of Cs nanoparticles and free Docetaxel investigations revealed that increasing the treatment time with nanoparticles led to decrease in the rate of cell viability. BAX and BCL-2 gene expressions were decreased in nanoparticle-treated cells in comparison with intact cells, while the BAX/BCL-2 ratio was significantly elevated compared with free drug-treated cells after 72 h. Docetaxel-conjugated NPs may offer a promising treatment with low off-target toxicity for breast cancer.

Induction of growth arrest in colorectal cancer cells by cold plasma and gold nanoparticles.

INTRODUCTION: Guided treatments with nanoparticles and cold atmospheric plasma are a new approach in cancer therapy. Plasma is an ionized gas that has reactive and energetic particles and can be produced in the laboratory by different methods. MATERIAL AND METHODS: Plasma jet therapy was employed to irradiate HCT-116 cells (human colorectal cancer cells) which were cultured in the presence of gold nanoparticles (GNPs). Cell cytotoxicity was tested with 3-[4, 5-dimethylthiazol-2-yl]-2,5 diphenyltetrazolium bromide (MTT), and cancerous cell apoptosis was shown by 4',6-diamidino-2-phenylindole (DAPI) staining. RESULTS: The results showed that cell death was increased significantly with p < 0.001 by cold atmospheric plasma in the presence of gold nanoparticles. CONCLUSIONS: It appears that non-thermal plasma and gold nanoparticles synergism is a promising approach in colon cancer therapy.

Solvent effects on structural and thermochemical properties of p53 tumor-suppressor gene: a molecular modeling approach in drug design.

The p53 tumor-suppressor protein is a cellular phosphoprotein and a negative regulator of cell growth. Most p53 mutations occur in exons 5-8 within the DNA-binding domain. Therefore, p53 can potentially be targeted with novel drugs designed to bind to a mutation and restore its stability or wild-type conformation. For the current study, Hartree-Fock calculations were used to investigate the solvent-induced effects of five different solvent media (acetone, ethanol, methanol, dimethyl sulfoxide, and water) on the thermochemical parameters and relative energies, and on the multinuclear nuclear magnetic resonance shielding tensors of oxygen, nitrogen, and phosphorus nuclei, of GAT. To understand how the solvent affects the mutation region (the "hot spot") of p53, the relative energies of GAT in selected solvent media were determined. Some biological evidence suggested the structural stabilities of hot spots of GAT have the optimum temperature and solvent type for mutation. All the authors' findings are in accordance with common biological phenomena. Another important objective of this study was to compare the hydration Gibbs free energies of CUA and GAT in water using two different approaches where the solvent was treated as a continuum of the constant at different levels of Hartree-Fock theory. The Gibbs hydration energy values obtained in water with the polarized continuum model directly applied on the isolated CUA and GAT sequences were compared with those determined from the hydrated models with four, six, and eight water molecule clusters around the hot spots uracil and adenine. The clustered structures of water molecules around the hot spots of GAT (in DNA level) and CUA (in transcriptional level) were found to be energetically favored. The results of this study provide a reliable insight into the nature of mutation processes, which is of utmost importance for the study of biochemical structures, and provide a basis for drug design.