\u3cem\u3eIn vitro\u3c/em\u3e Effect of Graphene Structures as an Osteoinductive Factor in Bone Tissue Engineering: A Systematic Review

Graphene and its derivatives have been well‐known as influential factors in differentiating stem/progenitor cells toward the osteoblastic lineage. However, there have been many controversies in the literature regarding the parameters effect on bone regeneration, including graphene concentration, size, type, dimension, hydrophilicity, functionalization, and composition. This study attempts to produce a comprehensive review regarding the given parameters and their effects on stimulating cell behaviors such as proliferation, viability, attachment and osteogenic differentiation. In this study, a systematic search of MEDLINE database was conducted for in vitro studies on the use of graphene and its derivatives for bone tissue engineering from January 2000 to February 2018, organized according to the PRISMA statement. According to reviewed articles, different graphene derivative, including graphene, graphene oxide (GO) and reduced graphene oxide (RGO) with mass ratio ≤1.5 wt % for all and concentration up to 50 μg/mL for graphene and GO, and 60 μg/mL for RGO, are considered to be safe for most cell types. However, these concentrations highly depend on the types of cells. It was discovered that graphene with lateral size less than 5 µm, along with GO and RGO with lateral dimension less than 1 µm decrease cell viability. In addition, the three‐dimensional structure of graphene can promote cell‐cell interaction, migration and proliferation. When graphene and its derivatives are incorporated with metals, polymers, and minerals, they frequently show promoted mechanical properties and bioactivity. Last, graphene and its derivatives have been found to increase the surface roughness and porosity, which can highly enhance cell adhesion and differentiation

Synergistic Effect of Elicitors in Enhancement of Ganoderic Acid Production: Optimization and Gene Expression Studies

Ganoderma lucidum is one of the most well-known fungi, and has many applications in medicine. Ganoderic acid is among the valuable secondary metabolites of Ganoderma lucidum, and responsible for the inhibition of the tumor cell growth and cancer treatment. Application of ganoderic acid has been limited because of low yields of its production from Ganoderma lucidum. The present study aims to investigate the synergistic effect of elicitors including methyl jasmonate and aspirin on the production of ganoderic acid derived from Ganoderma lucidum mushroom in a shaken flasks using response surface methodology. The results showed that the optimal dose of methyl jasmonate and asprin significantly impacts on the amount of ganoderic acid production as a response (p<0.05). The proposed model predicted the maximum ganoderic acid production as 0.085 mgml-1 in which the optimal concentrations obtained for methyl jasmonate and asprin were 250 mM and 4.4 mM, respectively. Also the influence of ganoderic acid production on the expression of 3-hydroxy-3-methyl-glutaryl coenzyme A reductase and squalene synthase (two important metabolic pathway genes in ganoderic acid) was investigated, and the results showed that these genes’ expression has increased by 10 and 11 folds, respectively. 

Graphite/Gold Nanoparticles Electrode for Direct Protein Attachment: Characterization and Gas Sensing Application

In this work, graphite/gold nanoparticles (G/AuNPs) were synthesized through a facile chemical method, and its potential application for direct protein attachment for electrochemical detection of carbon monoxide (CO) was investigated. The preparation of G/AuNPs electrodes was optimized by synthesizing the nanoparticles in different concentration of HAuCl4.3H2O at various temperatures. The G/AuNPs electrode was subsequently modified by four types of mercaptopropionic acid, including 1-mercaptopropionic, 3-mercaptopropionic, 6-mercaptopropionic, and 11-mercaptopropionic acid, to achieve the best structure for protein attachment. Visible absorption and electrochemical studies showed that 3-mercaptopropionic acid possesses the best performance regarding the electrical conductivity between electrode and protein redox center. The cyclic voltammetry results revealed that the modified electrode has an appropriate performance for CO detection at very low concentrations while keeping a linear response. The limit of detection for the modified electrode was calculated to be about 0.2 ppb. Finally, the interactions of cytochrome C and carbon monoxides were simulated using molecular dynamics (MD), and the effect of protein conformation changes on the electrochemical signal was thoroughly examined. The simulation results suggested that the proposed electrochemical sensor has an acceptable performance for the detection of CO due to less fluctuation of amino acids near the protein chain in the presence of CO molecules

Natural Pigment Production by Monascus purpureus: Bioreactor Yield Improvement through Statistical Analysis

Among the ways of pigment production, microbial synthesis has gained more interest for high growth rate, easy extraction and high yield. Pigments are used in the food industry as natural colorants and preservatives; they also have pharmaceutical applications. In this study, fungus Monascus purpureus PTCC 5303 was used to produce red, orange and yellow pigments. At first, significant variables were screened based on Plackett-Burman’s design. The optimized value of two effective factors, i.e. concentration of yeast extract and K2HPO4 by three-level, was more studied by the response surface method (RSM). The most suitable level was 2.75 g/L for yeast extract and 1.5 g/L for K2HPO4. Antimicrobial activity of the pigments was shown on Gram-positive food-borne bacteria under optimal conditions. Moreover, pigment production at optimal conditions in a bioreactor was evaluated, and the rate of production of red, orange and yellow pigments was obtained to be 2.05, 1.55 and 0.78 (ODU/ml), respectively. 

A Glassy Carbon Electrode Modified with Reduced Graphene Oxide and Gold Nanoparticles for Electrochemical Aptasensing Of Lipopolysaccharides from Escherichia Coli Bacteria

An electrochemical aptasensor is described for the voltammetric determination of lipopolysaccharide (LPS) from Escherichia coli 055:B5. Aptamer chains were immobilized on the surface of a glassy carbon electrode (GCE) via reduced graphene oxide and gold nanoparticles (RGO/AuNPs). Fast Fourier transform infrared, X-ray diffraction and transmission electron microscopy were used to characterize the nanomaterials. Cyclic voltammetry, square wave voltammetry and electrochemical impedance spectroscopy were used to characterize the modified GCE. The results show that the modified electrode has a good selectivity for LPS over other biomolecules. The hexacyanoferrate redox system, typically operated at around 0.3 V (vs. Ag/AgCl) is used as an electrochemical probe. The detection limit is 30 fg·mL−1. To decrease the electrochemical potential for detection of LPS, Mg/ carbon quantum dots were used as redox active media. They decrease the detection potentialto 0 V and the detection of limit (LOD) to 1 fg·mL−1. The electrode was successfully used to analyze serum of patients and healthy persons

Optimization of Monacolin Production in a Controlled System

Monascus purpureus is a fungus that had been cultured on the rice in eastern Asian countries since thousands years ago and used as a food for long years. The fungus produces very valuable metabolites with polyketide structure. The most important metabolite is Monacolin K, lovastatin or competitive inhibitor of 3-Hydroxy-3-Methylglutaryl-Coenzyme A reductase (an affective enzyme in cholesterol synthesis). This metabolite has various properties including reducing blood cholesterol, preventing infection, and treatment of progressive renal disease, a variety of tumors, vascular diseases and bone fractures. In this study, Monascus purpureus PTCC5303 has been used for lovastatin production in liquid fermentation. The nutritional concentrations that were significant in biomass and lovastatin production including maltose and MgSO4 were optimized by Response Surface Methodology in a mili-bioreactor. The optimum concentration of maltose and MgSO4 was obtained as 10 g l-1 and 0.78 g l-1, respectively. According to our results, maximum lovastatin production under optimum conditions including maltose 10 g l-1, peptone 5 g l-1, MgSO4.7H2O 0.78 g l-1, MnSO4.H2O 0.5 gl-1, KH2PO4 4 g l-1, thiamine 0.1 g l-1, and pH=7 at 30 °C, 130 rpm and flow rate 1.8 l min-1 was obtained to be 309 μg l-1 after 10 days of fermentation period

Chitosan/Agarose/Graphene oxide nanohydrogel as drug delivery system of 5-fluorouacil in breast cancer therapy

Breast cancer refers to a very common deadly class of malignant tumors, especially in women worldwide. In the present study, a promising methodology has been developed to simultaneously improve the drug loading per-formance and achieve a sustained release of 5-fluorouracil (5-FU) as a model drug for breast cancer. For this purpose, a pH-sensitive and biocompatible hydrogel of chitosan/agarose/graphene oxide (CS/AG/GO) was first synthesized with glyoxal as cross-linker. 5-FU-loaded nanocomposites (NCs) of CS/AG/GO were then prepared via water-in-oil-in-water (W/O/W) emulsification technique. XRD and FTIR analyses confirmed the successful synthesis of the nanocarriers and gave insight on their crystalline structure and molecular interactions between the components. DLS demonstrated that the nanocarriers comprise nanoparticles with an average size of 197 nm and a PDI of 0.34. SEM revealed their spherical morphology and zeta potential measurements indicated an average surface charge of +23.5 mV. The drug loading and entrapment efficiencies (57% and 92%, respectively) were significantly higher than those reported previously for other nanocarriers. A very effective and sustained drug release profile was observed at pH 5.4; in 48 h, almost the entire 5-FU content was released. Moreover, effective cytotoxicity against breast cancer cell (BCC) lines (MCF-7) was observed: the cell viability upon in-cubation with CS/AG/GO/5-FU was about 23%, demonstrating its anti-cancer capability. Therefore, the syn-thesized NCs can potentially act as pH-sensitive nanovehicles for programmed release of 5-FU in breast cancer treatment.Comunidad de Madri

Electrochemical nanobiosensor based on reduced graphene oxide and gold nanoparticles for ultrasensitive detection of microRNA-128

Acute lymphoblastic leukemia (ALL) is one of the most prevalent cancers in children and microRNA-128 is amongst the most useful biomarkers not only for diagnosis of ALL, but also for discriminating ALL from acute myeloid leukemia (AML). In this study, a novel electrochemical nanobiosensor based on reduced graphene oxide (RGO) and gold nanoparticles (AuNPs) has been fabricated to detect miRNA-128. Cyclic Voltametery (CV), Square Wave Voltametery (SWV) and Electrochemical Impedance Spectroscopy (EIS) have been applied to characterize the nanobiosensor. Hexacyanoferrate as a label-free and methylene blue as a labeling material were used in the design of the nanobiosensors. It was found that the modified electrode has excellent selectivity and sensitivity to miR-128, with a limit of detection of 0.08761 fM in label-free and 0.00956 fM in labeling assay. Additionally, the examination of real serum samples of ALL and AML patients and control cases confirms that the designed nanobiosensor has the potential to detect and discriminate these two cancers and the control samples.Comunidad de Madri

Chitosan/Gamma-Alumina/Fe3O4@5-FU nanostructures as promising nanocarriers: physiochemical characterization and toxicity activity

Today, cancer treatment is an important issue in the medical world due to the challenges and side effects of ongoing treatment procedures. Current methods can be replaced with targeted nano-drug delivery systems to overcome such side effects. In the present work, an intelligent nano-system consisting of Chitosan (Ch)/Gamma alumina (gamma Al)/Fe3O4 and 5-Fluorouracil (5-FU) was synthesized and designed for the first time in order to influence the Michigan Cancer Foundation-7 (MCF-7) cell line in the treatment of breast cancer. Physico-chemical characterization of the nanocarriers was carried out using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), vibrating sample magnetometry (VSM), dynamic light scattering (DLS), and scanning electron microscopy (SEM). SEM analysis revealed smooth and homogeneous spherical nanoparticles. The high stability of the nanoparticles and their narrow size distribution was confirmed by DLS. The results of the loading study demonstrated that these nano-systems cause controlled, stable, and pH-sensitive release in cancerous environments with an inactive targeting mechanism. Finally, the results of MTT and flow cytometry tests indicated that this nano-system increased the rate of apoptosis induction on cancerous masses and could be an effective alternative to current treatments