Sonochemical synthesis of ErVO4/MnWO4 heterostructures: Application as a novel nanostructured surface for electrochemical determination of tyrosine in biological samples

Present strategy introduces a novel method established for the synthesis of spherical shape ErVO4/MnWO4 heterostructures by a sonochemical method. This heterostructures with optima morphology can be synthesized by changing power and time ultrasound irradiation without any capping agent. BET analysis revealed that ErVO4/MnWO4 prepared in the presence of ultrasonic procedure has 75 times specific surface area as much as that of those was produced in the absence of ultrasonic rays. A variety of analyses (i.e., BET, XRD, TEM, EDS, FT-IR, and SEM) were applied for characterization of the ErVO4/MnWO4. Next, a selective and sensitive nanostructured sensor based on ErVO4/MnWO4 nanocomposite modified carbon paste electrode (ErVO4/MnWO4/CPE) was constructed for electrochemical detection of tyrosine (Tyr). The electrochemical characterizations were performed using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV). Compared with the unmodified CPE, the oxidation peak current was significantly enhanced for Tyr. The impact of effective parameters on voltammetric response of Tyr was analyzed with design of experiments (DOE) and response surface methodology (RSM). Under the optimized conditions, the oxidation peak current of Tyr was linear over a range of 0.08�400.0 μM with a detection limit of 7.7 nM. Finally, the usage of the proposed method was confirmed by the recovery tests of Tyr in biological samples. © 201

Design and synthesis of mucoadhesive nanogel containing farnesol: investigation of the effect on HWP1, SAP6 and Rim101 genes expression of Candida albicans in vitro

The evolution of drug resistance of Candida species to conventional antifungal agents has been a major medical challenge worldwide; attempt to use the potential antifungal agents with appropriate therapy efficacy and minimum effects is considerably growing. This study was conducted to evaluate the use of nanogel as a nanocarrier for pharmaceutical application of farnesol. The nanogels were synthetized using alginate (AL) and chitosan (CS) polymers containing 300 µM of farnesol in the nano-range 42-70�nm size. In vitro release studies indicated that release of farnesol from CS and AL nanogels was as 58 and 37, respectively. Chitosan nanogel showed more in inhibitory zone as compared to AL nanogel (9�mm). Also, cytotoxicity assay showed no significant difference between control and treatment groups (p>.05). Finally, the effect of nanogels on genes expression of HWP1, SAP6 and Rim101 in Candida albicans ATCC10231 was assessed using real-time polymerase chain reaction (PCR). Expression of HWP1 and SAP6 genes in C. albicans treated with CS nanogel was significantly decreased (p<.01). In general, the obtained finding showed that, CS nanogel contains farnesol with proper antifungal activity and as a new approach used in pharmaceutical applications against C. albicans; however, more studies in vitro and in vivo are needed in the future

Immobilization of Thermoalkalophilic Lipase from Bacillus atrophaeus FSHM2 on Amine-Modified Graphene Oxide Nanostructures: Statistical Optimization and Its Application for Pentyl Valerate Synthesis

Synthesis of (3-aminopropyl) triethoxysilane (APTES)-functionalized graphene oxide (GO) nanosheets, statistical optimization of conditions for immobilization of Bacillus atrophaeus lipase (BaL) on as-synthesized support, and application of the immobilized BaL for esterification of valeric acid were carried out in this investigation. The optimum specific activity of the immobilized BaL (81.60 ± 0.28 U mg�1) was achieved at 3 mg mL�1 of GO-NH2, 50 mM of phosphate buffer, pH 7.0, 60 min sonication time, 100 mM glutaraldehyde, 25 U mL�1 of enzyme, and 8 h immobilization time at 4 °C. The immobilized BaL retained about 90 of its initial activity after 10 days of storage. Moreover, about 70 of the initial activity of the immobilized BaL was retained after 10 cycles of application. The results of esterification studies exhibited that maximum pentyl valerate synthesis using the free BaL (34.5) and the immobilized BaL (92.7) occurred in the organic solvent medium (xylene) after 48 h of incubation at 60 °C. © 2019, Springer Science+Business Media, LLC, part of Springer Nature

Surface modification and bioconjugation of anti-CD4 monoclonal antibody to magnetic nanoparticles as a highly efficient affinity adsorbent for positive selection of peripheral blood T CD4+ lymphocytes

Magnetic activated cell sorting (MACS) is a straightforward and time-saving procedure for isolation of different healthy functional cells. The present study aimed for the developing of a new MACS-based platform for isolation of peripheral blood T CD4+ lymphocytes. For this goal, first: Fe3O4 magnetic nanoparticles (MNP) were prepared by co-precipitation of Fe (III) and Fe (II) ions and then coated by SiO2 shell, followed by the grafting of N-(phosphonomethyl) iminodiacetic acid (PMIDA) on the surface of fabricated MNP, Fe3O4@SiO2@PMIDA were formed. These MNP were further tested for their ability to bind CD4 T lymphocytes. Through conjugation of the anti-CD4 monoclonal antibody on the surface of Fe3O4@SiO2@PMIDA MNP. The newly developed immunomagnetic particles efficiently isolated T CD4+ lymphocytes from whole blood with high purity Therefore, our MNP afford an efficient tool for the cell separation process and further present the dramatic potential to be applied to other areas of biomedical application. © 202

Optimization of immobilization conditions of Bacillus atrophaeus FSHM2 lipase on maleic copolymer coated amine-modified graphene oxide nanosheets and its application for valeric acid esterification

The thermoalkalophilic lipase from Bacillus atrophaeus (BaL) was immobilized onto amine-functionalized graphene oxide nanosheets coated with the poly (maleic anhydride-alt-1-octadecene) copolymer (GO-NH2-PMAO) and activated with glutaraldehyde as spacer arm through interfacial activation and subsequent multipoint covalent attachment. Experimental design method was applied for optimization of immobilization conditions including GO-NH2-PMAO concentration, buffer concentration, pH, sonication time, enzyme concentration, glutaraldehyde concentration, time, and temperature. The optimum specific activity of the immobilized BaL (105.95 ± 2.37 U/mg) reached at 5 mg/mL for GO-NH2-PMAO, 25 mM of buffer, pH 6.0, 60 min sonication time, 100 mM glutaraldehyde, 60 U/mL of enzyme, and 4 h of immobilization time at 25 °C, which was very close to the predicted amount (106.08 ± 1.42 U/mg). Maximum immobilization yield (81.35) and efficiency (277.63) were determined in optimal immobilization conditions. The obtained results clearly indicated that the immobilized BaL exhibited better stability at extreme temperature and pH than the free BaL. At temperature of 90 °C and pH 11, more than 90 of the initial activity of the immobilized BaL was retained. Furthermore, the immobilized BaL retained about 90 of its initial activity after 10 days of storage and 6 cycles of application. The esterification studies showed that maximum bioconversion of valeric acid to pentyl valerate using the free BaL (34.5) and the immobilized BaL (96.3) occurred in the xylene medium after 48 h of incubation at 60 °C. Therefore, the BaL immobilized on GO-NH2-PMAO was introduced as an effective biocatalyst to synthesize green apple flavour ester. © 202

Synthesis, characterization and antifungal activity of a novel formulated nanocomposite containing Indolicidin and Graphene oxide against disseminated candidiasis

Objective: Candidiasis is one of the most opportunistic fungal infections in immunocompromised patients. The emergence of multidrug-resistant Candida species necessitates the development of novel antifungal agents. Seeking to the discovery of natural antifungal agents, this study aimed to synthesize a novel formulated nanocomposite containing Indolicidin (IN), antimicrobial peptide, and Graphene oxide (GO), kind of nanomaterial, against Candida growth using in vitro and in vivo experiments for the first time. Methods: The formulated nanocomposite (GO-IN) synthetized and was characterized using scanning electron microscopy, X-ray power diffraction, and fourier transform infrared method analysis. The in vitro antifungal activity of fluconazole (FLU), GO, IN, and GO-IN was determined against Candida albicans (C. albicans) compared to control groups, cell cytotoxicity assay on human intestinal epithelial cells (IEP) and hemolytic activities were performed. Moreover, in vivo experiments of nanocomposite were assessed in BALB/c mice. Results: Our results showed that nanocomposite had the highest inhibitory effect against C. albicans (MIC 3.12 μg/mL) compared with flu (MIC 4 μg/mL), IN (MIC 12.5 μg/mL), and GO (MIC 6.25 μg/mL). Viability of human intestinal cell line at the MIC concentration (3.12 μg/mL) of nanocomposite (GO-IN) was detected as 60 (P < 0.05). The results of hemolytic activity showed that nanocomposite cause 2.73 of red blood cell membrane damage. For in vivo experiments, infected mice were successfully treated with GO-IN once a day within 7 days. GO-IN treated group eliminated the Candida infection in the spleen and liver of BALB/c mice (P = 0.001) similar to fluconazole. There was no significant difference in histological manifestations between flu and GO-IN groups. Conclusion: This study suggests that synergistic combination of GO and IN provide a new option, representing a potential therapeutic efficiency against disseminated candidiasis in an animal model as well as might be used as adjunct therapy in the management of candidiasis. However, further investigation is needed to evaluate the efficacy of the nanocomposite. © 2018 Elsevier Masson SA

Embedding of L�Arginine into graphene oxide (GO) for endotoxin removal from water: Modeling and optimization approach

Endotoxin, also called lipopolysaccharides (LPS), has strong biological effects, even at a very low concentration in humans. In this study, surface functionalization of graphene oxide (GO) with L�Arginine amino acid was successfully prepared using epichlorohydrin as a coupling agent (GO�EPI�L�Arg) for endotoxin removal from water. Characterization of Novel GO�EPI�L�Arg was confirmed by an analytical technique. The model was optimized using response surface methodology (RSM) via various input parameters. The effect of concomitant anions was also investigated to establish and simulate competitive endotoxin adsorption in real hemodialysis water supply. The pH and endotoxin concentration had an antagonistic effect on the quadratic model. The endotoxin adsorption process was better fitted by pseudo-second-order model with Qmax value of 139.47 EU/mg, while the equilibrium followed the Langmuir isotherm with the maximum monolayer adsorption capacity of 154.85 EU/mg. The coefficient of determination (R2=0.9761), non�significant lack of fit (p &gt; 0.05), and p�value with low probability (&lt;5.596 � 10�11) revealed a regression model with a good fit with input variables. The GO�EPI�L�Arg nanocomposite could be regenerated more than four times based on their adsorption-desorption cycles, with a slight loss in adsorption capacity. The results suggested that the GO�EPI�L�Arg can be applied as an effective adsorbent for endotoxin removal from water. © 2020 Elsevier B.V