Facile one-pot synthesis of the mesoporous chitosan-coated cobalt ferrite nanozyme as an antibacterial and MRI contrast agent.

Cobalt ferrite (CoFe) nanoparticles (NPs) with appropriate physicochemical and biological properties have attracted great attention for biomedical applications. In the present study, chitosan-coated mesoporous CoFe (CoFeCH) NPs were synthesized using a facile one-step hydrothermal method and fully characterized using FE-SEM, EDS, BET, FTIR spectroscopy, DLS, TGA, XRD, and VSM. The spherical, highly colloidal, and monodispersed CoFeCH NPs with an average hydrodynamic size of 177.9 nm, PDI of 0.238 and zeta potential value of -33 represented a high saturation magnetization value of 59.37 emu g-1. N2 adsorption-desorption analysis confirmed the mesoporous structure of CoFeCH NPs with a type IV isotherm, calculated specific surface area of 89.583 m2 g-1 and total pore volume of 0.3668 cm3 g-1. CoFeCH NPs exhibited high antibacterial effects on S. aureus and E. coli, comparable with standard antibiotics, while CH-coating led to higher biocompatibility of CoFe NPs on human cells in vitro. CoFeCH NPs also showed significant peroxidase activity with a Km value of 14.37 and specific activity of 0.632 mmol min-1. CoFeCH NPs were successfully used as a MRI contrast agent with an R2 value of 91.3 mM-1 s-1. The overall results indicated the high potential of synthesized CoFeCH NPs by the present method for biomedical applications, especially as an antibacterial and MRI contrast agent.

Functionalization of anti-Brucella antibody based on SNP and MNP nanoparticles for visual and spectrophotometric detection of Brucella.

An Immuno-Nano-Biosensor with high sensitivity was designed based on iron and silica nanoparticles to detect B. abortus. Briefly explain, primary polyclonal antibody (IgG1) was conjugated on surface magnetic nanoparticles (MNPs) to form MNP-IgG1. Secondary polyclonal antibody (IgG2) and Horseradish Peroxidase enzyme were conjugated on silica nanoparticles (SNPs) to form HRP-SNP-IgG2. HRP-SNP-IgG2. MNP-IgG1 and HRP-SNP-IgG2 were added to B. abortus. The MNP-IgG1-B.abortus-IgG2-SNP-HRP complex was isolated from the reaction mixture using a magnet. After that, tetramethylbenzidine was added to the complex. The reaction was stopped with HCl and investigated using UV-Vis spectrophotometry. The nanoparticles' structure and size were investigated using SEM and DLS. Immuno-Nano-Biosensor sensitivity and specificity were determined. The SEM and DLS results indicated that the SNPs, MNPs, HRP-SNP-IgG2 and MNP-IgG1 size and structure were 35, 44, 60 and 56 nm, respectively. In addition, a good linear correlation was observed at 102-107 CFU mL-1 concentrations, which their linear equation and regression were Y = 0.3× + 0.18 and R2 0.982, respectively. The limitation of detecting B. abortus was 160 CFU mL-1. Finally, the results demonstrated that those designed Immuno-Nano-Biosensor could be specifically detected B. abortus and B. melitensis in real samples.

A fluorescence Nano-biosensors immobilization on Iron (MNPs) and gold (AuNPs) nanoparticles for detection of Shigella spp.

The highly sensitive and specificity detection are very important in diagnosis of foodborne pathogens and prevention of spread diseases. Therefore, in the present study, a highly sensitive fluorescence Nano-biosensors was designed for detection of Shigella species. For achieved this purpose, DNA probes and gold nanoparticles (AuNPs) were designed and synthesized, respectively. Then, two DNA probes as signal reporter were immobilized on surface of AuNPs. On the other hand, Iron nanoparticles (MNPs) were synthesized and modified with SMCC (Sulfosuccinimidyl 4-Nmaleimidomethyl cyclohexane-1- carboxylate). The 3th DNA probe was immobilized on surface of MNPs for separation of target DNA. The MNP-DNA probe and DNA probe-AuNP-fluorescence DNA probe were added to target DNA. The MNP- DNA probe-target DNA-DNA probe-AuNP-fluorescence DNA probe complex was isolated by a magnet. The fluorescence DNA probe was released on surface of AuNPs and the fluorescence intensity was read by fluorescence spectrophotometry. Sensitivity and specificity of designed Nano-biosensor was determined. The results showed that the fluorescence intensity was increased with increasing of target DNA concentration. Linear related between target DNA and fluorescence intensity was observed in 2.3 × 102 up to 2.3 × 107 CFU mL-1. The linear equation and regression were Y = 1.8 X + 23.4 and R2 0.9953. Limit of detection (LOD) were determined 90 CFUmL-1. The specificity of Nano-biosensor in present of other bacteria was confirmed.

Precise, direct, and rapid detection of Shigella Spa gene by a novel unmodified AuNPs-based optical genosensing system.

Early detection of infectious bacteria is a necessity for combating infectious diseases. Due to low infectious dose of Shigella, rapid and sensitive detection is needed. Compared to the presented genes, Spa gene can be introduced as a novel sequence for all species of Shigella detection. Herein, the possibility of Spa genes for detection of four species of Shigella was investigated for the first time by AuNPs-based optical genosensing system. In this method, AuNP-DNA probes were hybridized with Spa gene sequence. When the complementary target is present, it prevents the aggregation of the complex under acid environment and the solution remains red whereas in the absence of the specific sequence, it turns to purple. Therefore, visual detection is possible with bare eye. The comparison of this Optical DNA biosensor and PCR-based method showed that the proposed method is simple, cost-effective, rapid operation, with high or comparable detection limit of (LOD and LOQ: 8.14 and 26.6 ng mLl-1, respectively), without need of any expensive techniques, and equipments compared to the conventional methods. In conclusion, the described method may develop into a platform that could be utilized for detection of various bacterial species with high accuracy and prompt screening of samples.

Bio-barcode technology for detection of Staphylococcus aureus protein A based on gold and iron nanoparticles.

S. aureus is one of important causes of disease, food poisoning in humans and animals. The generally methods for detection of S. aureus is time consuming. Therefore, a new method is necessary for rapid, sensitive and specific diagnosis of S. aureus. In the present study, two probes and a Bio-barcode DNA were designed for detection of S. aureus (Protein A). Firstly, magnetic nanoparticle (MNPs) and gold nanoparticle (AuNPs) were synthesized at 80 °C and 100 °C, respectively. The AuNPs and the MNPs were functionalized with probe1, Bio-barcode DNA and probe2, respectively. Target DNA was added into the nanomaterial's system containing bio-barcode DNA-AuNPs-probe1 and probe2-MNPs to formed bio-barcode DNA-AuNPs-probe1-target DNA-probe2-MNPs complex. The bio-barcode DNA-AuNPs-probe1-target DNA-probe2-MNPs complex was separated with magnetic field. Finally, the bio-barcode DNA was released from surface of complex using DTT (0.8 M) and there was isolated of nanoparticles by magnetic field and centrifuge. The fluorescence intensity of bio-barcode DNA was measured in different concentrations of S. aureus (101 to 108 CFU mL-1) by fluorescence spectrophotometry. The results showed that standard curve was linearly from 102 to 107 CFU mL-1. Limit of detection of bio-barcode assay for both PBS and real samples was 86 CFU mL-1.

Identification of a new turncurtovirus in the leafhopper Circulifer haematoceps and the host plant species Sesamum indicum.

Turncurtoviruses (family: Geminiviridae; genus: Turncurtovirus) appear to have a high degree of genetic variation in Iran. Leafhoppers of the species Circulifer haematoceps (Mulsant and Rey, 1855) (family: Cicadellidae) were collected in 2014 from three geographical regions in south-eastern Iran (Orzoeyeh, Jiroft and Sirjan; Kerman province) and screened for the presence of turncurtoviruses using a combination of PCR and rolling circle amplification (RCA) methods. Eleven genomes of turncurtovirus were recovered and sequenced. Leafhoppers were sampled off sesame (S. indicum L.) and turnip (Brassica rapa sub sp. rapa). Thus, we identified three symptomatic sesame plants (yellowing, boat-shaped leaf curling, vein swelling on the lower leaf surfaces) from sesame farms in Jiroft. In these samples, we identified the same turncurtovirus as in the leafhoppers and have named it sesame curly top virus (SeCTV). Collectively, these SeCTV share > 98% genome-wide pairwise identity and ~ 87.3% to a recently identified turncurtovirus (sesame yellow mosaic virus; SeYMV) from sesame in Pakistan (GenBank accession MF344550). The SeCTV and SeYMV sequences share < 70% genome-wide pairwise identity with isolates of Turnip curly top virus and Turnip leaf roll virus, the two species in the genus Turncurtovirus. Based on the pairwise identities and phylogenetic analysis, SeCTV (n = 12) and SeYMV (n = 1) represent two strains of a new species in the genus Turncurtovirus.

The combinational effect of E6/E7 siRNA and anti-miR-182 on apoptosis induction in HPV16-positive cervical cells.

In the present research, we assumed that reducing the amounts of E6 and E7 oncoproteins by a specific siRNA sequence and recovering p53 and RB proteins, along with the recovery of the FOXO1 protein by applying anti-miR-182, would increase apoptosis and reduce proliferation rate in cancer cells. The HPV16-positive CaSki cervical cancer cell line was used. 48 hours after transfection of siRNA for targeting E6 and E7 oncoproteins and anti-miR-182, expression of its cellular targets p53, p21 and FOXO1 was assessed by real-time PCR, western blot analysis and immunocytofluorescence staining. In all treatments, apoptosis rate and viability were evaluated using Annexin-V-FITC apoptosis detection kits and MTT assays, respectively. Among the designed siRNAs, E6-1 and E7-2 proved the most effective in reducing E6 and E7 expressions by increasing the apoptotic rates to 12.4% and 16%, respectively, after 48 hours. Also, using anti-miR-182 increased apoptotic rate to 12.7% 48 hours after transfection of cervical cancer cells. The combinational use of either E6-1 or E7-2 siRNAs with anti-miR-182 resulted in a rise in apoptosis to 19.3% and 26%, respectively, higher than those obtained from the individual application of either without anti-miR-182. The simultaneous use of siRNA E6-1 and siRNA E7-2 with cisplatin increased sensitivity to cisplatin and reduced the viability of the cancer cells as compared to the use of cisplatin alone. The simultaneous use of cisplatin and anti-miR-182 had no considerable effect on viability or apoptosis rate compared to cisplatin alone.

Spectrophotometric, colorimetric and visually detection of Pseudomonas aeruginosa ETA gene based gold nanoparticles DNA probe and endonuclease enzyme.

Colorimetric DNA detection is preferred over other methods for clinical molecular diagnosis because it does not require expensive equipment. In the present study, the colorimetric method based on gold nanoparticles (GNPs) and endonuclease enzyme was used for the detection of P. aeruginosa ETA gene. Firstly, the primers and probe for P. aeruginosa exotoxin A (ETA) gene were designed and checked for specificity by the PCR method. Then, GNPs were synthesized using the citrate reduction method and conjugated with the prepared probe to develop the new nano-biosensor. Next, the extracted target DNA of the bacteria was added to GNP-probe complex to check its efficacy for P. aeruginosa ETA gene diagnosis. A decrease in absorbance was seen when GNP-probe-target DNA cleaved into the small fragments of BamHI endonuclease due to the weakened electrostatic interaction between GNPs and the shortened DNA. The right shift of the absorbance peak from 530 to 562nm occurred after adding the endonuclease. It was measured using a UV-VIS absorption spectroscopy that indicates the existence of the P. aeruginosa ETA gene. Sensitivity was determined in the presence of different concentrations of target DNA of P. aeruginosa. The results obtained from the optimized conditions showed that the absorbance value has linear correlation with concentration of target DNA (R: 0.9850) in the range of 10-50ngmL-1 with the limit detection of 9.899ngmL-1. Thus, the specificity of the new method for detection of P. aeruginosa was established in comparison with other bacteria. Additionally, the designed assay was quantitatively applied to detect the P. aeruginosa ETA gene from 103 to 108CFUmL-1 in real samples with a detection limit of 320CFUmL-1.

Recent biomedical applications of gold nanoparticles: A review.

Recent advances in nanotechnology are as a result of the development of engineered nanoparticles. Efficiently, metallic nanoparticles have been widely exploited for biomedical application and among them, gold nanoparticles (AuNPs) are highly remarkable. Consequent upon their significant nature, spherical and gold nanorods (Au NRs) nanoparticles attract extreme attention. Their intrinsic features such as optical, electronic, physicochemical and, surface plasmon resonance (SPR); which can be altered by changing the characterizations of particles such as shape, size, aspect ratio, or environment; ease of synthesis and functionalization properties have resulted to various applications in different fields of biomedicine such as sensing, targeted drug delivery, imaging, photothermal and photodynamic therapy as well as the modulation of two or three applications. This article reviewed the popular AuNPs synthesis methods and mentioned their established applications in various demands, especially in biological sensing.

Ultrahigh sensitive enhanced-electrochemiluminescence detection of cancer biomarkers using silica NPs/graphene oxide: A comparative study.

The increasing progress in using nano-biomaterials for medical purposes has opened new horizons toward researchers around the globe. To investigate the presence of these nanomaterials and the impacts they might have, a comparative enhanced-electrochemiluminescence immunosensing study has been designed. The effects of utilizing graphene oxide, silica, and gold nanoparticles in cancer diagnosis were evaluated during the quantification of two major cancer biomarkers (CEA and AFP) in different approaches. In other words, first and second approaches were designed to employ nanomaterials while third and fourth approaches were developed in absence of those. Accordingly, resulted LODs experienced dramatic amplification when nano-biomaterials were included in the immunosensor modification (for AFP: 1st and 3rd approaches: 1.36fg/ml in comparison with 0.39ng/ml, and for CEA: 2nd and 4th approaches: 1.90fg/ml versus 0.46ng/ml, respectively). Correspondingly, capability of nano-biomaterials for developing highly sensitive and more efficient immunosensors was validated through selectivity, stability, reproducibility, and feasibility examinations.

Sonocatalytic degradation of methylene blue by a novel graphene quantum dots anchored CdSe nanocatalyst.

Cadmium selenide/graphene quantum dots (CdSe/GQDs) nanocatalyst with small band gap energy and a large specific surface area was produced via a facile three-step sonochemical-hydrothermal process. The features of the as-prepared CdSe, GQDs and CdSe/GQDs samples were characterized by photoluminescence spectroscopy (PL), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), X-ray diffraction (XRD), Fourier transformed infrared (FT-IR), diffuse-reflectance spectrophotometer (DRS), and Brunauer-Emmett-Teller (BET) analysis. The sonocatalytic activity of the synthesized CdSe/GQDs was effectively accelerated compared with that of pure CdSe nanoparticles in degradation of methylene blue (MB). The influence of the CdSe/GQDs dosage (0.25-1.25g/L), initial MB concentration (20-30mg/L), initial solution pH (3-12), and ultrasonic output power (200-600W/L) were examined on the sonocatalytic treatment of MB aqueous solutions. The degradation efficiency (DE%) of 99% attained at 1g/L of CdSe/GQDs, 20mg/L of MB, pH of 9, and an output power of 200W/L at 90min of ultrasonic irradiation. Furthermore, DE% increased with addition of K2S2O8 and H2O2 as the enhancers via producing more free radicals. However, addition of sulfate, carbonate, and chloride as radical sweeper decreased DE%. Furthermore, well-reusability of the CdSe/GQDs sonocatalyst was demonstrated for 5 successive runs and some of the sonocatalytic generated intermediates were indicated by GC-MS analysis.

Neural differentiation of human induced pluripotent stem cells on polycaprolactone/gelatin bi-electrospun nanofibers.

In the present study, for the first time, polycaprolactone (PCL) and gelatin (GEL) were used for neural differentiation of human induced pluripotent stem cells (hiPSCs) in the form of bi-electrospun nanofibers. The electrospun fibers were evaluated by FTIR and tensile analysis. MTT assay was used to evaluate the toxicity on the scaffolds. The hiPSCs were seeded on the fibers and after 14days in neural differentiation medium. To confirm the differentiation, real-time PCR and immunocytochemistry (ICC) analyses were performed. For morphological studies of fibers and cultured cells on them, scanning electron microscopy (SEM) and optical microscopy (OM) were used. Our results indicated that hiPSCs had differentiated to neural cells completely after incubation time. Our study demonstrates that PCL/GEL bi-electrospun nanofibers not only have the capability to support hiPSCs differentiation to neural cells, but they also are able to enhance and improve such process. Overall, PCL/GEL scaffolds seem to be a feasible, reliable and easily accessed composite for further tissue engineering experiments.

Identification of a Nanovirus-Alphasatellite Complex in Sophora alopecuroides.

Viruses in the genus Nanovirus of the family Nanoviridae generally have eight individually encapsidated circular genome components and have been predominantly found infecting Fabaceae plants in Europe, Australia, Africa and Asia. For over a decade Sophora alopecuroides L. (Fabaceae) plants have been observed across Iran displaying dwarfing, yellowing, stunted leaves and yellow vein banding. Using a high-throughput sequencing approach, sequences were identified within one such plant that had similarities to nanovirus genome components. From this plant, the nanovirus-like molecules DNA-R (n=4), DNA-C (n=2), DNA-S (n=1), DNA-M (n=1), DNA-N (n=1), DNA-U1 (n=1), DNA-U2 (n=1) and DNA-U4 (n=1) were amplified, cloned and sequenced. Other than for the DNA-R, these components share less than 71% identity with those of other known nanoviruses. The four DNA-R molecules were highly diverse, sharing only 65-71% identity with each other and 64-86% identity with those of other nanoviruses. In the S. alopecuroides plant 14 molecules sharing 57.7-84.6% identity with previously determined sequences of nanovirus-associated alphasatellites were also identified. Given the research activity in the nanovirus field during the last five years coupled with high-throughput sequence technologies, many more diverse nanoviruses and nanovirus-associated satellites are likely to be identified.

Genome Sequences of Beet curly top Iran virus, Oat dwarf virus, Turnip curly top virus, and Wheat dwarf virus Identified in Leafhoppers.

Implementation of a vector-enabled metagenomics approach resulted in the identification of various geminiviruses. We identified the genome sequences of Beet curly top Iran virus, Turnip curly top viruses, Oat dwarf viruses, the first from Iran, and Wheat dwarf virus from leafhoppers feeding on beet, parsley, pumpkin, and turnip plants.

Affinity enhancement of nanobody binding to EGFR: in silico site-directed mutagenesis and molecular dynamics simulation approaches.

Epidermal growth factor receptor (EGFR), a transmembrane glycoprotein, is overexpressed in many cancers such as head-neck, breast, prostate, and skin cancers for this reason it is a good target in cancer therapy and diagnosis. In nanobody-based cancer diagnosis and treatment, nanobodies with high affinity toward receptor (e.g. EGFR) results in effective treatment or diagnosis of cancer. In this regard, the main aim of this study is to develop a method based on molecular dynamic (MD) simulations for designing of 7D12 based nanobody with high affinity compared with wild-type nanobody. By surveying electrostatic and desolvation interactions between different residues of 7D12 and EGFR, the critical residues of 7D12 that play the main role in the binding of 7D12 to EGFR were elucidated and based on these residues, five logical variants were designed. Following the 50 ns MD simulations, pull and umbrella sampling simulation were performed for 7D12 and all its variants in complex with EGFR. Binding free energy of 7D12 (and all its variants) with EGFR was obtained by weighted histogram analysis method. According to binding free energy results, GLY101 to GLU mutation showed the highest binding affinity but this variant is unstable after 50 ns MD simulations. ALA100 to GLU mutation shows suitable binding enhancement with acceptable structural stability. Suitable position and orientation of GLU in residue 100 of 7D12 against related amino acids of EGFR formed some extra hydrogen and electrostatic interactions which resulted in binding enhancement.

An enquiry on appropriate selection of polymers for preparation of polymeric nanosorbents and nanofiltration/ultrafiltration membranes for hormone micropollutants removal from water effluents.

To analyze polymeric nanosorbents and nanofiltration/ultrafiltration membranes for hormone micropollutants removal from water effluents, here an in-through investigation on the suitability and compatibility of various polymers has been carried out. For this work, estradiol, estrone, testosterone, progesterone, estriol, mestranol, and ethinylestradiol were considered. A total number of 452 polymers were analyzed and initially screened using Hansen solubility parameters. The identified good pairs of hormones and polymers then were examined to obtain the equilibrium capacity of hormones removal from water effluents using a modified Flory-Huggins model. A distribution coefficient was defined as the ratio of hormones in water effluent phase and polymer phase. For removal of mestranol, estradiol and ethinylestradiol, no compatible polymer was identified based on initial screening of collected database. Three compatible polymers were identified for estriol. For progesterone, a wide variety of polymers was identified as good matching of polar, dispersion and hydrogen forces contributions can be observed for these pairs. For estrone, only two polymers can be proposed due to the mismatch observed between polar, dispersion and hydrogen forces contributions of other polymers and this hormone. The phase calculations showed that not all the identified good pairs could be used for practical separation applications. The domain of applicability of each good pair was investigated and potential polymers for practical micropollutants removal together with their removal capacity were represented in terms of phase envelops. The theoretical approach follows fundamental chemical thermodynamic equations and then can be simply applied for any system of interest.

Splicing features in the expression of the complementary-sense genes of Beet curly top Iran virus.

Beet curly top Iran virus (BCTIV) is a distinct geminivirus which has been reported from sugar-beet-growing farms in Iran. In this study, the role of the splicing in expression of complementary-sense genes of BCTIV was studied. Total RNA was extracted from BCTIV-infected tissue, and the predicted intron position of complementary-sense mRNA transcripts was amplified by RT-PCR followed by cloning of the amplicons. Sequence confirmed that both spliced and unspliced mRNAs are synthesized by the same transcription unit. Sequence comparison showed that a 155-nt segment (intron) corresponding to nucleotides 1890-2044 of the viral genome has been removed from the latter transcript and therefore fusion of the C1:C2 genes resulted creation of a continuous reading frame for potential production of intact replication initiator protein (Rep). BCTIV intron comprises of most consensus splicing signals required for splicing in eukaryotes and several plant viruses including mastre- and capulaviruses.

Fluorescence bio-barcode DNA assay based on gold and magnetic nanoparticles for detection of Exotoxin A gene sequence.

Bio-barcode DNA based on gold nanoparticle (bDNA-GNPs) as a new generation of biosensor based detection tools, holds promise for biological science studies. They are of enormous importance in the emergence of rapid and sensitive procedures for detecting toxins of microorganisms. Exotoxin A (ETA) is the most toxic virulence factor of Pseudomonas aeruginosa. ETA has ADP-ribosylation activity and decisively affects the protein synthesis of the host cells. In the present study, we developed a fluorescence bio-barcode technology to trace P. aeruginosa ETA. The GNPs were coated with the first target-specific DNA probe 1 (1pDNA) and bio-barcode DNA, which acted as a signal reporter. The magnetic nanoparticles (MNPs) were coated with the second target-specific DNA probe 2 (2pDNA) that was able to recognize the other end of the target DNA. After binding the nanoparticles with the target DNA, the following sandwich structure was formed: MNP 2pDNA/tDNA/1pDNA-GNP-bDNA. After isolating the sandwiches by a magnetic field, the DNAs of the probes which have been hybridized to their complementary DNA, GNPs and MNPs, via the hydrogen, electrostatic and covalently bonds, were released from the sandwiches after dissolving in dithiothreitol solution (DTT 0.8M). This bio-barcode DNA with known DNA sequence was then detected by fluorescence spectrophotometry. The findings showed that the new method has the advantages of fast, high sensitivity (the detection limit was 1.2ng/ml), good selectivity, and wide linear range of 5-200ng/ml. The regression analysis also showed that there was a good linear relationship (∆F=0.57 [target DNA]+21.31, R2=0.9984) between the fluorescent intensity and the target DNA concentration in the samples.

Comparison of antibody immobilization strategies in detection of Vibrio cholerae by surface plasmon resonance.

Surface plasmon resonance immunosensor for the detection of bacterial cells was first reported in 1998 with high detection limit as much as 107 cfu/ml. Since then, many efforts have been made aiming to lower the detection limit and improve the sensitivity of detection. The aim of this study was to compare the effect of four most frequently used immobilization strategies, including direct physical adsorption (physisorption), covalent immobilization via self-assembled monolayer (SAM) formation, bioaffinity immobilization using protein G-mediated immobilization and using mixed SAM of alkane thiols on signal strength of detection of Vibrio cholerae using these modified surfaces. The most widely used strategy, covalent binding of antibodies to sensor chip via SAM formation, gave the highest immobilization density and mixed SAM of 20/80 (v/v) of 11-mercaptoundecanoic acid (11-MUA)/9-mercapto-1-nonanol resulted in the least surface coverage in antibody immobilization step. To optimize surface density in covalent immobilization, four different concentrations (12.5, 25, 50, and 100 µg/ml) of anti-OmpW were immobilized on 11-MUA modified gold chips and maximum interaction response was achieved at 25 µg/ml. The interaction response signals for detection of V. cholerae using immobilized anti-OmpW were in this order: Oriented immobilization using protein G/antibody complex > mixed SAM of 11-MUA and 9-mercapto-1-nonanol > homogenous 11-MUA SAM > direct physical adsorption. In order to evaluate interaction studies in real sample condition, waste water samples that were artificially spiked with V. cholerae were tested and the authors concluded that for real samples, it is better to setup experiment with low surface coverage such as mixed SAM to overcome nonspecific adsorption.

Osteoblast differentiation of mesenchymal stem cells on modified PES-PEG electrospun fibrous composites loaded with Zn2SiO4 bioceramic nanoparticles.

Tissue engineering has attracted a great deal of interest by combining fibrous scaffolds and stem cells regarding bone regeneration applications. In the present study, polymeric fibrous polyethersulphone-polyethylene glycol (PES-PEG) was fabricated by electrospinning. It was then treated with NH3 plasma to enhance surface hydrophilicity, cell attachment, growth and differentiation potential. X-ray photoelectron spectroscopy (XPS) measurements were used to evaluate the modification of the scaffold's surface chemistry. Electrospun scaffolds were coated with willemite (Zn2SiO4) bioceramic nanoparticles. Scaffold characterization was done by scanning electron microscope (SEM), differential scanning calorimetry (DSC), contact angle measurements and tensile analysis. MTT assay was used to assess the biocompatibility of fibrous scaffolds loaded with Zn2SiO4 regarding proliferation support. Osteogenic differentiation of cultured human mesenchymal stem cells (hMSCs) on fibers was evaluated using common osteogenic markers such as alkaline phosphatase (ALP) activity, calcium mineral deposition, quantitative real-time PCR (qPCR) and immunocytochemical analysis (ICC). According to the results, proliferation and osteogenic differentiation of hMSCs were significantly enhanced after coating Zn2SiO4 on fibrous scaffolds. These results were detected by higher ALP activity, biomineralization and expression of osteogenic related genes and proteins in differentiated hMSCs. In conclusion, our results indicated that the combination of Zn2SiO4 nanoparticles and electrospun fibers is able to provide a new, suitable and more efficient matrix to support stem cells differentiation for bone tissue engineering applications.