NPs Nanocomposites Research Articles

Design and green synthesis of carbon Dots/Gold nanoparticles Composites and their applications for neurotransmitters sensing based on emission Spectroscopy

Changes in the neurotransmitters are indications for several diseases. Several sensors were reported for monitoring dopamine (DA), but the simple and accurate DA detection in biological samples still faces many challenges. The research proposal aims to develop an optical sensor for detecting neurotransmitters based on luminescence emission spectra in different biological samples. Carbon dots (CDs) were fabricated based on a green synthesis route. Then the prepared CDs were decorated with varying concentrations of gold nanoparticles (Au NPs). The synthesis process was optimized, and the obtained CDs/Au NPs nanocomposites were applied as neurotransmitters’ optical nanosensors. The optical nanosensor approach provides easy and sensitive multiplex analysis. A wide range of neurotransmitters was monitored. The developed sensor’s sensitivity, selectivity, and reproducibility were investigated. Au NPs act as CDs’ stabilizers, enhancing the emission effect, and scaffolds for binding DA with CDs’ surface. DA moieties bind to CDs through the interaction between the DA-NH2 groups and Au NPS. Due to electron transfer, the bonding of DA molecules leads to fluorescence quenching of AuNPs/CDs. The Au-CDs-based DA fluorescence showed high sensitivity with adetection limit, and limit quantification of 2.04 nM and 6.18 nM, respectively. Furthermore, the selectivity of the sensor was investigated in the presence of glucose, uric acid (UA), and ascorbic acid (AA), which showed no interference effect at 10 times higher concentrations. Moreover, the proposed sensor has been successfully utilized for DA detection in human serum samples with a high recovery efficiency between 98.83 % and 103.5 %.

Synergistic effects in PPS/PVA/Fe3O4/Ag NPs nanocomposites for enhanced photocatalytic degradation of methylene blue

Synergistic effects in PPS/PVA/Fe3O4/Ag NPs nanocomposites for enhanced photocatalytic degradation of methylene blue

Conceptual rationale for the use of chemically modified nanocomposites for active influence on atherosclerosis using the greater omentum model of experimental animals

The use of chemically modified nanocomposites for atherosclerotic plaques can open up new opportunities for studying their effect on changing the structure of the plaque itself. It was shown on the model of the greater omentum of two groups of experimental animals (rats n = 30), which were implanted with Fe@C NPs nanocomposites of 10–30 Nm size into the omentum area. Group 1 (n = 15) consisted of animals that were implanted with chemically modified Fe@C NPs nanocomposites and control group 2 (n = 15) was with non-modified Fe@C NPs nanocomposites. After 1, 2 and 3 weeks we conducted the morphological study of changes in the structure of the omentum using two dyes (Nile Blue and Sudan III), which are specific for adipose tissue. Chemically modified nanocomposites have demonstrated, in contrast to non-modified nanoparticles, to cause morphological changes in the structure of the greater omentum accompanied by the probable release of a similar antiatherogenic factor.

A Novel MXene@MOF@Pt NPs-Based Enzyme-Free Electrochemical Sensor for Highly Sensitive Detection of Hydrogen Peroxide Released from Living Cells

Rapid and accurate detection of hydrogen peroxide (H2O2), an important reactive oxygen species (ROS) released from living cells, is of great significance for early diagnosis of tumors. Here, a high sensitive enzyme-free electrochemical sensor for the detection of H2O2 released from living cells was constructed based on MXene@ZIF-8@Pt NPs nanocomposites. Through the characterization of physical and chemical properties, it was observed that Pt NPs with excellent catalytic activity were uniformly supported on MXene@ZIF-8, which exhibited excellent conductivity and large specific surface area. Thanks to the significantly enhanced catalytic activity derived from the successful integration of MXene, ZIF-8 and Pt NPs, under the optimal conditions, the sensing platform based on MXene@ZIF-8@Pt NPs exhibited a wide linear range from 355.4 nM to 21.75 mM, with a limit of detection as low as 120.9 nM, while showing satisfactory reproducibility and selectivity. Furthermore, the developed electrochemical sensor enables real-time monitoring of H2O2 released from living Hela cells under N-formylmethionyl-leucyl-phenylalanine stimulation. Overall, the MXene@ZIF-8@Pt NPs developed in this article will become a promising candidate in monitoring physiological processes.

CTAB-Co-MOFs@AuPt NPs as signal probes for the electrochemical detection of carcinoembryonic antigen 15-3.

A sensitive electrochemical strategy for carcinoembryonic antigen 15-3 (CA15-3) detection isreported using CTAB-Co-MOFs@AuPt NPs as signal probes. The electrochemical strategy was designed as follows: First, the graphene aerogel@gold nanoparticles (GA@Au NPs) nanocomposites were employed to modify the sensing surface for promoting electron transfer rate and primary antibody (Ab1) immobilization due to GA possesses a large specific surface area, eminent conductivity, and a 3D network structure. Cobalt metal-organic frameworks (CTAB-Co-MOFs) synthesized were then used as a carrier for AuPt NPs and secondary antibody (Ab2) immobilization (notes: labelled-Ab2). With sandwich immunoreaction, the labelled-Ab2 was captured on the surface of the GA@Au NPs nanocomposites. Finally, differential pulse voltammetry (DPV) was employed to register the electrochemical signal of the immunosensor at the potential of - 0.85V (vs SCE) in phosphate buffer saline (PBS) containing 2.5mM H2O2. It was verified that the electrochemical reduction signal from Co3+ to Co2+ was recorded. The AuPt NPs could catalyze the reaction of H2O2 oxidizing Co2+ to Co3+, resulting in the amplification of the electrochemical signal. Under the selected conditions, the immunosensor can detect CA15-3 in the range10 µU/mL to 250 U/mL with a low detection limit of 1.1 µU/mL. In the designed strategy, the CTAB-Co-MOFs were not only employed as carriers for AuPt NPs, but also acted as signal probes. The CTAB-Co-MOFs were investigated including SEM, TEM, XPS, and XRD. The applicationability of theimmunosensor was evaluated using serum sample, demonstrating the immunosensor can be applied to clinic serum analysis.

Three‐dimensional porous magnetic polyaniline supported Ag nanoparticles nanocomposites as an efficient and recyclable catalyst for nitrophenol reduction

AbstractAg nanoparticles (Ag NPs) nanocomposites are promising catalysts for nitro compound reduction, but simultaneously meeting the requirements of high catalytic activity, stability, recyclability and facile preparation is highly difficult. Herein, the three‐dimensional (3D) porous magnetic polyaniline (PANI) was synthesized using phytic acid (PA) as the dopant/crosslinker, and a recyclable PANI/Ag NPs nanocomposite (PMPA) was obtained through the in situ redox between PANI and AgNO3. Characterization results demonstrate that PMPA exhibits a typical 3D porous structure constructed by coral‐like PANI framework with well‐dispersed Ag NPs (10–20 nm) firmly anchored. The PMPA can efficiently catalyze the 4‐nitrophenol (4‐NP) reduction, with a reaction rate constant of 9.5 × 10−3 s−1 (and 1067.4 s−1 g−1), which is highly competitive to the previously reported high‐performance Ag NPs catalysts. This is probably due to the favorable mass/electron conduction of 3D porous structure and strong interaction between PA and Ag. Moreover, the magnetism renders PMPA recyclability via a simple magnetic attraction, and the reaction rate constant remains at a high level after six reuse cycles, up to 4.8 × 10−3 s−1. This work highlights the important role of 3D porous PANI in structure of Ag NPs nanocomposites, and paves a new way to develop recyclable catalysts with facile preparation and high catalytic performance.Highlights Facile synthesis via in situ reaction between 3D porous PANI and AgNO3. Stable dispersion and strong anchor attributed to phytic acid. Conductive porous structure to facilitate mass/electron transportation. Outstanding catalytic performance for 4‐NP reduction and recycle by magnetism.

Improving the optical, photoluminescence, and electrical properties of PEO/NaAlg-WO3 nanocomposites for optoelectronic and nanodielectric applications

Nanocomposites based on polyethylene oxide (PEO)/Sodium Alginate (NaAlg) with varying content of tungsten trioxide nanoparticles (WO3 NPs) have been synthesized by using a green solvent casting method. Through the use of X-ray diffraction (XRD), Fourier transforms infrared (FTIR), and Ultraviolet–visible spectroscopy (UV–Vis.), the interaction of mixed components has been evaluated. Studies using spectroscopy have shown that WO3 nanoparticles and the blend's component parts interact strongly at their interfaces. XRD confirms the increasing amorphous propensity of the PEO/NaAlg film with increasing nanofiller loading. FTIR implies the development of molecular complex of the polymer with the nanofiller. From UV–Vis analysis, Tauc's relation was used to specify the direct and indirect bandgap energy. The Eg (direct) of pure PEO/NaAlg was considerably decreased from 4.23 to 3.04 eV by adding 2.0 wt% of WO3 NPs. The fluorescence for various WO3 NPs concentrations in PEO/NaAlg blend films was analyzed. The PEO/NaAlg blend's fluorescence intensity decreased with increased doped with WO3 NPs. The films made of nanocomposites also had their dielectric behavior and electrical conductivity examined. In contrast to the electrical conductivity (AC), the dielectric constant and dielectric loss of PEO/NaAlg-WO3 nanocomposites drop as the frequency of the electric field rises. The investigation revealed that an increase in WO3 concentration led to a corresponding rise in the nanocomposites' dielectric loss and dielectric constant values. The fabricated system of PEO/NaAlg-WO3 NPs nanocomposites films showing improved in AC conductivity and dielectric characteristics and could be suggested in optoelectronic and nanodielectric devices.

Optical, and electrical conductivity properties of ZnO and TiO2 nanoparticles scattered in PEO-PVA for electrical devices

Polyvinyl alcohol (PVA)/Polyethylene oxide (PEO) has been blended and doped with zinc oxide and titanium oxide nanoparticles. Different concentration of the prepared ZnO and TiO2 NPs make a change in PVA/PEO- ZnO/TiO2 NPs nanocomposites films improve the characterization of PVA/PEO. XRD scans show two broad peaks at about 18.8° and 21.95° for PVA/PEO blend. XRD scans show of PVA/PEO- ZnO/TiO2 NPs nanocomposites films obtain the hexagonal structure of ZnO and the anatase phase of TiO2 NPs. The addition of dopants in the PVA/PEO blend results in a reduce in degree of crystallinity compared to the pure blend. This is evident from the decrease in the crystallinity index (Xc value) from 37.25 to 22.31. This reduction in crystallinity can have implications for the material's opticla, thermal, and electrical properties, and should be considered when evaluating its suitability for specific applications. FT-IR results show changes in intensity of bands that could be assigned to the strong interaction between PVA/PEO and ZnO/TiO2 nanoparticles. The Egopt values reduced by raising laser ablation time due to unstructured defects that enhanced the density of localized states in the band gap, dropping from 4.72 eV to 3.0 eV for direct transitions and from 3.05 eV to 2.35 eV for indirect transitions. It undergoes complete decomposition at a higher temperature, resulting in a mass percentage of 45 ± 0.3 wt%. In comparison, the pure polymer blend sample has a lower mass percentage of 33 ± 0.03 wt% during the same temperature range. The fabricated system of PVA/PEO- ZnO/TiO2 NPs nanocomposites films showing improved in AC conductivity and dielectric characteristics and could be suggested in electrical applications.

Nb2C MXene self-assembled Au nanoparticles simultaneously based on electromagnetic enhancement and charge transfer for surface enhanced Raman scattering

Recent years, two-dimensional transition metal carbonitrides (MXene) have attracted much attention in the field of surface-enhanced Raman scattering (SERS). However, the relatively low enhancement of MXene is a major challenge. Herein, Nb2C-Au NPs nanocomposites were prepared by electrostatic self-assembly method, which have a synergistically conjugated SERS effect. The EM hot spots of Nb2C-Au NPs are significantly enlarged and expanded, while the surface Fermi level is decreased. This synergistic effect could improve the SERS performance of the system. Consequently, for the dye molecules CV and MeB, the detection limits reach 10−10 M and 10−9 M, respectively, while for biomolecule adenine, the detection limit is as low as 5 × 10−8 M. The results also show the good concentration-dependent linearity, uniformity, reproducibility and stability of SERS substrate. Nb2C-Au NPs could be a fast, sensitive and stable SERS platform for label-free and non-destructive detection. This work may expand the application of MXene based materials in the field of SERS.

Harmine loaded Au@MSNs@PEG@Asp6 nano-composites for treatment of spinal metastasis from lung adenocarcinoma by targeting ANXA9 in vivo experiment.

Annexin A9 (ANXA9) has been proved to be concerned with cancer development. However, to explore the clinical consequences of ANXA9 in lung adenocarcinoma (LUAD), especially its correlation to spinal metastasis (SM) has no in-depth study. The study was expected to elucidate the mechanism of ANXA9 in regulating SM of LUAD and create a productive nano-composites delivery system targeting this gene for treatment of SM. Harmine (HM), a β-carboline extracted from the traditional Chinese herb Peganum harmala, loaded Au@MSNs@PEG@Asp6 (NPS) nano-composites were synthesized. Bioinformatics analysis and clinical specimens' tests were used to verify the association between ANXA9 and prognosis of LUAD with SM. The immunohistochemistry (IHC) was employed to detect the expression levels of the ANXA9 protein in LUAD tissues with or without SM, and its significance in clinic was also explored. ANXA9‑siRNA was applied to investigate the molecular mechanism of ANXA9 in tumor behaviors. The HM release kinetics was detected by high performance liquid chromatography (HPLC) method. The cellular uptake efficiency of nanoparticles by A549 cells was observed by fluorescence microscope. Antitumor effects of nanoparticles were assessed in the nude mouse model of SM. The genomic amplification of ANXA9 was prevalent in LUAD tissues and closely associated with poor outcome and SM (P<0.01). The experimental result manifested that high expression of ANXA9 could lead to wretched prognosis and ANXA9 was an independent risk factor for survival (P<0.05). After impeding expression of ANXA9, the proliferation and metastatic ability of tumor cells obviously decreased, and expression of matrix metallopeptidase 2 (MMP-2) and matrix metallopeptidase 9 (MMP-9) were considerably downregulated, while the expression of associated oncogene pathway were downregulated (P<0.01) as well. The synthesized HM-loaded NPS nano-composites could target to cancer and response to reactive oxygen species (ROS) to release HM slowly. Notably, in comparison to free HM, the nano-composites showed excellent targeting and anti-tumor effects in the A549 cell-bearing mouse model. ANXA9 may serve as a novel biomarker for predicting poor prognosis in LUAD, and we provided an efficient and targeting drug delivery nano-composites system for precise treatment of SM from LUAD.

Electrochemical aptasensor based on PEI-Fe-MOF/Au@Ag NPs nanocomposites for streptomycin detection in dairy products

Streptomycin (STR) residues in dairy products could cause serious health risks for human or affect the quality of the dairy products fermented by lactic acid bacteria, thereby resulting in economic losses. Thus, STR detection methods need to be developed quickly, simply, and sensitively. In this study, polyethyleneimine (PEI)-functionalized NH2-MIL-101(Fe) (PEI-Fe-MOF) was characterized and found to exhibit an enhanced electrochemical characteristics, when compared to Fe-MOFs. Au@Ag core-shell NPs could further amplify its electrochemical signal. Based on the PEI-Fe-MOF/Au@Ag NPs nanocomposites, we have developed a novel electrochemical aptasensor to detect STR rapidly. When detected under optimal conditions, a wide linear range between 0.1 and 200 nM was observed for the aptasensor with a detection limit of 0.033 nM. Furthermore, the developed aptasensor has been satisfactorily applied for the rapid STR detection in dairy products with recoveries ranging from 98.2% to 110.1%. Therefore, our method can be considered a new effective method for the rapid detection of STR in dairy products.

Optical, thermal and electrical characterization of PEO/CMC incorporated with ZnO/TiO2 NPs for advanced flexible optoelectronic technologies

The optical, thermal, and electrical properties of a blend of polyethylene oxide (PEO) and carboxymethyl cellulose (CMC) are examined in the current work in relation to the effects of zinc oxide (ZnO) and titanium dioxide (TiO2) nanoparticles. To create hybrid ZnO/TiO2 NPs nanocomposites with a PEO/CMC matrix, the solution casting method was utilized. The XRD study results demonstrate that the nanocomposite films' crystallinity decreases with increasing ZnO/TiO2 NP concentrations. FT-IR spectra reveal the interaction between metal oxide NPs and the PEO/CMC composite. UV/Vis analytical spectroscopy was used to calculate the optical properties, such as the energy gap (Eg), refractive index (n), and the number of carbon atoms (M). The inclusion of 7 wt%ZnO/TiO2 NPs decreased the polymer matrix's allowed direct energy gap from 3.68 to 2.81 eV. The AC conductivity results show that the σdc of the nanocomposite samples decreases with increasing ZnO/TiO2 NPs concentrations. The σdc of the final sample (PEO/CMC@7 wt% ZnO/TiO2) was 5.18 × 10−7Scm−1. According to exponential factor (S) results, the dominates conduction mechanism is correlated barrier hopping (CBH) with non-Debye relaxation processes. Space charge polarization was demonstrated by large ε′ values in the low-frequency dielectric properties, whereas an increase in energy loss may be related with a larger εʹ' value in the composite samples. These results prove that these nanocomposites can be used in a variety of energy-related devices, such as flexible capacitors, and energy storage systems.

Synthesis and characterization of sodium alginate/polyvinyl alcohol/zinc oxide/iron oxide nanocomposites for electrochemical applications

AbstractPolymer nanocomposites films, based on sodium alginate (NaAlg) and polyvinyl alcohol (PVA) complexed with zinc oxide nanoparticles (ZnO NPs) and iron oxide nanorods (Fe3O4 NRs) as nanofiller, were prepared by solution casting technique. Different techniques were used to describe the prepared films. XRD and FTIR were used to pinpoint the complexation of the nanofiller with the polymer mixture. The XRD investigation verified the existence of the crystalline peaks of ZnO/Fe3O4 NPs in the polymeric matrices. The average particle size of nanocomposite was 23 nm. TEM image of the ZnO nanopowder confirming the spherical form of nanoparticles with average size 30 nm. The TEM image of Fe3O4 NRs reveals the free nanorods are around 9–23 nm in diameter and 130–350 nm in length. Peak positions and intensity variations in the FTIR absorption spectra are observed when the concentration increases from 2 to 8 wt% of ZnO NPs/Fe3O4 NRs. AC conductivity showed that the NaAlg/PVA‐(8 wt%) ZnO/Fe3O4 NPs nanocomposites have higher electrical conductivity than NaAlg/PVA blend. For samples of 8% ZnO/Fe3O4, the of nanocomposites reached 3.66 × 10−8 S cm−1. ZnO/Fe3O4 nanoparticles considerably improved the nanocomposites' ability to conduct electricity. For the development of functional composite materials for the manufacture of electrical devices, sensors, and high‐energy storage capacitors, the enhanced characteristics of synthesized NaAlg/PVA‐ZnO/Fe3O4 nanocomposites can be helpful.

Enhancement in optical, thermal and electrical properties of Polyvinyl pyrrolidone/ polyethylene oxide matrix-based nanocomposites for advanced flexible optoelectronic technologies considering nanoceramic zinc oxide/titanium dioxide filler

Polyvinyl pyrrolidone (PVP) and polyethylene oxide (PEO) hybrid nanocomposites with varying zinc oxide (ZnO) and titanium dioxide (TiO2) concentrations were created using the solution casting process. The influence of ZnO/TiO2 nanoparticles on the optical, thermal, and electrical properties of the pure PVP/PEO composite was investigated and discussed. The results of the XRD analysis show that as ZnO/TiO2 NPs concentrations increases, the crystallinity of the nanocomposite films decreases. The interactions between the ZnO/TiO2 nanoparticles and the PVP/PEO polymeric chain is shown by FT-IR spectra. Peak positions and intensity variations in the FT-IR absorption spectra are observed when the concentration increases from 0.5 to 2 wt.% of ZnO/TiO2 NPs. The optical parameters including energy gap (Eg), refractive index (n), and Urbach energy (Eu) for PVP/PEO/ZnO/TiO2 nanohybrid samples were calculated using UV/Vis analytical spectroscopy. The energy gap narrows when ZnO/TiO2 nanohybrid concentration rises, as shown by the optical absorption spectra. The allowed indirect energy gap of the polymer matrix was reduced from 3.72 to 1.94 eV by the addition of 2 wt.% ZnO/TiO2 NPs. The TGA curve shows that the ZnO/TiO2 nanohybrid enhanced the thermal stability of the samples. As the concentration of metal oxides increased, the activation energy (Ea) decreased. AC conductivity showed that the PVP/PEO -(2 wt.%) ZnO/TiO2 NPs nanocomposites have higher electrical conductivity than PVP/PEO. For samples of -(2 wt.%) ZnO/TiO2, the σdcof nanocomposites reached 4.64×10−5Scm−1. Exponential factor (S) results show that in nanocomposite samples with non-Debye relaxation processes, the correlated barrier hopping mechanism (CBH) is dominant. High values of ε' at low-frequency in the dielectric characteristics demonstrated space charge polarization, whereas higher values of ε" in the composite samples could be associated with an increase in energy loss. These results illustrate the appropriateness of these nanocomposites for variety of uses, including flexible capacitors, battery separators, and energy storage devices.

Tuning optical, dielectric, and electrical properties of Polyethylene oxide/Carboxymethyl cellulose doped with mixed metal oxide nanoparticles for flexible electronic devices

In the current study, cast synthesis was used to quickly create flexible composite films made of PEO (Polyethylene oxide), CMC (Carboxymethyl cellulose), and ZnO/GO NPs as nanofiller. XRD and FTIR spectroscopy were used to examine the structure of the nanocomposites. They demonstrated the PEO/CMC blend's effective interaction with the ZnO/GO NPs. The UV–Vis optical absorbance was used to estimate the optical properties of pure PEO/CMC blend and nanocomposites films, including energy band gap and Urbach energy. Calculations were made to determine optical properties such as the Urbach energy and energy band gap. With an increase in ZnO/GO NPs weight percentage, the energy band gap decreased, and Urbach energy increased. The ionic conductivity of the polymer nanocomposites has been examined using AC-impedance spectroscopy. The greater ionic conductivity (σ) ∼10–9 S/cm is obtained for PEO/CMC film, and it was increased to ∼ 10–7 S/cm at room temperature by adding 8% ZnO/GO nanofiller. While the AC electrical conductivity increases with frequency, the values of ε′ and ε″ of PEO/CMC- ZnO/GO NPs nanocomposites reduce as the frequency of the electric field increases. It was discovered that the concentration elevation of ZnO/GO NPs increased the values of ε′ and ε″ in the nanocomposites. PEO/CMC–8wt%ZnO/GO nanocomposite having improved optical, dielectric, and electrical properties can be used in various industrial applications such as electric and optoelectronic devices.

A love-mode surface acoustic wave aptasensor with dummy fingers based on monolayer MoS2/Au NPs nanocomposites for alpha-fetoprotein detection.

The detection of cancer markers still has shortages of low sensitivity, time-consuming operation, the use of unstable and expensive antibodies. In this work, a novel Love-mode surface acoustic wave (LSAW) aptasensor with dummy fingers based on the monolayer molybdenum disulfide/gold nanoparticles (monolayer MoS2/Au NPs) was developed for the highly sensitive and rapid determination of alpha-fetoprotein (AFP) in serum. Interdigital electrodes (IDTs) with dummy fingers were designed and applied to improve the acoustic characteristic of the LSAW aptasensor. The less energy dissipation and wave-front distortion of the LSAW aptasensor were confirmed by COMSOL simulation and test results. The newly-developed sensing film monolayer MoS2/Au NPs/Apt/6-mercaptohexanol (MCH) was applied for the specific detection of AFP and significantly improved the sensitivity of the LSAW aptasensor. The excellent performance of the LSAW aptasensor allowed the sensitive and rapid detection of AFP in serum in the range of 0.01 ⁓ 100ng/mL with a low detection limit of 4.79pg/mL. Additionally, the proposed LSAW aptasensor exhibited excellent selectivity, long-term stability, and reproducibility, and could be used to detect other cancer biomarkers.

Biocompatible POSS-gold nanocomposites synthesized by laser ablation in ethanol

Polymer-gold nanoparticle nanocomposites based on POSS polymer with a thiol group was obtained by laser ablation in liquids (LAL). Laser ablation of a gold target in a solution of ethanol and POSS-thiol produced high purity nanocomposites of POSS decorated with gold nanoparticles (Au NPs) in colloidal suspension. TEM characterization showed spherical geometry of the Au NPs, mainly smaller than 60 nm. The UV–Vis-NIR spectroscopy exhibited the typical absorbance spectra for spherical Au NPs in the visible range (520–550 nm) related to plasmonic behavior. POSS-Au NPs nanocomposites exhibited an improvement in the colloid stability, absorbance peak and reproducibility, compared to the NPs without POSS-thiol. The optimal values were found for Au NPs synthesized in a POSS-thiol ethanol solution at 0.0168 mM. The low cytotoxic activity in human gingival fibroblasts (HGF) suggest the biocompatibility of the nanocomposite. The optical properties and biocompatibility of the nanocomposite shows its use viability for applications as biosensors based in optical response.

Kappa-Carrageenan Crosslinked Magnetic Folic Acid-Conjugated Chitosan Nanocomposites for Arginase Encapsulation, Delivery and Cancer Therapy

In this study, the Aspergillus niger L-arginase was expressed in Pichia pastorise and immobilized on Kappa-carrageenan crosslinked magnetic folic acid-conjugated chitosan nanoparticles (magnetic-FA/CTS NPs). L-arginase gene was isolated and cloned in pGAPZ[Formula: see text]A plasmid and transformed in P. pastoris. The purified L-arginase was loaded on magnetic-FA/CTS NPs nanocomposites and the structure of the synthesized nano-carriers was investigated using SEM, FT-IR and DLS techniques. Prepared formulations showed high encapsulation efficiency (91.93%). In vitro release and cytotoxic studies were performed at different pH (pH of 4–8) and against Molt-4 cancer cell line, respectively.

Label-Free and Highly-Sensitive Detection of Ochratoxin A Using One-Pot Synthesized Reduced Graphene Oxide/Gold Nanoparticles-Based Impedimetric Aptasensor.

Ochratoxin A (OTA) primarily obtained by the genera aspergillus and penicillium, is one of the toxic substances for different organs and systems of the human body such as the kidney, liver, neurons and the immune system. Moreover, it is considered to cause tumors and fetal malformation even at a very low concentration. Fast and sensitive assay for detection of OTA at ultralow levels in foods and agricultural products has been an increasing demand. In this study, a new label-free electrochemical biosensor based on three-dimensional reduced graphene oxide/gold nanoparticles/aptamer for OTA detection was constructed. The 3D-rGO/Au NPs nanocomposites were firstly synthesized using a one-pot hydrothermal process under optimized experimental conditions. The 3D-rGO/Au NPs with considerable particular surface area and outstanding electrical conductivity was then coated on a glass carbon electrode to provide tremendous binding sites for -SH modified aptamer via the distinctive Au–S linkage. The presence of OTA was specifically captured by aptamer and resulted in electrochemical impedance spectroscopy (EIS) signal response accordingly. The constructed impedimetric aptasensor obtained a broad linear response from 1 pg/mL to 10 ng/mL with an LOD of 0.34 pg/mL toward OTA detection, highlighting the excellent sensitivity. Satisfactory reproducibility was also achieved with the relative standard deviation (RSD) of 1.393%. Moreover, the proposed aptasensor obtained a good recovery of OTA detection in red wine samples within the range of 93.14 to 112.75% along with a low LOD of 0.023 ng/mL, indicating its applicability for OTA detection in real samples along with economical, specific, susceptible, fast, easy, and transportable merits.

Core-shell ZnO@Cu2O encapsulated Ag NPs nanocomposites for photooxidation-adsorption of iodide anions under visible light

Iodide anion (I−) is one of the most-problematic radioactive nuclides in used nuclear fuel due to its intrinsic characteristics of a high toxicity and environmental mobility. Therefore, effective and selective elimination of I− from nuclear contaminated solution is highly beneficial for the pollution remediation purposes in the development of nuclear power, but is of significant challenge owing to the extreme conditions of the high acidity, strong ionizing radiation field and high concentration of competing anions. Herein, a novel core–shell ZnO@Cu2O (ZC) encapsulated Ag nanoparticles (Ag NPs) nanocomposites have been fabricated via a facile one step self-assembly process and an environmentally friendly technique. The as-fabricated ZnO@Ag@Cu2O (ZAC) nanocomposites were characterized and applied to capture of I− from aqueous solution. Adsorption studies revealed that the ternary nanocomposites showed fast removal kinetics, high photooxidation-adsorption capacity (up to 217.4 mg g−1 at pH = 3 for ZAC-2), satisfactory selectivity and high acidity resistance. Furthermore, the nanocomposites also exhibited a good reusability, as no significant change in the uptake capacity was observed even after five adsorption-regeneration cycles. Inspired by the superior features, a possible mechanism (chemical adsorption coupled with photooxidations) was proposed based on XRD, XPS and Raman spectra analysis for the pre- and post-adsorbed samples as well as the detailed adsorption experimental evidence.