Eco-Friendly Fumed Nanosilica@Nanodiamond Hybrid Nanoparticles with Dual Sustainable Self-Healing and Barrier Anticorrosive Performances in Epoxy Coating.

Fumed nanosilica@nanodiamond attached by APTES [(3-aminopropyl) triethoxysilane], named FSiO2@sND, was examined as an efficient anticorrosive nanohybrid for epoxy coating. Compared with fumed nanosilica (FSiO2), nanodiamond (ND) moderated the hydrophilic nature of FSiO2@sND and offered additional functional groups to the nanohybrid, i.e., carboxylic groups of ND and functional groups of APTES, while retaining the eco-friendly nature of FSiO2 in the hybrid nanoparticle. The hybrid nanoparticle showed pH-sensitive release behavior in which APTES is released considerably in an alkaline medium, acting as an efficient corrosion inhibitor. A thorough electrochemical impedance spectroscopy (EIS) study of scratched coatings in a 3.5% NaCl solution disclosed that FSiO2@sND nanoparticles (at 0.33 wt % loading) conferred significant active/self-healing anticorrosion properties for the epoxy coatings, thanks to the release of APTES and the presence of carboxylic groups of ND taking part in forming a stable protective film on the substrate. Accordingly, epoxy/FSiO2@sND coatings showed a corrosion improvement efficiency of 138% at an optimum immersion time of 5 h, which was higher than the 96% improvement for epoxy/FSiO2 coating. Epoxy/FSiO2@sND intact coating showed much higher low-frequency impedance, i.e., 7.23 Ω·cm2, compared with epoxy/FSiO2 coating, i.e., 5.44 Ω·cm2, and neat epoxy coating, i.e., 5.71 Ω·cm2, after 22 weeks of immersion in salty solution. This result along with a detailed analysis of EIS data for intact coatings suggested that FSiO2@sND brought about strong barrier anticorrosive performance for epoxy coating. Such behavior was attributed to improved dispersion of nanohybrid in the epoxy matrix, enhanced cross-link density of the epoxy matrix, and improved coating/substrate adhesion caused by APTES and the carboxylic groups of ND.

A dually emissive MPA-CdTe QDs@N, S-GQD nanosensor for sensitive and selective detection of 4-nitrophenol using two turn-off signals.

4-Nitrophenol (4-NP) is an extremely poisonous and carcinogenic phenol that poses serious health issues to humans. Therefore, it becomes highly demanded and urgent to determine 4-NP in water samples. In this study, we developed a facile and effective dually-emissive nanosensor containing simply mixed CdTe quantum dots (CdTe QDs) and N, S modified graphene quantum dots (N, S-GQDs) for 4-NP. The synthesized CdTe QDs and N, S-GQDs exhibited excitation-independent emission located at 540 nm and 420 nm, respectively. The nanosensor displayed two turn-off fluorescent signals when exposed to 4-NP. The degree of quenching varied depending on the excitation wavelength range used, which can be explained by the quenching phenomenon based on the inner filter effect (IFE). Moreover, analysis of the recorded excitation-emission matrix (EEM) data using the parallel factor analysis (PARAFAC) technique revealed a negative emission spectrum corresponding to non-emissive 4-NP. On the other hand, the species with no peak in fluorescence data had a negative spectrum as the PARAFAC emission loading. Under the optimized conditions, the CdTe QDs@GQD nanosensor achieved fast and highly sensitive detection of 4-NP within the concentration range of 0.0-30.0 µM, with a detection limit of 0.52 µΜ.

Production of Innovative Essential Oil-Based Emulsion Coatings for Fungal Growth Control on Postharvest Fruits.

This work assessed the antimicrobial potential of natural essential oils (EOs) from cinnamon (CEO), zataria (ZEO), and satureja (SEO), applied natively or as coatings against Penicillium expansum and Botrytis cinerea during both in vitro and in vivo (on apple fruits) experiments. The induced inhibitory effect towards fungal growth, as a function of both EO type and concentration (75-1200 µL/L), was preliminarily investigated to select the most suitable EO for producing bacterial cellulose nanocrystals (BCNCs)/fish gelatin (GelA)-based emulsions. CEO and ZEO exhibited the best performances against P. expansum and B. cinerea, respectively. None of the pristine EOs completely inhibited the fungal growth and "disease severity", properly quantified via size measurements of lesions formed on fruit surfaces. As compared to pristine CEO, coating emulsions with variable CEO concentration (75-2400 µL/L) curbed lesion spreading on apples, owing to the controlled CEO release during a 21-day temporal window. The strongest effect was displayed by BCNCs/GelA-CEO emulsions at the highest CEO concentration, upon which lesions on fruit skins were barely detectable. This work demonstrated the capability of EOs embedded in BCNCs/GelA-based nanocapsules to efficiently slow down microbial spoilage on postharvest fruits, thus offering viable opportunities for developing innovative antimicrobial packaging systems.

Synthesize and multi-spectroscopic studies of zinc-naproxen nanodrug as DNA intercalator agent.

The zinc-naproxen complex as a nano-drug (NanoD) was synthesized successfully via effective ultrasound-assisted processes. The chemicophysical properties of the NanoD were determined using FT-IR, XRD, SEM, DLS, and EDX mapping analyses. The results confirmed the formation of the 55 nm NanoD laminates. The interaction of the obtained NanoD with calf thymus deoxyribonucleic acid (CT-DNA) was studied as well. Structural and topography changes of DNA in interaction with the NanoD were investigated by atomic force microscopy (AFM). The results of electronic absorption spectroscopy, the DNA-viscosity studies, and competition fluorescence spectroscopy showed that CT-DNA binds to the NanoD through the intercalative binding mode. The data of AFM analysis indicated swollen CT-DNA upon interaction with the NanoD. The in vitro investigation of cytotoxicity of the NanoD on HT-29, Hep G2, and B16-F10 cancer cells as well as normal HFF-1 cells. The obtained results demonstrated high cytotoxicity activity of the NanoD than that of cisplatin in the HT-29 cell line, especially at lower concentrations. On the B16-F10 cell line at lower concentrations (up to 8 µg mL-1), it is comparable to cisplatin and on the Hep G2 cell line and normal HFF-1 cell line at all concentrations, cytotoxicity of cisplatin is more than NanoD.

Molecularly imprinted polymer grafted on paper and flat sheet for selective sensing and diagnosis: a review.

Molecularly imprinted polymers are efficient and selective adsorbents which act as artificial receptors for desired compounds with the ability to recognize the size, shape, and functional groups of the compounds simultaneously. A molecularly imprinted polymer is prepared by the polymerization of functional monomers around a template (analyte) molecule. Afterward, the removal of the template from the polymer matrix leaves a selective cavity behind. The fabrication and development of molecularly imprinted polymers grew rapidly, due to their low cost, simple preparation, selectivity, sensitivity, and stable physicochemical properties. Traditionally, molecularly imprinted polymers can be synthesized using two main methods, namely bulk and surface imprinting. For more efficient use of the latter method, researchers have developed molecularly imprinted polymers grafted on the solid-phase matrix (substrate). This grafting technique would be particularly useful for surface imprinting of macromolecules, such as proteins. Cellulose fibers of papers with unique properties such as being abundant, retaining a porous structure, having good adsorption properties, and possessing hydroxyl groups naturally have gained much attention as substrate. The goal of this review is to introduce molecularly imprinted polymer-grafted or molecularly imprinted polymer-coated paper, as an interesting, simple, and efficient method in the detection and separation of small and large molecules. Therefore, in the present paper, several recent preparation techniques and applications of molecularly imprinted polymer-grafted paper are reviewed and discussed in detail. Green, cost-effective, selective, and sensitive paper-based sensor prepared via grafting molecularly imprinted polymer on paper surface with the potential use for online detection trace of analytes in the point-of-care testing.

Control of nectarine fruits postharvest fungal rots caused by Botrytis Cinerea and Rhizopus Stolonifer via some essential oils.

Nectarines (Prunus persica L. Bath) are very sensitive fruit to fungal infection. Today, the control of postharvest fruit diseases with essential oils (EOs) has been significantly noticed as a novel trend in biological preservation. In this study, volatile compounds of Cinnamon zeylanicum (CEO), Zataria multiflora (ZEO), and Satureja khuzestanica (SEO) were analyzed by Gas Chromatography-Mass spectroscopy. Also, the in vitro antifungal activities of EOs against Botrytis cinerea and Rhizopus stolonifer were evaluated at different concentrations. The in vivo antifungal activity of these EOs on artificially infected nectarine fruits was also considered. The major components were Thymol (32.68%) and Carvacrol (30.57%) for ZEO, cinnamaldehyde (80.82%) for CEO, and carvacrol (38.43%) for SEO. The application of different concentrations showed a decreasing trend in the fungus radial growth in all EOs. In the in vitro experiments, ZEO and CEO exhibited more significant mycelial inhibition results and reduction of the IC50, MIC and MFC values against Botrytis cinerea and Rhizopus stolonifer, respectively. However, in the in vitro experiments, none of the treatments were capable of completely inhibiting the growth of the fungi. According to the results of this study, ZEO and CEO could reduce the damage caused by these fungi.

Removal of methylene blue via bioinspired catecholamine/starch superadsorbent and the efficiency prediction by response surface methodology and artificial neural network-particle swarm optimization.

This paper demonstrates coupling of the artificial neural network (ANN) technique with the particle swarm optimization (PSO) method and compares the performance of ANN-PSO with response surface methodology (RSM) in prediction of the adsorption of methylene blue (MB) by a novel bio-superadsorbent. To this, a starch-based superadsorbent was synthesized using acrylic acid and acryl amid polymers and then catecholamine functional groups were combined onto the surface with oxidative polymerization of dopamine. The adsorption of MB was considered as a function of pH, dye concentration, and contact time. The best topology of the ANN was found to be 3-7-1, and prediction model of the adsorption capacity was demonstrated as a matrix of explicit equations. ANN-PSO is more accurate than RSM. The results revealed that the root-mean-square error, correlation coefficient, and normalized standard deviation for the ANN-PSO are 22.46, 0.99, and 16.83, respectively, while for RSM are 82.89, 0.98, and 65.41, respectively.

Bioinspired catecholamine/starch composites as superadsorbent for the environmental remediation.

Focusing on the encouraging properties of starch-based composite materials, starch­g­(acrylic acid­co­acrylamide) superabsorbent was synthesized using solution polymerization method, and then the catecholamine functional groups were introduced on to pore surface of the absorbent via oxidative polymerization of dopamine (DA). The adsorbent was optimized in terms of the monomers' mass ratio and synthesis conditions, and characterized by different characterization techniques. The polydopamine (PDA) coating thickness was estimated using transmission electron microscopy (TEM) image and it was found to be 83 nm. The bimodal mesoporous adsorbent with 5914.66% swelling ratio bearing micropores with a specific surface area of 2.8031 m2 g-1 was used for the adsorption of methylene blue (MB) as a model water pollutant dye. The maximum adsorption capacity was obtained 2276 mg g-1 at pH 9 and within 100 min. The adsorbent with unprecedented super high adsorption capacity can be encouraging from different environmental remediation points of view.

Bimodal porous silica microspheres decorated with polydopamine nano-particles for the adsorption of methylene blue in fixed-bed columns.

Bimodal meso/macro-porous silica microspheres (MSM) were synthesized by a modified sol-emulsion-gel method and then the surface was coated with polydopamine (PDA) nano-particles of 39nm in size. Focusing on the encouraging properties of the synthesized adsorbent, such as high specific surface area (612.3m(2)g(-1), because of mesopores), fast mass transfer (0.9-2.67×10(-3)mLmin(-1)mg, because of macropores), and abundant "adhesive" functional groups of PDA, it was used for the removal of methylene blue (MB) from aqueous solution in a fixed-bed column. The effect of different parameters such as pH, initial concentration, and flow rate was studied. The results revealed that an appropriate sorption condition is an alkaline solution of MB (e.g., pH 10) at low flow rate (less than 5mLmin(-1)). Furthermore, the compatibility of the experimental data with mathematical models such as Thomas and Adams-Bohart was investigated. Both of the models showed a good agreement with the experimental data (R(2)=0.9954-0.9994), and could be applied for the prediction of the column properties and breakthrough curves. Regeneration of the column was performed by using HCl solution with a concentration of 0.1M as an eluent.

Robust and selective nano cavities for protein separation: an interpenetrating polymer network modified hierarchically protein imprinted hydrogel.

In the present work, we report a novel method for the reinforcement of hierarchically structured molecularly imprinted polymer (MIP) for the separation of human serum albumin (HSA) and immunoglobulin G (IgG) proteins under pressure driven flow conditions. The template proteins (HSA or IgG) were first physically adsorbed at their isoelectric point on the surface of wide pore silica particles. Thereafter, the pore system was filled with a monomer solution and polymerized to form a lightly crosslinked polyacrylamide network covering the protein template. In order to enhance the rigidity of the hydrogels, different type of crosslinkers such as ethylene glycol dimethacrylate (EGDMA), 3,4-dihydroxyphenethylamine (DA) and methylene-bis-acrylamide (MBA), at least partially interpenetrated into the initially made acrylamide base hydrogel leading to formation of an interpenetrating polymer network (IPN). Then the silica matrix was removed to leave highly porous and reinforced MIP. TGA together with FT-IR and TEM analysis supported the interpenetration of the secondary crosslinkers in the initially formed polymer matrix. The compression property of the modified hydrogels as a function of degree of swelling was in the following order: DA>EGDMA>MBA-IPN-modified hydrogel. Batch binding assay verified the capability of the IPN modified MIPs to capture the target proteins. Moreover, solid phase extraction, HPLC and SDS-PAGE revealed that the EGDMA modified MIP could selectively capture and separate the proteins from human serum or fermentation broth.

Molecularly imprinted polydopamine nano-layer on the pore surface of porous particles for protein capture in HPLC column.

Bio-inspired Human Serum Albumin (HSA) imprinted polydopamine nano-layer was produced through oxidative polymerization of dopamine on the pore surface of HSA modified porous silica particles. The coating thickness was controlled by the reaction time and thereby varied within 0-12 nm. The samples were characterized by elemental analysis, FT-IR, DSC, SEM, TEM, TGA, physisorption and thermoporometry. The characterization confirmed the success of evolution and deposition of polydopamine layer on the silica pore surface. Batch rebinding experiment showed that the molecularly imprinted polymer (MIP) with 8.7 nm coating thickness, in comparison with the thinner and thicker coatings, displays the highest uptake of the target protein. The chromatographic evaluation of the materials packed in HPLC columns showed that the HSA imprinted polydopamine offers good mechanical stability and retains practically all the target protein from an HSA solution or human plasma. Affinity of the imprinting column was examined by using Bovine Serum Albumin (BSA) and Immunoglobulin G (IgG) as competitive proteins. The results showed that the template, HSA, was the most adsorbed protein by the imprinted polydopamine layer.