Casein/ferric chloride/polyvinyl alcohol composite for specific in-syringe colorimetric detection of formaldehyde in Hevea brasiliensis latex.

A new, simple, and selective colorimetric method of determining formaldehyde in Hevea brasiliensis latex was developed by using a casein/ferric chloride/polyvinyl alcohol hydrogel composite (casein/FeCl3/PVA) in a modified Leach test. Under heating, formaldehyde reacted with 8% casein in the presence of 0.1% FeCl3 and 4.3% HCl (v/v) entrapped in a 30% PVA hydrogel packed in a syringe. A purple-colored product was formed with a maximum absorbance of 525 nm. The color change was evaluated at the color detection zone indicated on the the syringe. The %magenta values were easily evaluated by using a mobile phone application and employed to determine formaldehyde content. The casein/FeCl3/PVA composite gave a readable response in a formaldehyde detection range from 0.04 to 0.80% with a linear response between %magenta and formaldehyde concentration (R2 = 0.9955). The detection limit was 0.032%, and precisions were in the range 0.67-4.94%. The casein/FeCl3/PVA composite was applied to the analysis of ammonia-preserved latex samples, and recoveries of formaldehyde from samples spiked at 0.1, 0.3, and 0.5% ranged from 81.55 to 99.51% (RSDs ≤ 5.41%). The recoveries and precision of the proposed method were comparable with those of high-performance liquid chromatography (HPLC). The developed method was also selective, showing no interference from other latex preservatives, i.e., phenol, ammonia, or tetramethylthiuram disulfide.

Simultaneous quantification of volatile fatty acids and nonvolatile organic acids in Hevea brasiliensis latex.

The current method used in latex industries to determine the volatile fatty acids contents of Hevea brasiliensis latex is steam distillation. However, the accuracy of the method has been debated for some time. We assessed the accuracy of the method and developed a new, more reliable high-performance liquid chromatographic method of determining acids in latex. The volatile fatty acids (formic, acetic, propionic, butyric, and valeric acids) and nonvolatile organic acids (oxalic, malic, lactic, citric, and succinic acids) in latex are directly determined simultaneously for the first time with high sensitivity and without losses during sample preparation. To avoid errors from derivatization, an acid-resistant Prevail HPLC column and a gradient mobile phase of 25 mM potassium dihydrogen phosphate (pH 2.5) and acetonitrile were employed. Under optimum conditions, the calibrations of both types of acids demonstrated satisfactory correlation coefficients of  ≥0.990, with limits of detection ranging from 0.02 to 395 mM. The developed method demonstrated the profiles of acids in field and concentrated latex of the same batch. Moreover, the evolution of the profiles of all studied acids in both types of latex during a 3-month period was also revealed.

Fluorescence enhancement in an over-etched gold zero-mode waveguide.

The fluorescence enhancement in an over-etched gold zero-mode waveguide (ZMW) was investigated through both numerical simulation and experiments. Using Cy3 and Cy5 as the fluorescent probes, the simulation showed that the undercut not only enhances the fluorescence signals of both fluorophores, but also greatly improves the radial uniformity of the excitation fields in the ZMW. Furthermore, using a focused-ion-beam tool, we fabricated Au-ZMW arrays with different radius and undercut. The fluorescence enhancement per molecule and the effective excitation volume of the Au-ZMW were then measured as functions of its radial size and over-etching depth by using fluorescence correlation spectroscopy. It was found that the undercut can significantly enhance the fluorescence signal per molecule in the ZMW, but it also slightly increased the excitation volume. Decreasing the radial size of the ZMW can efficiently reduce the excitation volume and also further enhance the fluorescence per molecule. These results together indicate that combining the undercut and reduction of radius of the ZMW can serve as a simple and effective way to essentially improve the performance of an Au-ZMW for single molecule fluorescence detection.

Nearly monodispersed MoS2 hierarchical architectures as superior anodes for electrochemical lithium-storage.

In this paper, we developed a facile approach to synthesize well-dispersed 3D hierarchical porous MoS2 architectures with assistance of polyacrylate and demonstrated their applications in lithium ion batteries (LIBs). It was confirmed that the uniform flower-like MoS2 architectures were assembled by nanosheets comprising about ∼10 stacking layers. Polyacrylate was revealed to have a significant impact on controlling the formation of the uniform hierarchical flower-like architectures with desirable dispersity. It was believed that the polyacrylate could direct assembly of the MoS2 nanosheets into hierarchical structures and could well stabilize and disperse MoS2 architectures. Furthermore, a stable cycling capability (839 mAh g-1 at 0.1 A g-1 after 120 cycles) and superior rate ability of the MoS2 architectures were achieved as anodes for LIBs. This remarkably enhanced electrochemical property could be ascribed to their beneficial structural features and surface-dominated capacitive contribution.

Colorimetric determination of fumonisin B1 based on the aggregation of cysteamine-functionalized gold nanoparticles induced by a product of its hydrolysis.

A colorimetric method was developed for the determination of the mold toxin fumonisin B1 (FB1). It is based on the aggregation of cysteamine-capped gold nanoparticles (Cys-AuNPs). The assay involves alkaline hydrolysis of FB1 to obtain hydrolyzed fumonisin B1 (HFB1). The latter induces the aggregation of Cys-AuNPs which results in a color change from wine-red to blue-gray, best at a pH value of 9.0. A plot of absorbance ratio at 645/520 nm versus FB1 concentration is linear in the 2-8 µg kg-1 FB1 concentration range, and the detection limit is 0.90 µg kg-1. Inter-day and intra-day precisions are <6.2%, and recoveries from spiked samples ranged from 93 to 99%. The assay was successfully applied to the determination of FB1 in corn samples. It has a high selectivity over other competitive mycotoxins including aflatoxin, zearalenone, citrinin and patulin. The method is more selective than the detection of FB1 directly which may lead to false-positive errors. Graphical abstract Schematic representation of colorimetric assay of fumonisin B1 (FB1). FB1 was alkali-hydrolyzed and its product (hydrolyzed fumonisin B1) induces cysteamine-capped gold nanoparticles (Cys-AuNPs) via hydrogen bondings. The aggregation of Cys-AuNPs causes changes in color from wine-red to blue-gray.

Selective magnetic nanographene oxide solid-phase extraction with high-performance liquid chromatography and fluorescence detection for the determination of zearalenone in corn samples.

A magnetic nanographene oxide sorbent as a selective sorbent for the magnetic solid-phase extraction combined with high-performance liquid chromatography and fluorescence detection was developed and proved to be a robust method for zearalenone determination in corn samples. Optimum extraction of zearalenone (20 mg magnetic nanographene oxide sorbent, extraction for 15 min, desorption time of 15 min using 1 mL of 0.5% formic acid in methanol) resulted in low limits of detection (05 mg/L) and quantitation (0.13 mg/L) and good linearity range of 0.13-1.25 mg/L with the correlation coefficient of 0.9957. Acceptable recoveries (79.3-80.6%) with relative standard deviations below 4% and satisfactory intra- and interday precisions (2-7.4%) were achieved. Additionally, the proposed method has been proved to be good in several aspects: easily prepared sorbent with high affinity to zearalenone, convenient and fast procedure, and high extraction efficiency.

Colorimetric determination of sialic acid based on boronic acid-mediated aggregation of gold nanoparticles.

The authors describe a rapid, sensitive and selective colorimetric assay for sialic acid (SA) based on the use of gold nanoparticles (AuNPs) modified with 3-aminophenylboronic acid (3-APBA) which acts as the recognition probe for SA. 3-APBA contains amino groups and boronic acid groups through which it can assemble on citrate stabilized AuNPs. It reacts with the cis-diol groups of SA by reversible formation of a cyclic boronate ester in slightly acidic buffer. Detection involves the sequential addition of AuNPs, phosphate buffer, 3-APBA and SA in a tube, vortex mixing, acquisition of photographic images or absorption spectra, and calculation of the result. The method is simple, rapid, and does not require cumbersome steps such as the preparation of stable boronic acid functionalized AuNPs as used in colorimetric sensing of saccharides. Under the optimum conditions, the ratio of absorbances at 700 and 520 nm increases linearly in the 0.15-1.00 mM SA concentrations range, and the detection limit is 60 µM. This is comparable to the detection limit obtained in other colorimetric assays reported. Acceptable intra- and inter-day precisions of three SA concentrations (0.50, 1.00 and 2.00 mM) ranged from 1.9-4.2% and 4.2-6.4%, respectively. The efficacy of the method was demonstrated by analyzing simulated human saliva which gave recoveries ranging from 98.7-106.0%. Graphical abstract Schematic of a colorimetric method for detection of sialic acid (SA) in simulated saliva. It is based on aggregation of gold nanoparticles with 3-aminophenyl boronic acid (3-APBA) which assembles on AuNPs while the boronic acid group binds to cis-diols of SA to form a boronate ester.

Highly specific colorimetric detection based on aggregation of l-cysteine functionalized gold nanoparticles for cypermethrin in water samples.

A fast, simple, and selective colorimetric assay for quantifying cypermethrin in water samples is proposed using l-cysteine functionalized gold nanoparticles (AuNPs@Cyst). Cypermethrin is hydrolyzed by potassium hydroxide to obtain hydrolyzed cypermethrin in the form of 3-phenoxybenzaldehyde by-product (HCy). The detection strategy is based on the aggregation of AuNPs@Cyst caused by hydrogen-bonding recognition between the aldehyde group of HCy and the amine group of l-cysteine on the surface of AuNPs@Cyst. As a result, in the presence of HCy under optimal pH 7, AuNPs@Cyst aggregates within 7 min, exhibiting a distinct color change from red to blue-gray, which can be evaluated with the naked eye and UV-visible spectrophotometry. From FE-TEM image, the stable and spherical AuNPs@Cyst had an average size of 13.8 ± 1.6 nm, and from zeta potential analysis, the charge of AuNPs@Cyst was -25.04 ± 1.66 mV. The surface plasmon resonance band of dispersed AuNPs@Cyst was red shifted from 525 nm to 634 nm when AuNPs@Cyst was aggregated. The absorbance ratio (A634/A525) was linearly related to cypermethrin concentrations from 0.5 to 13.0 mg L-1. The limit of detection was 0.2 mg L-1 and precision, expressed as relative standard deviations (RSDs), ranged from 1.9 to 7.3%. In the presence of interfering pesticides (carbaryl, ethion, profenofos and abamectin), only cypermethrin produced a significantly different response, confirming the selectivity of AuNPs@Cyst. Finally, AuNPs@Cyst was applied to determine cypermethrin in water samples, achieving very satisfied recoveries (>98.6%) and RSDs lower than 6.1%.

A novel magnetite C18/paracetamol/alginate adsorbent bead for simultaneous extraction of synthetic antioxidants and bisphenol A in water samples.

A novel magnetic composite bead was synthesized using carbon 18, paracetamol and alginate (mC18/Pa/Alg). The bead was applied to simultaneously adsorb butylated hydroxytoluene, butylated hydroxyanisole, and bisphenol A from water samples by magnetic solid-phase extraction (MSPE). The adsorbed analytes were determined by gas chromatography-flame ionization detection. The morphology and composition of the bead were examined by field emission scanning electron microscopy, energy-dispersive X-ray spectrometry, X-ray diffraction analysis, Fourier transform infrared spectroscopy and Brunauer-Emmett-Teller surface analysis. The best condition of MSPE included an adsorbent bead made with 0.8% sodium alginate, a 0.3 g adsorbent dose, a sample solution pH of 7, and a desorption time of 20 min in methanol. The proposed method exhibited linearity at concentrations between 0.015 and 1.00 µg mL-1 of analytes. Limits of detection ranged from 6.86 to 9.66 ng mL-1. Recoveries from 80.3 to 100.1% were achieved with interday and intraday precisions (RSDs) of 0.4-4.3%.

Chitosan-stabilized gold nanoparticles decorated with a thiodiacetic acid nanoprobe for selective detection of arsenic(iii) in rice and water samples.

A sensitive and selective method for the detection of arsenic(iii) (As3+) based on chitosan-stabilized gold nanoparticles (CS/AuNPs) decorated with a 2,2'-thiodiacetic acid (TDA) nanoprobe was developed and used to detect and indicate the contamination of rice, drinking water and environmental water samples. AuNPs were reduced and stabilized with CS and subsequently functionalized with TDA. As3+ interacted with the carboxylate group of TDA to form an As-TDA complex, inducing the aggregation of CS/AuNPs@TDA. The aggregation of CS/AuNPs@TDA was accompanied with a change in color from red to bluish purple and a shift in surface plasmon resonance wavelength from 525 nm to 645 nm. The response for the detection of As3+ was linear at concentrations from 10 to 1000 µg L-1 with a limit of detection of 6.1 µg L-1. The method exhibited selectivity toward As3+ among various cations (As5+, Cu2+, Fe3+, Fe2+, Hg2+, Al3+, Cr3+, Cd2+, Co2+, Ni2+, Pb2+ and Zn2+) and anions (Br-, Cl-, F-, SO4 2-, NO3 - and PO4 2-). The CS/AuNPs@TDA nanoprobe was applied to detect As3+ in rice, drinking water and environmental water samples. The results were consistent with those obtained via inductively coupled plasma-optical emission spectrometry (ICP-OES). Satisfactory recoveries ranging from 88.22% to 105.74% (RSDs of 0.25-2.99%) were obtained from spiked samples.

Novel polyvinyl alcohol/gum tragacanth molecularly imprinted-electrospun nanofibers as adsorbent for selective solid phase extraction of bisphenol A.

A polyvinyl alcohol/gum tragacanth molecularly imprinted nanofiber fabricated by electrospinning (PVA/GT-MIN) was used as an efficient adsorbent for the solid phase extraction (SPE) of bisphenol A (BPA) in water samples. PVA and GT were functional polymers and BPA was the template for molecular imprinting. BPA was bound to the polymer matrix through hydrogen bonding. The SEM image of PVA/GT-MIN demonstrated a rough morphology with pores and a diameter of 501 nm. The data for the adsorption of BPA on PVA/GT-MIN fitted the Freundlich isotherm and pseudo-second-order kinetics models. The proposed SPE using PVA/GT-MIN coupled with high performance liquid chromatography-diode array detection presented good linearity from 50 µg/L-5 mg/L (R2 = 0.9999) and yielded a limit of detection of 21 µg/L. The PVA/GT-MIN was applied to extract bottled water for BPA analysis and recoveries were 93.1-97.7 % (RSDs ≤ 3.6 %). This study presents a novel, easily prepared PVA/GT-MIN adsorbent for the extraction of BPA in water.

Sustainable carbonaceous nanomaterial supported palladium as an efficient ligand-free heterogeneouscatalyst for Suzuki-Miyaura coupling.

A novel ligand-free heterogeneous catalyst was synthesized via pyrolysis of Samanea saman pods to produce carbon nanospheres (SS-CNSs), which served as a carbon support for immobilizing palladium nanoparticles through an in situ reduction technique (Pd/SS-CNS). The SS-CNSs effectively integrated 3% of Pd on their surfaces with no additional activation procedures needed. The nanomaterials obtained underwent thorough characterization employing various techniques such as FT-IR, XRD, FE-SEM, TEM, EDS, ICP-AES, and BET. Subsequently, the efficiency of this Pd/SS-CNS catalyst was assessed for the synthesis of biaryl derivatives via Suzuki coupling, wherein different boronic acids were coupled with various aryl halides using an environmentally benign solvent mixture of EtOH/H2O and employing only 0.1 mol% of Pd/SS-CNS. The catalytic system was conveniently recovered through centrifugation and demonstrated reusability without any noticeable decline in catalytic activity. This approach offers economic viability, ecological compatibility, scalability, and has the potential to serve as an alternative to homogeneous catalysis.

A novel double metal-dithizone functionalized polyurethane electrospun nanofiber and film for colorimetric determination of hexavalent chromium.

This work proposes a highly specific method of Cr6+ determination based on the double reactions of two metals, Co2+ with dithizone to form a (DTZ)-Co2+ complex, and the replacement of Co2+ in the formed complex with Cr6+. The fast degradation of DTZ in solution in wet analysis was overcome by preparing dithizone functionalized polyurethane nanofibers that were electrospun into a membrane (DTZ/PU-NF) and a microwell plate film (DTZ/PU-MPF). For comparison, the performance of diphenylcarbazide (DPC), a currently used complexing agent for Cr6+, was also investigated. Colour changes were detected as red-green-blue values. The DTZ/PU-NF was smooth, with an average diameter of 384.09 nm and no bead appeared. A dense network structure was formed. The best formulation of DTZ, PU and Co2+ was also applied as a microwell plate film. In the presence of Cr6+, the colour of DTZ-Co2+ changed from red to magenta. Among the three studied methods, the colorimetric DTZ-Co2+/PU-NF presented the best results. Its linearity range was 0.001-1.0 mg L-1, with a regression equation of Cr6+ = -0.189 + (0.0056 × red) + (0.0086 × green) - (0.0129 × blue), R 2 of 0.990. The limit of detection was 0.001 mg L-1 and the precision was 1.7%. The applicability of DTZ/PU-NF was validated for Cr6+ in vegetable oils with recoveries of 89.5-116.8%. The sensitivity of DTZ/PU-NF was ten times higher than that of DTZ/PU-MPF. The methods based on DTZ-Co2+/PU-NF and DTZ-Co2+/PU-MPF proved to be highly selective, rapid, user-friendly, simple and reliable.

Broadband single-molecule fluorescence enhancement based on self-assembled Ag@Au dimer plasmonic nanoantennas.

Dimer optical antennas (OAs) enable great fluorescence enhancement and excitation volume reduction and hence potentially can be a very useful tool for single-molecule detection. The realization of broadband fluorescence enhancement with a dimer OA remains an essential step for its usage in multi-color single-molecule fluorescence (SMF) detection. Although silver dimer OAs have been shown to be able to yield broadband fluorescence enhancement over the visible spectrum, they are amenable to oxidization, hard to functionalize, and could cause cytotoxicity. To overcome these limitations, in this work, we took advantage of nano-sized silver due to its optical properties and gold due to its chemical properties and developed an ameliorated Ag@Au dimer OA in terms of its overall performance. The Ag@Au nanoparticle in the dimer OA contains a 70 nm silver core and an ultra-thin (∼1-5 nm) gold shell which play a key role in its optical responses. Furthermore, we employed three typical dyes, i.e., FAM, TAMRA and Cy5, representing the blue, yellow and red ranges, respectively, and characterized their single-molecule fluorescence enhancements in the presence of Au or Ag@Au OAs. Our results indicate that, in contrast to its Au counterpart, the Ag@Au dimer OA prepared here can greatly improve its optical response in the blue range and eventually achieve broadband fluorescence enhancement throughout almost the whole visible spectral range. Meanwhile, it also maintains good chemical stability and accessibility to functionalization. Such Ag@Au dimer OAs are thus expected to have many important applications in the future, including single-molecule sequencing and multi-color biosensing.

In situ polar organic chemical integrative sampling (POCIS) of steroidal estrogens in sewage treatment works discharge and river water.

A passive sampler (the polar organic chemical integrative sampler; POCIS) was assessed for its ability to sample natural estrogens (17ß-estradiol, E2; estrone, E1 and estriol, E3) and the synthetic estrogen (17α-ethynylestradiol, EE2) in the outlet of a sewage treatment works over several weeks. The performance of the POCIS was investigated and optimised in the laboratory before field deployment with high recoveries (66-99%) were achieved for all estrogens. Moreover, it was shown that POCIS does not exhibit any preferential selectivity towards any of the target compounds. The sampling rates of E1, E2 and E3 were 0.018 ± 0.009, 0.025 ± 0.014 and 0.033 ± 0.019 L d(-1), respectively. Following field deployments of 28 days in the discharge of a sewage works, POCIS was shown to enhance the sensitivity of estrogen detection, especially for E3, and provide time-weighted average (TWA) concentrations of E1, E2 and E3, ranging from undetectable to 12 ng L(-1) upstream of the outflow of a sewage treatment works, 13 to 91 ng L(-1) at the outflow and 8 to 39 ng L(-1) downstream of the outflow. This revealed that E1, E2 and E3 are not completely removed during sewage treatment, with concentrations most likely being maintained by contributions from conjugated estrogen analogues. Grab water samples showed considerable variation in the concentrations of estrogens over a longer period (6 months). The results confirm that POCIS is an effective and non-discriminatory method for the detection of low concentrations of estrogens in the aquatic environment.

Highly sensitive colorimetric sensing of copper(ii) ions based on "CLICK-17" DNAzyme-catalyzed azide modified gold nanoparticles and alkyne capped dsDNA cycloaddition.

A click chemistry assay based on a newly discovered DNAzyme, CLICK-17, with azide modified gold nanoparticles (azide-AuNPs) and alkyne capped dsDNA (alkyne-linker DNA) was employed for novel and selective detection of Cu2+ visually. The strategy involved using CLICK-17 to mediate a catalytic reaction for triazole formation between azide-AuNPs and alkyne-linker DNA under the help of Cu2+ (without sodium ascorbate) or Cu+, which eventually led to the aggregation of AuNPs. The obvious color change from ruby red to bluish purple was then observed by the naked eye and the absorbance peak shifted from 525 to 570 nm. Interestingly, CLICK-17 and Cu+-catalyzed click reaction had the best performance compared to either Cu+ alone or CLICK-17 and Cu2+-mediated reaction in terms of the reaction time and sensitivity. This system has been demonstrated to allow quantitative measurement of Cu2+ with a detection limit as low as 26.8 nM and also has high specificity that can distinguish Cu2+ from other metal ions. Further, the method was tested with a real mineral water sample for Cu2+ concentration determination. Satisfactory recoveries of 90.8% and 99.8% were achieved.

Sensitive colorimetric detection of ascorbic acid based on seed mediated growth of sodium alginate reduced/stabilized gold nanoparticles.

A sensitive detection strategy for ascorbic acid (AA), using sodium alginate reduced/stabilized gold nanoparticles (SA-AuNPs) as the optical probe, is reported. The SA-AuNPs were prepared by mixing gold salt and SA under stirring for 2 h at room temperature, without any further steps. The mixture was aged at 4 °C overnight, after which a faint-purple colloidal solution of SA-AuNPs was obtained. Characterization shows that the synthesis is incapable of reducing all Au3+ to Au°, but rather to mixture of Au°/Au+. The addition of AA to the SA-AuNPs probe reduced completely all Au+ to new AuNPs which were deposited on the pre-formed SA-AuNPs seed, leading to size increment and absorption spectra enhancement. The assay exhibited a good linearity between 12.5 and 150.0 µM AA and low limit of quantification of 11.2 µM. It was further used for AA quantitation in vitamin C injection and fruit juice with satisfactory accuracy and precision.

Quantifying the force in flow-cell based single-molecule stretching experiments.

The flow-cell based single-molecule manipulation technique has found many applications in the study of DNA mechanics and protein-DNA interactions. However, the force in these experiments has not been fully characterized and is usually limited to a moderate force regime (<25 pN). In this work, using the "tethered-bead" assay, the hydrodynamic drag of DNA has been quantitatively evaluated based on a "bead-spring chain" model. The force derived from the Brownian motion of the bead thus contains both contributions from this equivalent hydrodynamic drag of DNA and the pulling force from the tethered bead. Next, using flow-cell based DNA pulling experiments, the linear relationship between the flow rate and total hydrodynamic force on the bead-DNA system has been demonstrated to be valid over a wide force range (0-110 pN). Consequently, the force can be directly converted from the flow rate by a linear factor that can be calibrated either by the bead's Brownian motion at low flow rates or using DNA overstretching transition. Furthermore, the hydrodynamic force and torque due to the shear flow on the bead as well as the equivalent stretching force on DNA are calculated based on theoretical models with the hydrodynamic drag on DNA also considered. The calculated force-extension curves show a good agreement with the measured ones. These results offer important insights into the force in flow-cell based single-molecule stretching experiments and provide a foundation for establishing flow-cells as a simple, low-cost, yet flexible and precise tool for single-molecule force measurements over a wide force range.

Characterization of pharmaco-EEG fingerprint and sleep-wake profiles of Lavandula angustifolia Mill. essential oil inhalation and diazepam administration in rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Lavandula angustifolia Mill. Essential oil (Lavender EO) has a long history of medicinal use and is particularly claimed to possess anxiolytic and sedative properties. Lavender EO aromatherapy has been used to reduce distress and improve insomnia naturally. Increasing evidence appeared to show similarities between the effects of lavender EO and the anxiolytic drugs, benzodiazepines. However, its effects on sleep-wake and electrical brain patterns in comparison to that of the standard anxiolytic, diazepam, remained to be explored. AIM OF THE STUDY: The aim of this work was to investigate electroencephalography (EEG) profiles and sleep-pattern elicited by lavender EO inhalation compared to that of diazepam, a standard anxiolytic drug in in vivo rat model. MATERIALS AND METHODS: Adult male Wistar rats were anesthetized for electrode implantation on the frontal and parietal skulls. EEG signals were recorded for 180 min following intraperitoneal injection of diazepam (10 mg/kg) or during continuous inhalation of lavender EO (200 µL) or distilled water (control). Fast Fourier transform was used for the analyses of EEG power spectra and sleep-wake parameters. RESULTS: During a 30-60 min period, diazepam and lavender EO significantly increased frontal powers of 0.78-45.31 and 7.03-18.36 Hz, respectively. Both treatments also increased parietal powers with lower magnitudes of significant change. Significant increases in some frequency ranges remained until a 60-90 min period. Sleep-wake analyses also revealed that diazepam significantly reduced time spent in wake, increased time spent in non-rapid eye movement (NREM), increased episode duration of NREM, decreased numbers of wake episode and decreased rapid eye movement (REM) sleep latency. On the other hand, lavender EO only significantly decreased wake episodes and latency to REM sleep. Lavender EO inhalation reduced numbers of wake episode but maintain normal time spent in wake, NREM and REM sleeps. CONCLUSIONS: These findings might suggest beneficial and distinct anxiolytic-like effects of lavender EO for sleep enhancing purposes.

Synthesis of gold nanoparticles/polyaniline boronic acid/sodium alginate aqueous nanocomposite based on chemical oxidative polymerization for biological applications.

Gold nanoparticles/polyaniline boronic acid/sodium alginate aqueous nanocomposite ((PABA-SAL)@AuNPs) was fabricated. Aniline boronic acid (ABA) served as reductant of gold salt, all within the SAL solution. While ABA reduced gold salt to its nanoparticles, the ABA monomer was also oxidized to its conducting polymeric form (PABA). The presence of PABA in the reaction mixture exerted solubility and stability challenge, thus SAL was used as stabilizer and solubilizer for PABA. The numerous cis-diol groups of SAL could bind to boronic acid groups of PABA to furnish PABA-SAL repeating polymer structure for AuNPs anchoring. Sparkling ruby red (PABA-SAL)@AuNPs have absorption peaks at 529 and 718 nm. Average particle sizes of nanocomposite were within 15-20 nm, with hydrodynamic diameter of 48.6 ± 0.9 nm, zeta potential of -32.5 ± 1.6 mV and conductivity value of 2015.3 ± 3.2 µS/cm. (PABA-SAL)@AuNPs possessed antibacterial activities against seafood associated bacterial isolates, with MIC and MBC ranging from 4 to 8 µg/mL. The moderate antioxidant capacity of (PABA-SAL)@AuNPs was observed, without any deleterious damages on human red blood cells. It also has good biocompatibility on Caco-2 and RAW 264.7, with cell viability not less than 70%. These results confirm the high prospect of (PABA-SAL)@AuNPs for possible biomedical applications.