PbS Concentration Research Articles

A Comparative Study of the Linear/Nonlinear Optical, and Dielectric Properties of PVA/CMC/(1−x)ZnWO4−xPbS Blended Polymers for Optoelectronic Applications

An analysis was conducted on the optical, structural, and dielectric characteristics of PVA/CMC/(1−x)ZnWO4/xPbS blends. The structures of the filler samples, undoped, and doped blends were examined using X-ray diffraction. The crystallite sizes of the various phases in the filler samples are affected by the amount of PbS in the nanocomposite. The morphologies of different blends were explored using scanning electron microscopy. The doped blend exhibited superior absorption of Ultraviolet A (UVA) and Ultraviolet B (UVB) types in addition to the visible spectrum. The optical band gaps were minimized to (5.37, 5.56, 4.11) and (4.76, 3.14, 2.92) eV for direct and indirect optical transitions, respectively, when the PVP/CMC doped with nanocomposite had 10% PbS. The highest refractive index, optical dielectric constant,and nonlinear optical parameter values were achieved when the blend was loaded with ZnWO4 only while the highest optical conductivity was obtained as the blend contained 15% PbS. The highest fluorescence intensity was observed when the fillers did not contain PbS, and it decreased as the concentration of PbS in the filler increased.

A high-entropy electrode material for electrobiochemical and eletrophysiological signals detection

Electrobiochemical and eletrophysiological signals indicate human physiology, health, and activity performance. It is still a big challenge to detect these biosignals due to the lack of sensing material. Here, we report a high-entropy material for electrobiochemical and eletrophysiological signals sensing. The high-entropy material consists of the conventional transition metallic elements of Fe, Co, Ni, Cu, and Zn. This high-entropy biosignal sensing material is able to detect the concentration of the biomarker of glucose and electrophysiological signals of Electromyography (EMG), Electroencephalography (EEG), Electrocardiography (ECG). The limitation of the glucose detection is 3.3 μM with the sensitivity of 2861 μA mM−1 cm−2. The HEA electrode also presents good linearship to the glucose concentration in PBS. The cell assay and skin assessment results also demonstrate the excellent biocompatibility of this HEA electrode, indicating good feasibility to the real biosamples. The contact impedance of this HEA electrode is lower than the conventional dry electrode, which leads to the good capability in electrophysiological signals detection. This report not only extends the application of high-entropy material in the field of biomedical engineering but also provides a new pathway for electrobiochemical and eletrophysiological signals detection.

Controllable synthesize of ZnS/PbS nanostructure and their structural and morphological properties

ZnS is an appealing material with wide potential applications in optoelectronics, sensors, and photocatalysis due to its fascinating properties, low cost, and eco-friendly. In this paper, we report the synthesis of ZnS nanowires and nanorods via a simple thermal-evaporation method using different concentrations of PbS as a dopant. The prepared nanostrutures were investigated in detalis using a scanning electron microscopy (SEM), X-ray diffraction (XRD), and high resolution transmission electron microscopy (HRTEM). The results show that the fabricated ZnS nanowire/nanorod has a wurtzite (hcp) structure. In addition, based on the experimental results, the growth mechanism of the prepared nanostructures is reported. X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray (EDX) mapping analyses confirmed that the ZnS nanorods were stoichiometric without impurities or defects, whereas PbS quantum dots were formed inside the high-quality nanowires. The formation mechanism of ZnS nanowires is discussed based on the vapor–liquid–solid (VLS) growth model. Results demonstrated that thermal evaporation is a simple and effective techniques for producing high-quality heterostructured ZnS nanowires with potential applications in different fields.

Influence of polymer matrices on the structural, morphological, thermal, and optical properties of PbS nanoparticles embedded in electrospun nanofibers

The development of electrospun nanomaterials with tunable optical and structural properties has significant implications for various applications. Herein, we develop a controllable and efficient strategy for in situ-grown Lead sulfide (PbS) nanoparticles (NPs) in the electrospun PVA-PVP blend nanofibers. The fibrous mats have been synthesized for different concentrations of PbS NPs grown in the PVA-PVP blend along with its parent polymers, PVA and PVP. The study uniquely enables the in-situ growth of PbS NPs within these matrices, resulting in nanofibers with tunable optical and structural properties. The synthesized PbS/Polymer nanofibers exhibit significant variation in bandgap values, ranging from 2.7 to 1.16 eV for PbS concentrations between 0.05 M and 0.2 M across all polymer matrices. Furthermore, our findings suggest that the interaction between the PbS NPs and polymer matrix does not solely result in simple additive effects. The observed results have been comprehensively analyzed, considering the intricate effects of quantum confinement.

Immunogenic and toxic effects of graphene oxide nanoparticles in mouse skeletal muscles and human red blood cells

To investigate immunogenic and toxic effects of graphene oxide (GO) nanoparticles in mouse skeletal muscles and in human blood in vitro. GO nanoparticles prepared using a probe sonicator were supended in deionized H2O or PBS, and particle size and surface charge of the nanoparticles were measured with dynamic light scattering (DLS). Different concentrations (0.5, 1.0 and 2.0 mg/mL) of GO suspension or PBS were injected at multiple sites in the gastrocnemius muscle (GN) of C57BL/6 mice, and inflammatory response and immune cell infiltrations were detected with HE and immunofluorescence staining. We also examined the effects of GO nanoparticles on human red blood cell (RBC) morphology, hemolysis and blood coagulation using scanning electron microscope (SEM), spectrophotometry, and thromboelastography (TEG). GO nanoparticles suspended in PBS exhibited better colloidal dispersity, stability and surface charge effects than those in deionized H2O. In mouse GNs, injection of GO suspensions dose- and time-dependently resulted in sustained muscular inflammation and myofiber degeneration at the injection sites, which lasted till 8 weeks after the injection; immunofluorescence staining revealed obvious infiltration of monocytes, macrophages, dendritic cells and CD4+ T cells around the injection sites in mouse GNs. In human RBCs, incubation with GO suspensions at 0.2, 2.0 and 20 mg/mL, but not at 0.002 or 0.02 mg/mL, caused significant alterations of cell morphology and hemolysis. TEG analysis showed significant abnormalities of blood coagulation parameters following treatment with high concentrations of GO. GO nanoparticles can induce sustained inflammatory and immunological responses in mouse GNs and cause RBC hemolysis and blood coagulation impairment, suggesting its muscular toxicity and hematotoxicity at high concentrations.

Facile synthesize and enhanced thermoelectric performance of PbS with Cl doping and PbSe alloying

Besides inferior conversion efficiency, the widespread application of thermoelectric materials currently faces the challenges of the rare and high cost of constituent elements, complex and time-consuming synthesis. Therefore, it is urgent to develop facile synthesized methods and high-performance thermoelectric materials consisting of elements with earth-abundance and low cost. Meeting above partial requirement, lead sulfide (PbS) recently was identified as a potential thermoelectric material to substitute current commercial PbTe. In this paper, a one-step high-pressure method was employed to facile and fast synthesis of PbS. Trace Cl doping tunes the carrier concentration of PbS effectively, which optimizes the electrical transport properties. Further PbSe alloying sharply reduces the thermal conductivity of PbS. Therefore, an enhanced zT∼1.0 @ 700 K was obtained for PbS doped with 0.3 at% Cl and alloyed with 25 at% PbSe, which is comparable to the commercially applied PbTe. These results indicate that high-pressure combing with Cl-doping and PbSe-alloying provide a facile method and strategy to fabricate high-performance PbS-based thermoelectric materials.

Optimization of the Centrifugal Spinning Parameters to Prepare Poly(butylene succinate) Nanofibers Mats for Aerosol Filter Applications.

Air pollution is becoming a serious issue because it negatively impacts the quality of life. One of the first most useful self-defense approaches against air pollution are face masks. Typically made of non-renewable petroleum-based polymers, these masks are harmful to the environment, and they are mostly disposable. Poly(butylene succinate) (PBS) is regarded as one of the most promising materials because of its exceptional processability and regulated biodegradability in a range of applications. In this regard, nanofiber-based face masks are becoming more and more popular because of their small pores, light weight, and excellent filtration capabilities. Centrifugal spinning (CS) provides an alternative method for producing nanofibers from various materials at high speeds and low costs. This current study aimed to investigate the effect of processing parameters on the resultant PBS fiber morphology. Following that, the usability of PBS nonwoven as a filter media was investigated. The effects of solution concentration, rotating speed, and needle size have been examined using a three-factorial Box-Behnken experimental design. The results revealed that PBS concentration had a substantial influence on fiber diameter, with a minimum fiber diameter of 172 nm attained under optimum production conditions compared to the anticipated values of 166 nm. It has been demonstrated that the desired function and the Box-Behnken design are useful instruments for predicting the process parameters involved in the production of PBS nanofibers. PBS filters can achieve an excellent efficiency of more than 98% with a pressure drop of 238 Pa at a flow rate of 85 L/min. The disposable PBS filter media was able to return to nature after use via hydrolysis processes. The speed and cost-effectiveness of the CS process, as well as the environmentally benign characteristics of the PBS polymer, may all contribute considerably to the development of new-age filters.

γ-Ray-Induced Photocatalytic Activity of Bi-Doped PbS toward Organic Dye Removal under Sunlight.

Photocatalysts based on semiconducting chalcogenides due to their adaptable physio-chemical characteristics are attracting attention. In this work, Bi-doped PbS (henceforth PbS:Bi) was prepared using a straightforward chemical precipitation approach, and the influence of γ-irradiation on PbS's photocatalytic ability was investigated. Synthesized samples were confirmed structurally and chemically. Pb(1-x)BixS (x = 0, 0.005, 0.01, 0.02) samples that were exposed to gamma rays showed fine-tuning of the optical bandgap for better photocatalytic action beneath visible light. The photocatalytic degradation rate of the irradiated Pb0.995Bi0.005S sample was found to be 1.16 times above that of pure PbS. This is due to the occupancy of Bi3+ ions at surface lattice sites as a result of their lower concentration in PbS, which effectively increases interface electron transport and the annealing impact of gamma irradiation. Scavenger tests show that holes are active species responsible for deterioration of the methylene blue. The irradiated PbS:Bi demonstrated high stability after being used repeatedly for photocatalytic degradation.

Multifilament Collagen Fiber Bundles with Tendon-like Structure and Mechanical Performance.

Collagen multifilament bundles comprised of thousands of monofilaments are prepared by multipin contact drawing of an entangled polymer solution consisting of collagen and poly(ethylene oxide) (PEO). The multifilament bundles are hydrated in graded concentrations of PEO and phosphate buffered saline (PBS) to promote assembly of collagen fibrils within each monofilament while preserving the structure of the multifilament bundle. Multiscale structural characterization reveals that the hydrated multifilament bundle contains properly folded collagen molecules packed in collagen fibrils containing microfibrils, staggered by exactly one-sixth of the microfibril D-band spacing to produce a periodicity of 11nm. Sequence analysis predicts that in this structure, phenylalanine residues are close enough within and between microfibrils to become ultraviolet C (UVC) crosslinked. In agreement with this analysis, the ultimate tensile strength (UTS) and Young's modulus of the hydrated collagen multifilament bundles crosslinked by UVC radiation increase nonlinearly with total UVC energy to reach values in the range of native tendons without damage to the collagen molecules. This fabrication method recapitulates the structure of a tendon across multiple length scales and offers tunability in tensile properties using only collagen molecules and no other chemical additives in addition to PEO, which is almost entirely removed during the hydration process.

Label free impedance based acetylcholinesterase enzymatic biosensors for the detection of acetylcholine

Realtime monitoring of neurotransmitters is of great interest for understanding their fundamental role in a wide range of biological processes in the central and peripheral nervous system, as well as their role, in several degenerative brain diseases. The measurement of acetylcholine in the brain is particularly challenging due to the complex environment of the brain and the low concentration and short lifetime of acetylcholine. In this paper, we demonstrated a novel, label-free biosensor for the detection of Ach using a single enzyme, acetylcholinesterase (ACHE), and electrochemical impedance spectroscopy (EIS). Acetylcholinesterase was covalently immobilized onto the surface of gold microelectrodes through an amine-reactive crosslinker dithiobis(succinimidyl propionate) (DSP). Passivation of the gold electrode with SuperBlock eliminated or reduced any non-specific response to other major interfering neurotransmitter molecules such as dopamine (DA), norepinephrine (NE) and epinephrine (EH). The sensors were able to detect acetylcholine over a wide concentration range (5.5–550 μM) in sample volumes as small as 300 μL by applying a 10 mV AC voltage at a frequency of 500 Hz. The sensors showed a linear relationship between Ach concentration and ΔZmod(R2 = 0.99) in PBS. The sensor responded to acetylcholine not only when evaluated in a simple buffer (PBS buffer) but in several more complex environments such as rat brain slurry and rat whole blood. The sensor remained responsive to acetylcholine after being implanted ex vivo in rat brain tissue. These results bode well for the future application of these novel sensors for real time in vivo monitoring of acetylcholine.

In-situ synthesis of PbS nanocomposites films in PEOX-PVA: Interaction effect of parent polymer matrix on structural and optical properties

This paper reports the in-situ synthesis of PbS nanoparticle films grown in the PEOX-PVA polymer matrix. The films have been prepared for various concentrations of PbS nanoparticles developed in blend polymer PEOX-PVA along with its parent polymers PEOX and PVA. The effect of polymer matrix on its structural properties has been studied using Rietveld analysis of x-ray diffraction data to determine the following parameters, i.e., crystal structure, space group, lattice parameter, and crystallite size. The chemical bonding and interaction effect of the parent polymer matrix with PbS nanoparticles have been analysed using FTIR and thermal gravimetry. Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) have been used to observe the overall morphology of the nanocomposites. The variation in the bandgap of PbS nanocomposite films has been determined from 3.6 to 1.25 eV with varying concentrations of PbS (0.01 M–0.1 M) in all three polymer matrices. The refractive index of PbS nanocomposites films deduced at λ = 650 nm to be 1.4333 to 1.5612, which is much lower than the bulk value of 4.2. It is inferred from the present study that the interaction of polymer matrices with the PbS does not lead to mere addition. Detailed results are analysed considering the quantum confinement effect.

Structural, morphological, optical, and thermal properties of electrospun PbS/PVP-PEO nanofibers

This study describes the preparation and characterization of PVP-PEO nanofibers filled with PbS nanoparticles. The effect of polymer concentrations, surface morphology, and diameter distribution studies of the nanofibers was evaluated by Scanning Electron Microscopy (SEM). The SEM images revealed that smooth and homogeneous nanofibers could be achieved at 12% PVP-PEO (50:50 wt%) concentration. The XRD and TEM analysis confirmed the formation of PbS nanoparticles in the PVP-PEO blend matrix, which also revealed the high crystalline behaviour of the PbS nanoparticles. The XRD data showed that the intensity and average crystallite size increase with PbS concentration. The FTIR and TGA studies revealed the interaction between PbS nanoparticles and the PVP-PEO blend matrix. UV–Vis diffuse reflectance studies have shown that the reflectance onset shifted toward a blue shift than bulk PbS. The optical bandgap determined using the Kubelka-Munk function lies 1.08–1.56 eV range by varying PbS concentration.

Electrospun Membranes of Poly(butylene succinate) and Poly(butylene/2‐butyl,2‐ethyl‐propylene succinate)

AbstractPoly(butylene succinate) (PBS) and poly(butylene/2‐butyl,2‐ethyl‐propylene succinate) (PBSBEPS) membranes are prepared by electrospinning technique. In recent years, interest in biodegradable aliphatic polyesters, including PBS and its copolymers, is increasing as they have potential applications in various sectors such as mulching films, food packaging, tissue engineering, and drug delivery. In this work, the synthesized polymers are dissolved in different solvents, namely acetone, chloroform (CHCl3), methanol, dichloromethane (DCM), and dimethylformamide in order to obtain the best solvent system. These solutions are then electrospun at room temperature to produce micron‐sized fibers. The variables examined in determining the optimal solution and electrospinning conditions are the solvent system used, the concentration of PBS and PBS‐based random copolymer, applied voltage, flow rate, humidity, and the distance between the needle tip and the collector, all of which have a meaningful effect on the fiber morphology. Among the various solvents used, the DCM and the less toxic CHCl3 result in fewer bead defects among fibers. Besides, an increase in PBS and PBS‐based random copolymer concentration determines the reduction of bead defects, which from 12 to 14 wt% results in bead‐free uniform fibers, when suitable processing parameters are set. Promising results, which can pave the way for the production of membranes loaded with appropriate anticancer molecules for targeted biomedical applications, are obtained.

Improved linear and nonlinear optical properties of PbS thin films synthesized by spray pyrolysis technique for optoelectronics: An effect of Gd3+ doping concentrations

In the present article, the pure PbS and different concentrations of Gd doped PbS (Gd:PbS) films were developed using the spray pyrolysis route by growing thin films on the glass substrate. The estimated crystallite sizes were found from 15.5 to 20.8 nm for as-deposited films. The spherical shape morphology of grains was observed by FESEM. The obtained average grain sizes varied from 52.8 to 108.2 nm were obtained from the grain size distributions for 0.0, 0.5, 1.5, and 2.5 wt % Gd: PbS films, respectively. Extinction coefficients of as-deposited films were measured from 0.04 to 0.12 in the range of wavelength 200–2500 nm. Refractive indices of films were obtained from 5.4 to 1.22 in range of 200–2500 nm wavelength. The band gaps of 2.75, 2.64, 2.45, and 3.10 eV for 0.0, 0.5, 1.0 and 2.5 wt % Gd thin films were estimated using Tauc's relation respectively. The values of the dielectric constant, dielectric loss, and optical conductivity were recorded in the range of 1.32–29.6, 0.30–0.61, and 2.34 × 1014–3.08 × 1013 between 200 and 2500 nm wavelengths for as-deposited thin films respectively. The optimum values of linear susceptibility, non-linear susceptibility and refractive index were recorded in the range of 1.23–2.93, 5.21 × 10−10 - 120 × 10−10, 3.54 × 10−9 – 74.2 × 10−9 (esu) between 1.46 and 0.52 eV respectively for as-deposited thin films. The Gd: PbS thin films improve the physical properties and therefore, it becomes suitable candidature for the applications in optoelectronic devices.

Cytotoxic Effect of Cypermethrin and Neem Extract on Human Lymphocytes

There is a need to increase our agricultural production of food grains and other crops to feed a continuously increasing population. To achieve this food security, use of insecticides/pesticides has become necessary. Cypermethrin is a pyrethroid insecticide used for control of pests of cereals, fruits, vegetables and cotton etc. but it has several toxic effects on human beings. Apart from being neurotoxic, it has harmful effects on lymphocytes also. Neem is also a potent insecticide of herbal and indigenous origin. In this investigation the cytotoxicity of cypermethrin (dissolved in DMSO) and aqueous extract of neem leaves to human lymphocytes was studied by MTT assay. It was found that after an exposure of two hours to LC50 concentration of cypermethrin viability of lymphocytes fell to 87.83%; however at lower concentration the viability fell further because of the increase in the DMSO concentration, proving the toxicity of DMSO. Treatment of lymphocytes with 45% of neem extract increased the viability by 196% but at lower concentrations lesser increase was noted due to the increase in concentration of PBS. Thus apart from being a safe insecticide neem extract can be used to promote viability and proliferation of cells of animal origin also.

Fabrication of an Immobilized Polyelectrolite Complex (PEC) Membrane from Pectin-Chitosan and Chromoionophore ETH 5294 for pH-Based Fish Freshness Monitoring

Considering the significance of its demand around the world, the accurate determination of fish freshness with a simple and rapid procedure has become an interesting issue for the fishing industry. Hence, we aimed to fabricate a new optical pH sensor based on a polyelectrolyte (PEC) membrane of pectin–chitosan and the active material chromoionophore ETH 5294. A trial-and-error investigation of the polymer compositions revealed that the optimum ratio of pectin to chitosan was 3:7. With an optimum wavelength region (λ) at 610 nm, the constructed sensor was capable of stable responses after 5 min exposure to phosphate-buffered solution. Furthermore, the obtained sensor achieved optimum sensitivity when the PBS concentration was 0.1 M, while the relative standard deviation values ranged from 2.07 to 2.34%, suggesting good reproducibility. Further investigation revealed that the sensor experienced decreased absorbance of 16.67–18.68% after 25 days of storage. Employing the optimum conditions stated previously, the sensor was tested to monitor fish freshness in samples that were stored at 4 °C and ambient temperature. The results suggested that the newly fabricated optical sensor could measure pH changes on fish skin after 25 h storage at room temperature (pH 6.37, 8.91 and 11.02, respectively) and 4 °C (pH 6.8, 7.31 and 7.92, respectively).

High-Performance Supercapacitor Electrode Material Based on the Two-Dimensional/Three-Dimensional Architecture of MoS2–PbS Hybrid Material

The synthesis of the stable hybrid material for electrodes to exhibit stupendous supercapacitor functioning is an actual challenge. Here, we present a two-step synthesis by a chemical route method followed by a hydrothermal technique to produce two-dimensional (2D)/three-dimensional (3D) hybrid material, wherein MoS2 nanosheets were integrated with the 3D cube-like network of PbS. The multiple MoS2/PbS hybrid structures are synthesized by varying the concentration of PbS. The characterization tools, such as X-ray diffraction, Fourier transform infrared, and ultraviolet–visible spectroscopy, approve the co-existence of MoS2 and PbS, while field emission scanning electron microscopy and transmission electron microscopy conclusions approve the distinctive microstructures. Brunauer–Emmett–Teller is also performed to compare the surface areas of pristine MoS2 nanosheets and MoS2/PbS-based hybrid material. Remarkably, the optimized concentration of the metal sulfide (PbS)-loaded MoS2/PbS (MP100) hybrid structure yielded the highest double-layer capacitance value of 205.50 F/g in a 1 M Na2SO4 electrolyte (scan rate of 10 mV/s), whereas pure MoS2 nanosheets showed 40.04 F/g. The inclusion of metal sulfide heightened the supercapacitive parameters of pure MoS2 nanosheets. The significant supercapacitive application of the hybrid material can be accredited to the synergistic effect amid the 3D network of interconnected MoS2 nanosheets surrounded by metal sulfide (PbS) providing an enhanced surface area and the lowest charge transfer resistance.

Design of hybrid PLA/PBS/POM composite based on In-Situ formation of interpenetrating fiber networks

Hybrid polymer–polymer nanocomposite of polylactide/poly(1,4-butylene succinate)/ polyoxymethylene (PLA/PBS/POM) system with interpenetrating fiber network was manufactured. Hybridization was by combining tough, in situ generated PBS nanofibers with rigid, ready-made electrospun POM nanofibers. The concentration of PBS and POM components was 10 wt% to establish continuous fiber network. Nanoporous surface of POM nanofibers with high specific surface area enabled strong interfacial interaction with PLA matrix. A positive effect of hybridization on mechanical properties was achieved for composite with interpenetrating network of POM and PBS fibers. Compared to PLA/PBS/POM blend, the PLA/PBS/POM composite was characterized by increase in: elastic modulus, yield stress, tensile impact strength and strain at break. Presence of POM fibers caused increase: in crystallinity and in crystallization temperature of PBS due to shear-induced crystallization. Presence of PBS and POM nanofibers caused a change of plastic deformation of PLA matrix from heterogeneous intensive crazing to homogeneous.

Neutral Nonenzymatic Glucose Biosensors Based on Electrochemically Deposited Pt/Au Nanoalloy Electrodes

BackgroundType I diabetes occurs when the pancreas can only make limited or minimal insulin. Patients with type 1 diabetes need effective approaches to manage diabetes and maintain their blood-glucose concentration. Recently, continuous glucose monitoring (CGM) has been used to help control blood-glucose levels in patients with type 1 diabetes. Patients with type 2 diabetes may also benefit from CGM on multiple insulin injections, basal insulin, or sulfonylureas. Enzyme-free glucose detection in a neutral environment is the recent development trend of CGM.Materials and MethodsPt/Au alloy electrodes for enzyme-free glucose detection in a neutral environment were formed by electrochemically depositing Pt/Au alloy on a thin polycarbonate (PC) membrane surface with a uniformly distributed micro-hemisphere array. The PC membranes were fabricated using semiconductor microelectromechanical manufacturing processes, precision micro-molding, and hot embossing. Amperometry was used to measure the glucose concentration in PBS (pH 7.4) and artificial human serum.ResultsThe Pt/Au nanoalloy electrode had excellent specificity for glucose detection, according to the experimental results. The device had a sensitivity of 2.82 μA mM−1 cm−2, a linear range of 1.39–13.9 mM, and a detection limit of 0.482 mM. Even though the complex interfering species in human blood can degrade the sensing signal, further experiments conducted in artificial serum confirmed the feasibility of the proposed Pt/Au nanoalloy electrode in clinical applications.ConclusionThe proposed Pt/Au nanoalloy electrode can catalyze glucose reactions in neutral solutions with enhancing sensing performance by the synergistic effect of bimetallic materials and increasing detection surface area. This novel glucose biosensor has advantages, such as technology foresight, good detection performance, and high mass production feasibility. Thus, the proposed neutral nonenzymatic glucose sensor can be further used in CGMs.

Optimization of the extraction conditions and dermal toxicity of oil body fused with acidic fibroblast growth factor (OLAF)

Introduction Oil body (OB), a subcellular organelle that stores oil in plant seeds, is considered a new transdermal drug delivery system. With the increasing understanding of the OB and its main protein (oleosin), numerous studies have been conducted on OB as “carrier” for the expression of exogenous proteins. In our previous study, oil body fused with aFGF (OLAF) was obtained using a plant oil body expression system that had been preliminarily proven to be effective in accelerating the healing of skin wounds. However, no dermal toxicological information on OLAF is available. Objective To ensure the dermal safety of OLAF, a series of tests (the acute dermal toxicity test, 21-day repeat dermal toxicity test, dermal irritation test and skin sensitisation test) were conducted after optimising the extraction protocol of OLAF. Materials and methods To improve the extraction rate of OLAF, response surface methodology (RSM) was first employed to optimise the extraction conditions. Then, Wistar rats were exposed to OLAF (400 mg·kg−1 body weight) in two different ways (6 hours/time for 24 hours and 1 time/day for 21 days) to evaluate the acute dermal toxicity and 21-day repeated dermal toxicity of OLAF. In the acute dermal toxicity test, clinical observations were conducted to evaluate the toxicity, behaviour, and health of the animals for 14 consecutive days. Similarly, the clinical signs, body weight, haematological and biochemical parameters, histopathological changes and other indicators were also detected during the 21 days administration. For the dermal irritation test, single and multiple doses of OLAF (125 mg·kg−1 body weight) were administered to albino rabbits for 14 days (1 time/day). The irritation reaction on the skin of each albino rabbit was recorded and scored. Meanwhile, skin sensitisation to OLAF was conducted using guinea pigs for a period of 28 days. Results Suitable extraction conditions for OLAF (PBS concentration 0.01, pH of PBS 8.6, solid–liquid ratio 1:385 g·mL−1) were obtained using RSM. Under these conditions, the extraction rate and particle size of OLAF were 7.29% and 1290 nm, respectively. In the tests of acute dermal toxicity and 21-day repeated dermal toxicity, no mortality or significant differences were observed in terms of clinical signs, body weight, haematological parameters, biochemical parameters and anatomopathological analysis. With respect to the dermal irritation test and skin sensitisation test, no differences in erythema, oedema or other abnormalities were observed between treatment and control groups on gross and histopathological examinations. Conclusions The results of this study suggest that OLAF does not cause obvious toxicity, skin sensitisation or irritation in animals.