Application of polysaccharide biopolymers as natural adsorbent in sample preparation.

Preparing samples for analyses is perhaps the most important part to analyses. The varied functional groups present on the surface of biopolymers bestow them appropriate adsorption properties. Properties like biocompatibility, biodegradability, presence of different surface functional group, high porosity, considerable absorption capacity for water, the potential for modification, etc. turn biopolymers to promising candidates for varied applications. In addition, one of the most important parts of determination of an analyte in a matrix is sample preparation step and the efficiency of this step in solid phase extraction methods is largely dependent on the type of adsorbent used. Due to the unique properties of biopolymers they are considered an appropriate choice for using as sorbent in sample preparation methods that use from a solid adsorbent. Many review articles have been published on the application of diverse adsorbents in sample preparation methods, however despite the numerous advantages of biopolymers mentioned; review articles in this field are very few. Thus, in this paper we review the reports in different areas of sample preparation that use polysaccharides-based biopolymers as sorbents for extraction and determination of diverse organic and inorganic analytes.

Nano-architectural design of TiO2 for high performance photocatalytic degradation of organic pollutant: A review.

In the past several decades, significant efforts have been paid toward photocatalytic degradation of organic pollutants in environmental research. During the past years, titanium dioxide nano-architectures (TiO2 NAs) have been widely used in water purification applications with photocatalytic degradation processes under Uv/Vis light illumination. Photocatalysis process with nano-architectural design of TiO2 is viewed as an efficient procedure for directly channeling solar energy into water treatment reactions. The considerable band-gap values and the subsequent short life time of photo-generated charge carriers are showed among the limitations of this approach. One of these effective efforts is the using of oxidation processes with advance semiconductor photocatalyst NAs for degradation the organic pollutants under UV/Vis irradiation. Among them, nano-architectural design of TiO2 photocatalyst (such as Janus, yolk-shell (Y@S), hollow microspheres (HMSs) and nano-belt) is an effective way to improve oxidation processes for increasing photocatalytic activity in water treatment applications. In the light of the above issues, this study tends to provide a critical overview of the used strategies for preparing TiO2 photocatalysts with desirable physicochemical properties like enhanced absorption of light, low density, high surface area, photo-stability, and charge-carrier behavior. Among the various nanoarchitectural design of TiO2, the Y@S and HMSs have created a great appeal given their considerable large surface area, low density, homogeneous catalytic environment, favorable light harvesting properties, and enhanced molecular diffusion kinetics of the particles. In this review was summarized the developments that have been made for nano-architectural design of TiO2 photocatalyst. Additional focus is placed on the realization of interfacial charge and the possibility of achieving charge carriers separation for these NAs as electron migration is the extremely important factor for increasing the photocatalytic activity.

Adsorption of Cationic Dyes on a Magnetic 3D Spongin Scaffold with Nano-Sized Fe3O4 Cores.

The renewable, proteinaceous, marine biopolymer spongin is yet the focus of modern research. The preparation of a magnetic three-dimensional (3D) spongin scaffold with nano-sized Fe3O4 cores is reported here for the first time. The formation of this magnetic spongin-Fe3O4 composite was characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential thermal analysis (DTA) (TGA-DTA), vibrating sample magnetometer (VSM), Fourier-transform infrared spectroscopy (FTIR), and zeta potential analyses. Field emission scanning electron microscopy (FE-SEM) confirmed the formation of well-dispersed spherical nanoparticles tightly bound to the spongin scaffold. The magnetic spongin-Fe3O4 composite showed significant removal efficiency for two cationic dyes (i.e., crystal violet (CV) and methylene blue (MB)). Adsorption experiments revealed that the prepared material is a fast, high-capacity (77 mg/g), yet selective adsorbent for MB. This behavior was attributed to the creation of strong electrostatic interactions between the spongin-Fe3O4 and MB or CV, which was reflected by adsorption mechanism evaluations. The adsorption of MB and CV was found to be a function of pH, with maximum removal performance being observed over a wide pH range (pH = 5.5-11). In this work, we combined Fe3O4 nanoparticles and spongin scaffold properties into one unique composite, named magnetic spongin scaffold, in our attempt to create a sustainable absorbent for organic wastewater treatment. The appropriative mechanism of adsorption of the cationic dyes on a magnetic 3D spongin scaffold is proposed. Removal of organic dyes and other contaminants is essential to ensure healthy water and prevent various diseases. On the other hand, in many cases, dyes are used as models to demonstrate the adsorption properties of nanostructures. Due to the good absorption properties of magnetic spongin, it can be proposed as a green and uncomplicated adsorbent for the removal of different organic contaminants and, furthermore, as a carrier in drug delivery applications.

Voltammetric measurement of entacapone in the presence of other medicines against Parkinson's disease by a screen-printed electrode modified with sulfur-tin oxide nanoparticles.

A screen-printed electrode (SPE) is described modified with sulfur-tin oxide nanoparticles (S@SnO2NP) for the determination of entacapone (ENT) in the presence of other medicines against Parkinson's disease (PD). The S@SnO2NP was synthesized through the hydrothermal method and used in the modification of the SPE. The smart utilization of the S@SnO2NP and the SPE provided excellent properties such as high surface area and current density amplification by embedding an efficient sensing interface for highly selective electrochemical measurement. Under optimized experimental conditions, the anodic peak current related to the ENT oxidation onto the sensor surface at 0.46 V presented a linear response towards different ENT concentration sin the range 100 nM to 75 µM. The limit of detection (LOD) and electrochemical sensitivity were estimated to be 0.010 µM and 2.27 µA·µM-1·cm-2, respectively. The applicability of the sensor was evaluated during ENT determination in the presence of other conventional medicines againts, including levodopa (LD), carbidopa (CD), and pramipexole (PPX). The results of the analysis of human urine and pharmaceutical formulation as real samples using the developed sensor were in good agreement withre sults of high-performance liquid chromatography (HPLC) as a standard method. These findings demonstrated that the strategy based on the SPE is a cost-effective platform creating a promising candidate for practical determination of ENT in routine clinical testing.Graphical abstract.

Evaluation radioprotective effect of curcumin conjugated albumin nanoparticles.

In this research, curcumin (CUR) conjugated albumin based nanoparticles (BSA-CUR) were designed for improvement and evaluation radioprotective effect of CUR. In this way, we have prepared BSA-CUR by covalently binding the CUR with BSA. Next, this synthesized prodrug was evaluated for physical and chemical properties by Fourier-transform infrared (FTIR), Dynamic light scattering (DLS), Transmission electron microscopy (TEM), Ultraviolet-visible (UV/Vis), and Differential scanning calorimetry (DSC) analysis. Furthermore, the chemical stability of designed prodrug was appraised. The result shows that the size of nanoparticles is 174.4 nm with a polydispersity index (PdI) of 0.191. The nanoparticles have a high loading capacity and show sustained release behavior. Loading of CUR to BSA not only could increase the chemical stability of CUR, but also could improve radioprotection efficacy of it's against X-Ray irradiation. The HHF-2 cells show 107% viability in the presence of BSA-CUR at a concentration of 50 µg/mL, whereas non-treated cells show 46% viability, under X-Ray irradiation. Also in vivo study results show that, four out of five mice have died when the mice irradiated by X-Ray and no received any treatment. Although, for a group that treated with BSA-CUR and also irradiated by X-Ray, median survival and survival rate was higher than CUR treated and control mice, and only two out of five mice have died. The result of this study proved that BSA-CUR can be used as a proficient vehicle for improving the potential radioprotective effect of CUR.

Functionalization of 3D Chitinous Skeletal Scaffolds of Sponge Origin Using Silver Nanoparticles and Their Antibacterial Properties.

Chitin, as one of nature's most abundant structural polysaccharides, possesses worldwide, high industrial potential and a functionality that is topically pertinent. Nowadays, the metallization of naturally predesigned, 3D chitinous scaffolds originating from marine sponges is drawing focused attention. These invertebrates represent a unique, renewable source of specialized chitin due to their ability to grow under marine farming conditions. In this study, the development of composite material in the form of 3D chitin-based skeletal scaffolds covered with silver nanoparticles (AgNPs) and Ag-bromide is described for the first time. Additionally, the antibacterial properties of the obtained materials and their possible applications as a water filtration system are also investigated.

Naturally pre-designed biomaterials: Spider molting cuticle as a functional crude oil sorbent.

Diverse fields of modern environmental technology are nowadays focused on the discovery and development of new sources for oil spill removal. An especially interesting type of sorbents is those of natural origin-biosorbents-as ready-to-use constructs with biodegradable, nontoxic, renewable and cost-efficient properties. Moreover, the growing problem of microplastic-related contamination in the oceans further encourages the use of biosorbents. Here, for the first time, naturally pre-designed molting cuticles of the Theraphosidae spider Avicularia sp. "Peru purple", as part of constituting a large-scale spider origin waste material, were used for efficient sorption of crude oil. Compared with currently used materials, the proposed biosorbent of spider cuticular origin demonstrates excellent ability to remain on the water surface for a long time. In this study the morphology and hydrophobic features of Theraphosidae cuticle are investigated for the first time. The unique surface morphology and very low surface free energy (4.47 ± 0.08 mN/m) give the cuticle-based, tube-like, porous biosorbent excellent oleophilic-hydrophobic properties. The crude oil sorption capacities of A. sp. "Peru purple" molt structures in sea water, distilled water and fresh water were measured at 12.6 g/g, 15.8 g/g and 16.6 g/g respectively. These results indicate that this biomaterial is more efficient than such currently used fibrous sorbents as human hairs or chicken feathers. Four cycles of desorption were performed and confirmed the reusability of the proposed biosorbent. We suggest that the oil adsorption mechanism is related to the brush-like and microporous structure of the tubular spider molting cuticles and may also involve interaction between the cuticular wax layers and crude oil.

Mn(VO3)2 Nanorods: Its Green Synthesis and Photocatalytic Properties with the Aid of Polysorbate as the Polymeric Capping Agent.

The aim of the present study is to develop a simple and convenient co-precipitation method to synthesize Mn(VO3)2 nanorods with the aid of polysorbate as the polymeric capping agent in an aqueous environment. The energy-dispersive X-ray spectroscopy, X-ray diffraction, scanning electron microscopy, diffuse reflectance spectroscopy, and vibrating-sample magnetometer techniques were applied to characterize chemical structure, morphology, and optical properties of nanorods. According to the XRD and SEM results, various polysorbate has direct impact on the morphology and crystal size. The photocatalytic performance of the synthesized Mn(VO3)2 nanorods was evaluated by monitoring the photodegradation of methylene blue under UV light irradiation. Moreover, the influences of various parameters, such as nanorods size, various dyes, and reaction pH on the photocatalytic stability were studied.

A nanocomposite prepared from reduced graphene oxide, gold nanoparticles and poly(2-amino-5-mercapto-1,3,4-thiadiazole) for use in an electrochemical sensor for doxorubicin.

A nanocomposite was prepared with reduced graphene oxide, gold nanoparticles and an electropolymerized film made from 2-amino-5-mercapto-1,3,4-thiadiazole. An electrochemical sensor for doxorubicin (DOX) was constructed by modifying a glassy carbon electrode (GCE) with the nanocomposite. The modified GCE was studied by electrochemical techniques which showed it to enable highly sensitive sensing of DOX. Response (typically measured at a typical working potential of -0.56 V vs. Ag/AgCl) is linear in the 30 pM to 30 nM and 30 nM to 30 µM DOX concentration ranges, with a limit of detection (LOD) of 9 pM (at an S/N ratio of 3). The method was applied to the determination of DOX in serum and gave recoveries that ranged between 92 and 108%. Graphical abstract A combination of materials consisting of reduced graphene oxide (rGO), gold nanoparticles (AuNPs) and an electropolymerized film of 2-amino-5-mercapto-1,3,4-thiadiazole (poly-AMT, PAMT) is described. The nanocomposite was placed on a glassy carbon elkectrode (GCE) in order to fabricate an electrochemical sensor for doxorubicin (DOX).

A nanocomposite consisting of reduced graphene oxide and electropolymerized ß-cyclodextrin for voltammetric sensing of levofloxacin.

A glassy carbon electrode (GCE) was modified with a nanocomposite prepared from polymerized ß-cyclodextrin (ß-CD) and reduced graphene oxide (rGO). The modified GCE is shown to enable the voltammetric determination of traces of levofloxacin (LEV) by various electrochemical techniques. Experimental factors affecting the results including the amount of the substrates in preparation of the nanocomposite, accumulation time, the scan rate and pH value of the electrolyte were optimized. The modified GCE, best operated at a working potential of 1.00 V (vs. Ag/AgCl), has two linear response ranges, one for low LEV concentrations (100 pmol L-1 to 100 nmol L-1), and one for higher LEV concentrations (100 nmol L-1 to 100 µmol L-1). The limit of detection and sensitivity are calculated to be 30 pmol L-1 and 467.33 nA µmol L-1 cm-2, respectively. The modified GCE demonstrates a number of advantages such as high sensitivity and selectivity, low LOD, excellent reproducibility, high surface-to-volume ratio, and good electrocatalytic activity towards LEV. The sensor was successfully applied to the determination of LEV in spiked human serum samples. Graphical abstract.

Electrochemical determination of the antipsychotic medication clozapine by a carbon paste electrode modified with a nanostructure prepared from titania nanoparticles and copper oxide.

A nanostructure was prepared from titania nanoparticles and copper oxide (TiO2NP@CuO) and used to modify a carbon paste electrode (CPE). The modified CPE is shown to enable sensitive voltammetric determination of the drug clozapine (CLZ). The sensor was characterized by various techniques and some key parameters were optimized. Under the optimum conditions and at a working potential of 0.6 V (vs. Ag/AgCl), the modified CPE has two linear response ranges, one from 30 pmol L-1 to 4 nmol L-1 of CLZ, the other from 4 nmol L-1 to 10 µmol L-1. The detection limit is as low as 9 pM. The transfer coefficient (α) and catalytic rate constant (kcat) were calculated and the reliability of the sensor was estimated for CLZ sensing in real samples where it gave satisfactory results. Graphical abstract Applicability of the TiO2NP@CuO nanostructures in fabrication of an efficient clozapine (CLZ) sensor based on the use of a carbon paste electrode.

An electrochemical immunosensor based on poly p-phenylenediamine and graphene nanocomposite for detection of neuron-specific enolase via electrochemically amplified detection.

In this work, a label-free electrochemical immunosensor was constructed on the base of poly p-phenylenediamine (PPD) and GR nanocomposite (PPD-GR). Screen-printed electrodes modified with PPD-GR nanocomposite and applied to advance enzyme-free and label free electrochemical immunosensor for detection of protein biomarker neuron-specific enolase (NSE). It was found that the PPD-GR nanocomposite exhibits excellent electrocatalytic activity towards ascorbic acid (AA) oxidation as analytical signal based on EC' mechanism. Due to the excellent electrocatalytic activity of PPD-GR nanocomposite, determination of NSE antigen was based on its obstruction to the electrocatalytic oxidation of AA after binding to the surface of electrode through interaction with the anti-NSE. The proposed immunosensor exhibited a wide linear range of 1.0-1000 ng mL-1, with a low detection limit of 0.3 ng mL-1. Furthermore, the proposed immunosensor were successfully used for the determination of NSE antigen in human serum samples.

Electrochemical immunosensor for the breast cancer marker CA 15-3 based on the catalytic activity of a CuS/reduced graphene oxide nanocomposite towards the electrooxidation of catechol.

The authors report on an electrochemical immunosensor for the tumor marker carbohydrate antigen 15-3 (CA15-3). It is based on the use of a composite consisting of reduced graphene oxide (RGO) and copper sulfide (CuS) that was placed on a screen-printed graphite electrode. The electrode shows excellent activity towards the oxidation of catechol acting as an electrochemical probe, best at a working potential of 0.16 V. The electrode was modified with antibody against CA15-3. Once the analyte (CA15-3) binds to the surface of the electrode, the response to catechol is reduced. The assay has a linear response in the 1.0-150 U mL-1 CA15-3 concentration range, with a 0.3 U mL-1 lower detection limit and a sensitivity of 1.88 µA µM-1 cm-2. The immunosensor also shows good reproducibility (2.7%), stability (95% of the initial values after storing for four weeks). The method was successfully applied to the determination of CA15-3 in serum samples, and results were found to compare well to those obtained by an ELISA. Conceivably, this nanocomposite based detection scheme has a wider scope and may be applied to numerous other immunoassays. Graphical abstract A label-free electrochemical immunosensor based on copper sulfides/graphene nanocomposites was developed for enzyme-free determination of CA15-3 biomarker. This immunosensor can be utilized as a tool to detect of CA15-3 in real samples.

Magnetic N-doped carbon derived from mixed ligands MOF as effective electrochemiluminescence coreactor for performance enhancement of SARS-CoV-2 immunosensor.

COVID-19 as an infectious disease with rapid transmission speed is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), so, early and accurate diagnostics of COVID-19 is quite challenging. In this work, the selective and sensitive self-enhanced ECL method to detect of SARS-CoV-2 protein was designed with magnetic N-doped carbon derived from dual-ligand metal-organic frameworks (MOF) (CoO@N-C) with the primary and tertiary amino groups as a novel coreactant that covalently combined with Ru(bpy)2(phen-NH2)2+ as electrochemiluminescence (ECL) emitter. Mixed-ligand strategy and selected nitrogen-containing ligands, 4,4',4''-((1,3,5-triazine-2,4,6-triyl) tris-(azanediyl)) tribenzoic acid (H3TATAB) with 2-aminoterephthalic acid (BDC-NH2) were used for synthesis of the proposed MOF. Also, magnetic CoO@N-C with high synergistically charge transfer kinetics and good stability can be used as an effective platform/coreactor on the ITO electrode which load more Ru-complex as signal producing compound and SARS-CoV-2 N protein antibody to increase the sensitivity of the immunosensor. Furthermore, (CoO@N-C) as coreactor improved the ECL signal of the Ru (II)-complex more than 2.1 folds compared to tripropylamine. In view of these competences, the novel "on-off" ECL biosensor performed with great stability and repeatability for detection of SARS-CoV-2 protein, which exhibited a broad linearity from 8 fg. mL-1 to 4 ng. mL-1 (6 order of magnitude) and an ultra-low limit of detection 1.6 fg. mL-1. Finally, this proposed method was successfully applied to detect of SARS-CoV-2 N protein in serum sample with satisfactory results, indicating the proposed immunosensor has the potential for quick analysis of SARS-CoV-2.

Hierarchical machine learning model predicts antimicrobial peptide activity against Staphylococcus aureus.

Introduction: Staphylococcus aureus is a dangerous pathogen which causes a vast selection of infections. Antimicrobial peptides have been demonstrated as a new hope for developing antibiotic agents against multi-drug-resistant bacteria such as S. aureus. Yet, most studies on developing classification tools for antimicrobial peptide activities do not focus on any specific species, and therefore, their applications are limited. Methods: Here, by using an up-to-date dataset, we have developed a hierarchical machine learning model for classifying peptides with antimicrobial activity against S. aureus. The first-level model classifies peptides into AMPs and non-AMPs. The second-level model classifies AMPs into those active against S. aureus and those not active against this species. Results: Results from both classifiers demonstrate the effectiveness of the hierarchical approach. A comprehensive set of physicochemical and linguistic-based features has been used, and after feature selection steps, only some physicochemical properties were selected. The final model showed the F1-score of 0.80, recall of 0.86, balanced accuracy of 0.80, and specificity of 0.73 on the test set. Discussion: The susceptibility to a single AMP is highly varied among different target species. Therefore, it cannot be concluded that AMP candidates suggested by AMP/non-AMP classifiers are able to show suitable activity against a specific species. Here, we addressed this issue by creating a hierarchical machine learning model which can be used in practical applications for extracting potential antimicrobial peptides against S. aureus from peptide libraries.

Nano-architecture of MOF (ZIF-67)-based Co3O4 NPs@N-doped porous carbon polyhedral nanocomposites for oxidative degradation of antibiotic sulfamethoxazole from wastewater.

Co3O4 NPs in N-doped porous carbon (Co3O4 NPs@N-PC) materials were prepared by one-pot pyrolysis of a ZIF-67 powder under N2 atmosphere and followed by oxidation under air atmosphere (200 °C) toward promotion catalytic activity and activation of peroxymonosulfate (PMS) to degradation sulfamethoxazole (SMZ). 2-methylimidazole was used as a nitrogen source and a competitive ligand for the synthesis of Co3O4 NPs@N-PC, which in addition to affecting nucleation and growth of the crystal, promotes the production of active Co-N sites. Co3O4 NPs@N-PC nano-architecture has high specific surface areas (250 m2 g-1) and is a non-toxic, effective and stable PMS activator. The effect of operating parameters including SMZ concentration, catalyst dosage, temperature and pH in the presence of Co3O4 NPs@N-PC was investigated. The Co3O4 NPs@N-PC composite showed superior performance in activating PMS over a wide range of pH (2-10) and different temperatures so that complete degradation of SMZ (50 µM, 100 mL) was achieved within 15 min. The role of Co2+/Co3+ redox system in the mechanism before and after PMS activation was determined using XPS analysis. Surface-generated radicals led to the degradation of SMZ, in which the SMZ degradation rate attained 0.21 min-1 with the mineralization of 36.8%. The feasible degradation mechanism of SMZ was studied in the presence of different scavengers and it was revealed that the degradation reaction proceeds from the radical/non-radical pathway and in this process most of the SO4- and OH radicals are dominant. The recoverability and reuse of Co3O4 NPs@N-PC were evaluated to confirm its stability and potential for SMZ degradation and it was observed that the catalyst maintains its catalytic power for at least 5 cycles.

Applicability of a Green Nanocomposite Consisted of Spongin Decorated Cu2WO4(OH)2 and AgNPs as a High-Performance Aptasensing Platform in Staphylococcus aureus Detection.

This study reports the synthesis of a nanocomposite consisting of spongin and its applicability in the development of an aptasensing platform with high performance. The spongin was carefully extracted from a marine sponge and decorated with copper tungsten oxide hydroxide. The resulting spongin-copper tungsten oxide hydroxide was functionalized by silver nanoparticles and utilized in electrochemical aptasensor fabrication. The nanocomposite covered on a glassy carbon electrode surface amplified the electron transfer and increased active electrochemical sites. The aptasensor was fabricated by loading of thiolated aptamer on the embedded surface via thiol-AgNPs linkage. The applicability of the aptasensor was tested in detecting the Staphylococcus aureus bacterium as one of the five most common causes of nosocomial infectious diseases. The aptasensor measured S. aureus under a linear concentration range of 10-108 colony-forming units per milliliter and a limit of quantification and detection of 12 and 1 colony-forming unit per milliliter, respectively. The highly selective diagnosis of S. aureus in the presence of some common bacterial strains was satisfactorily evaluated. The acceptable results of the human serum analysis as the real sample may be promising in the bacteria tracking in clinical samples underlying the green chemistry principle.

Utility of Biogenic Iron and Its Bimetallic Nanocomposites for Biomedical Applications: A Review.

Nanotechnology mainly deals with the production and application of compounds with dimensions in nanoscale. Given their dimensions, these materials have considerable surface/volume ratios, and hence, specific characteristics. Nowadays, environmentally friendly procedures are being proposed for fabrication of Fe nanoparticles because a large amount of poisonous chemicals and unfavorable conditions are needed to prepare them. This work includes an inclusive overview on the economical and green procedures for the preparation of such nanoparticles (flower, fruits, tea, carbohydrates, and leaves). Pure and bimetallic iron nanoparticles, for instance, offer a high bandwidth and excitation binding energy and are applicable in different areas ranging from antibacterial, anticancer, and bioimaging agents to drug delivery systems. Preparation of nano-sized particles, such as those of Fe, requires the application of high quantities of toxic materials and harsh conditions, and naturally, there is a tendency to develop more facile and even green pathways (Sultana, Journal of Materials Science & Technology, 2013, 29, 795-800; Bushra et al., Journal of hazardous materials, 2014, 264, 481-489; Khan et al., Ind. Eng. Chem. Res., 2015, 54, 76-82). This article tends to provide an overview on the reports describing green and biological methods for the synthesis of Fe nanoparticles. The present review mainly highlights selenium nanoparticles in the biomedical domain. Specifically, this review will present detailed information on drug delivery, bioimaging, antibacterial, and anticancer activity. It will also focus on procedures for their green synthesis methods and properties that make them potential candidates for various biomedical applications. Finally, we provide a detailed future outlook.

Supercritical Fluid Extraction of Pesticides and Insecticides from Food Samples and Plant Materials.

The principal intention of this study is presenting the attempts carried out for extracting, separating, and determining of the pesticide and insecticide residues existing in food and plant samples. In this regard, a set of content, including the explanations about the supercritical fluid extraction (SFE), supercritical fluid chromatography, and various types of pesticides are indicated. Besides, the parameters affecting the pesticides extraction composed of temperature, pressure, modifier, drying agent, and so on are discussed. Also, examples of insecticides extraction by SFE technique as an important subset of pesticides are indicated. Along with these items, some interesting works, concerning the innovations implemented in the field of SFE of pesticide and insecticide residues from foodstuff and plants are depicted.

Earlier diagnoses of acute leukemia by a sandwich type of electrochemical aptasensor based on copper sulfide-graphene composite.

Due to high affinity and specificity of aptamers, they are widely considered for construction of aptasensor to specific recognizing of analytes in biological complex matrix. So, in this work we design a high selective and sensitive aptasensor for leukemia cancer cells (CCRF-CEM) via superior catalytic effect of copper sulfide-graphene (CuS-GR) nanocomposite as label and Au-GR nanocomposite as sensing platform. The CuS-GR nano-composite (label component) is CuS nanoparticles that wrapping on graphene sheets. Its catalytic activity (CuS-GR) increases the current of sensor in parallel with adding of CCRF-CEM and provide sensitive detection of analytes. The detailed of signal amplification and effect on the aptasensor performance completely discussed. This sensor has a linear range of 50-1 × 106 cell mL-1, with a limit of detection of 18 cell mL-1. Also, the developed aptasensor has a significance specificity, high sensitivity and accuracy. It was used for the identification of CCRF-CEM cells in blood samples.