Performance of ginger constituents against SARS-CoV-2 virus: A therapeutic and theoretical approach.

In the present research, ginger extracted compounds, namely; Gingerol {(1-[4'-hydroxy-3'-methoxyphenyl]-5-hydroxy-3-decanone} (1), Zingerone {(4-(4-Hydroxy-3-methoxyphenyl)-2-butanone)} (2), and Shogoals {(E)-1-(4-Hydroxy-3- methoxyphenyl) dec-4-en-3-one)} (3) have been investigated as SARS-Cov-2 inhibitors. The interaction of extracted compounds with the virus's spikes may restrict the virus's reproduction or give time to the body's immune system to detect viruses, consequently producing appropriate antibodies. Gaussian 09 with a 6-311G (d, p) basis set, UCA FUKUI, MGL implement, DSV, and LigPlus software were utilized. The active sites for adsorption were identified using the total electron density (TED), FUKUI function, and Millikan charges. Furthermore, docking analysis clearly showed that the inhibition of viral replication depends on binding energy (Eb) and ligand efficiency (LE). A docking study revealed that the inhibition ability of the studied compounds on SARS-CoV-2 was in the order of 2 > 3 > 1.

A density functional theory study on the potential application of Ni and Co doped ZnO nanosheets as a carrier for ciclopirox anticancer drug.

The Ni and Co doping effect on the ciclopirox (CPX) drug delivery performance of a ZnO nanosheet (ZnO-NS) was investigated theoretically. Doping Ni and Co metals into the ZnO-NS increased the adsorption energy of CPX from -7.9 to -27.4 and -31.7 kcal/mol, respectively. The CPX adsorption reduced the ZnO-NS gap (Eg) from 3.81 to 3.46 eV, while the CPX adsorption reduced the Eg of the Ni- and Co-doped ZnO-NS from 2.74 and 2.68 eV to 1.87 and 1.71 eV, respectively. The CPX adsorption performance increased after doping process. A drug release mechanism was introduced in cancerous tissues based on the PH. .

Molecular docking, drug-likeness and DFT study of some modified tetrahydrocurcumins as potential anticancer agents.

The present study utilized molecular docking and density functional theory (DFT) approaches, and ADMET (absorption, distribution, metabolism, excretion, and toxicity) properties to investigate the binding interactions, reactivity, stability, and drug-likeness of curcumin (1), tetrahydrocurcumin (2), and tetrahydrocurcumin derivatives (3-6) as potential anti-cancer agents. MGL (Molecular Graphic Laboratory) and Discovery Studio Visualizer (DSV) software employed for docking studies. Pharmacokinetic and pharmacodynamic (ADME-Tox) analyses were conducted using SwissADME and pKCSM web servers. Total Electron Density (TED) measurements identified molecular adsorption sites, considering various factors, including quantum chemical characteristics, to assess compound effectiveness using DFT method implanted in the Gaussian software. The binding energy (Eb) from docking simulations was used to evaluate inhibitory potential. ADMET analysis suggested favorable oral bioavailability and pharmacokinetics for all studied substances, excluding compound 4. DFT and docking investigations highlighted compounds 1, 2, and 6 as optimal scaffolds for drug design based on in silico screening tests.

Angiogenesis and prostate cancer: MicroRNAs comes into view.

Angiogenesis, the formation of new blood vessels, is an important stage in the growth of cancer. Extracellular matrix, endothelial cells, and soluble substances must be carefully coordinated during the multistep procedure of angiogenesis. Inducers and inhibitors have been found to control pretty much every phase. In addition to benign prostatic hyperplasia, prostatic intraepithelial neoplasia, and angiogenesis have a critical role in the initiation and progression of prostate cancer. MicroRNA (miRNA) is endogenous, short, non-coding RNA molecules of almost 22 nucleotides play a role in regulating cellular processes and regulating several genes' expression. Through controlling endothelial migration, differentiation, death, and cell proliferation, miRNAs have a significant function in angiogenesis. A number of pathological and physiological processes, particularly prostate cancer's emergence, depend on the regulation of angiogenesis. Investigating the functions played with miRNAs in angiogenesis is crucial because it might result in the creation of novel prostate cancer therapies that entail regulating angiogenesis. The function of several miRNAs and its targeting genes engaged in cancer of the prostate angiogenesis will be reviewed in this review in light of the most recent developments. The potential clinical utility of miRNAs potentially a novel therapeutic targets will also be explored, as well as their capacity to control prostate cancer angiogenesis and the underlying mechanisms.

THE ROLE OF OXIDATIVE STRESS IN PATIENTS WITH CHRONIC KIDNEY DISEASE.

OBJECTIVE: The aim: To study the role of oxidative stress in patients with chronic kidney disease. PATIENTS AND METHODS: Materials and methods: By evaluating MDA and GSH in the serum, we tried to find out how oxidative stress affects CKD patients with end-stage renal dysfunction (ESRD). The study included 90 patients with ESRD disease whom were under hemodialysis treatment, and 30 healthy control people. RESULTS: Results: Urea, creatinine, and MDA levels were noticeably greater in ESRD patients compared to controls, but GSH levels were noticeably lower. In conclusion, oxidative stress can cause more problems to these patients by its involvement in the appearance of metabolic and cardiovascular diseases. CONCLUSION: Conclusions: Furthermore, GSH was reduced significantly in ESRD patients and associated negatively with the level of MDA. This indicates the strong involve¬ment of antioxidants, especially GSH, in the development of oxidative stress in ESRD patients.

A systematic review of the protective effects of silymarin/silibinin against doxorubicin-induced cardiotoxicity.

PURPOSE: Although doxorubicin chemotherapy is commonly applied for treating different malignant tumors, cardiotoxicity induced by this chemotherapeutic agent restricts its clinical use. The use of silymarin/silibinin may mitigate the doxorubicin-induced cardiac adverse effects. For this aim, the potential cardioprotective effects of silymarin/silibinin against the doxorubicin-induced cardiotoxicity were systematically reviewed. METHODS: In this study, we performed a systematic search in accordance with PRISMA guideline for identifying all relevant studies on "the role of silymarin/silibinin against doxorubicin-induced cardiotoxicity" in different electronic databases up to June 2022. Sixty-one articles were obtained and screened based on the predefined inclusion and exclusion criteria. Thirteen eligible papers were finally included in this review. RESULTS: According to the echocardiographic and electrocardiographic findings, the doxorubicin-treated groups presented a significant reduction in ejection fraction, tissue Doppler peak mitral annulus systolic velocity, and fractional shortening as well as bradycardia, prolongation of QT and QRS interval. However, these echocardiographic abnormalities were obviously improved in the silymarin plus doxorubicin groups. As well, the doxorubicin administration led to induce histopathological and biochemical changes in the cardiac cells/tissue; in contrast, the silymarin/silibinin co-administration could mitigate these induced alterations (for most of the cases). CONCLUSION: According to the findings, it was found that the co-administration of silymarin/silibinin alleviates the doxorubicin-induced cardiac adverse effects. Silymarin/silibinin exerts its cardioprotective effects via antioxidant, anti-inflammatory, anti-apoptotic activities, and other mechanisms.

The interactions of docetaxel with tumor microenvironment.

There are several interactions within the tumor microenvironment (TME) that affect the response of cancer cells to therapy. There are also a large number of cells and secretions in TME that increase resistance to therapy. Following the release of immunosuppressive, pro-angiogenic, and metastatic molecules by certain cells such as tumor-associated macrophages (TAMs), cancer-associated fibroblasts (CAFs), and cancer cells, immune evasion, angiogenesis, and metastasis may be induced. However, natural killer (NK) cells and cytotoxic CD8 + T lymphocytes (CTLs) can responsively release anticancer molecules. In addition, anticancer drugs can modulate these cells and their interactions in favor of either cancer resistance or therapy. Docetaxel belongs to taxanes, a class of anti-tumor drugs, which acts through the polymerization of tubulin and the induction of cell cycle arrest. Also, it has been revealed that taxanes including docetaxel affect cancer cells and the other cells within TME through some other mechanisms such as modulation of immune system responses, angiogenesis, and metastasis. In this paper, we explain the basic mechanisms of docetaxel interactions with malignant cells. Besides, we review the diverse effects of docetaxel on TME and cancer cells in consequence. Lastly, the modulatory effects of docetaxel alone or in conjunction with other anticancer agents on anti-tumor immunity, cancer cell resistance, angiogenesis, and metastasis will be discussed.

Exploring the role of 2D-C2N monolayers in potassium ion batteries.

CONTEXT: In recent years, undivided attention has been given to the unique properties of layered nitrogenated holey graphene (C2N) monolayers (C2NMLs), which have widespread applications (e.g., in catalysis and metal-ion batteries). Nevertheless, the scarcity and impurity of C2NMLs in experiments and the ineffective technique of adsorbing a single atom on the surface of C2NMLs have significantly limited their investigation and thus their development. Within this research study, we proposed a novel model, i.e., atom pair adsorption, to inspect the potential use of a C2NML anode material for KIBs through first-principles (DFT) computations. The maximum theoretical capacity of K ions reached 2397 mA h g-1, which was greater in contrast with that of graphite. The results of Bader charge analysis and charge density difference revealed the creation of channels between K atoms and the C2NML for electron transport, which increased the interactions between them. The fast process of charge and discharge in the battery was due to the metallicity of the complex of C2NML/K ions and because the diffusion barrier of K ions on the C2NML was low. Moreover, the C2NML has the advantages of great cycling stability and low open-circuit voltage (approximately 0.423 V). The current work can provide useful insights into the design of energy storage materials with high efficiency. METHODS: In this research, we used B3LYP-D3 functional and 6-31 + G* basis with GAMESS program to calculate adsorption energy, open-circuit voltage, and maximum theoretical capacity of K ions on the C2NML.

Molecular modeling for sensing of cisplatin drug by graphdiyne: electronic study via DFT.

CONTEXT: By utilizing first-principles calculations, we studied the electronic properties of graphdiyne nanosheet (GDY) and its Si-doped counterpart, Si-GDY. Both GDY and Si-GDY sheet surfaces were examined for the drug cisplatin (CP) adsorption using adsorption energy, charge transfer, and changes in electrical conductivity as indicators. Pure GDY has little affinity for CP, according to this study. Only 7.83% of the GDY surface's bandwidth energy changed after CP adsorption. CP on Si-GDY has a gaseous energy value of -18.75 kcal/mol and an aqueous energy value of - 49.39 kcal/mol. METHODS: The prescribed medications' water-phase solubility is determined by their solvation energy value. These charges are transferred between CP and the Si-GDY sheet, which is extremely positively charged, and this gives CP the necessary binding energy. After CP adsorption, electrical conductivity of Si-GDY increased by approximately 19.01%.

Inhibitory behavior and adsorption of asparagine dipeptide amino acid on the Fe(111) surface.

CONTEXT: The inhibitory effect of asparagine (Asn) and its derivatives on iron (Fe) corrosion was studied by performing density functional theory (DFT) calculations. In this paper, the global and local reactivity descriptors of Asn in the protonated and neutral forms were evaluated. Also, the changes in reactivity were investigated when dipeptides were combined with Asn. Due to the increase in the reaction centers within their molecular structure, there was an enhancement in the inhibitory effect of these dipeptides. Moreover, the adsorption energies (Eads) and the adsorption configurations of Asn and small peptides (SPs) with most stability were determined on the surface of Fe(111). It was found that dipeptides had a chemical adsorption on these substrates. In the protonated forms, there was an enhancement in the absolute values of Eads between the inhibitors and the Fe(111) surfaces. Peptides were more likely to be adsorbed on the Fe surfaces, showing the great inhibitory effect of these moieties. The results of the current research demonstrate the possibility of utilizing SPs as efficient "green" corrosion inhibitors. METHODS: DFT computations were undertaken by employing the BIOVIA Material Studio with B3LYP-D3 functional and 6-31 + G* basis set. The theoretical evaluation of the inhibitory effect of asparagine (Asn) dipeptides, and the potential analysis of small peptides to protect against the corrosion of Fe, was done.

Multifaceted role of NF-κB in hepatocellular carcinoma therapy: Molecular landscape, therapeutic compounds and nanomaterial approaches.

The predominant kind of liver cancer is hepatocellular carcinoma (HCC) that its treatment have been troublesome difficulties for physicians due to aggressive behavior of tumor cells in proliferation and metastasis. Moreover, stemness of HCC cells can result in tumor recurrence and angiogenesis occurs. Another problem is development of resistance to chemotherapy and radiotherapy in HCC cells. Genomic mutations participate in malignant behavior of HCC and nuclear factor-kappaB (NF-κB) has been one of the oncogenic factors in different human cancers that after nuclear translocation, it binds to promoter of genes in regulating their expression. Overexpression of NF-κB has been well-documented in increasing proliferation and invasion of tumor cells and notably, when its expression enhances, it induces chemoresistance and radio-resistance. Highlighting function of NF-κB in HCC can shed some light on the pathways regulating progression of tumor cells. The first aspect is proliferation acceleration and apoptosis inhibition in HCC cells mediated by enhancement in expression level of NF-κB. Moreover, NF-κB is able to enhance invasion of HCC cells via upregulation of MMPs and EMT, and it triggers angiogenesis as another step for increasing spread of tumor cells in tissues and organs. When NF-κB expression enhances, it stimulates chemoresistance and radio-resistance in HCC cells and by increasing stemness and population of cancer-stem cells, it can provide the way for recurrence of tumor. Overexpression of NF-κB mediates therapy resistance in HCC cells and it can be regulated by non-coding RNAs in HCC. Moreover, inhibition of NF-κB by anti-cancer and epigenetic drugs suppresses HCC tumorigenesis. More importantly, nanoparticles are considered for suppressing NF-κB axis in cancer and their prospectives and results can also be utilized for treatment of HCC. Nanomaterials are promising factors in treatment of HCC and by delivery of genes and drugs, they suppress HCC progression. Furthermore, nanomaterials provide phototherapy in HCC ablation.

Doxorubicin-loaded micelles in tumor cell-specific chemotherapy.

Nanomedicine is a field that combines biology and engineering to improve disease treatment, particularly in cancer therapy. One of the promising techniques utilized in this area is the use of micelles, which are nanoscale delivery systems that are known for their simple preparation, high biocompatibility, small particle size, and the ability to be functionalized. A commonly employed chemotherapy drug, Doxorubicin (DOX), is an effective inhibitor of topoisomerase II that prevents DNA replication in cancer cells. However, its efficacy is frequently limited by resistance resulting from various factors, including increased activity of drug efflux transporters, heightened oncogenic factors, and lack of targeted delivery. This review aims to highlight the potential of micelles as new nanocarriers for delivering DOX and to examine the challenges involved with employing chemotherapy to treat cancer. Micelles that respond to changes in pH, redox, and light are known as stimuli-responsive micelles, which can improve the targeted delivery of DOX and its cytotoxicity by facilitating its uptake in tumor cells. Additionally, micelles can be utilized to administer a combination of DOX and other drugs and genes to overcome drug resistance mechanisms and improve tumor suppression. Furthermore, micelles can be used in phototherapy, both photodynamic and photothermal, to promote cell death and increase DOX sensitivity in human cancers. Finally, the alteration of micelle surfaces with ligands can further enhance their targeted delivery for cancer suppression.

Evaluation of a biosensor-based graphene oxide-DNA nanohybrid for lung cancer.

Lung cancer is nowadays among the most prevalent diseases worldwide and features the highest mortality rate among various cancers, indicating that early diagnosis of the disease is of paramount importance. Given that the conventional methods of cancer detection are expensive and time-consuming, special attention has been paid to the provision of less expensive and faster techniques. In recent years, the dramatic advances in nanotechnology and the development of various nanomaterials have led to activities in this context. Recent studies indicate that the graphene oxide (GO) nanomaterial has high potential in the design of nano biosensors for lung cancer detection owing to its unique properties. In the current article, a nano biosensor based on a DNA-GO nanohybrid is introduced to detect deletion mutations causing lung cancer. In this method, mutations were detected using a FAM-labeled DNA probe with fluorescence spectrometry. GO was synthesized according to Hummers' method and examined and confirmed using Fourier Transform Infrared (FT-IR) Spectrometry and UV-vis spectrometry methods and Transmission Electron Microscopy (TEM) images.

Autophagy as a self-digestion signal in human cancers: Regulation by microRNAs in affecting carcinogenesis and therapy response.

Autophagy is defined as a "self-digestion" signal, and it is a cell death mechanism its primary function is degrading toxic agents and aged organelles to ensure homeostasis in cells. The basic leve ls of autophagy are found in cells, and when its levels exceed to standard threshold, cell death induction is observed. Autophagy dysregulation in cancer has been well-documented, and regulation of this pathway by epigenetic factors, especially microRNAs (miRNAs), is interesting and noteworthy. miRNAs are considered short endogenous RNAs that do not encode functional proteins, and they are essential regulators of cell death pathways such as apoptosis, necroptosis, and autophagy. Accumulating data has revealed miRNA dysregulation (upregulation or downregulation) during tumor progression, and their therapeutic manipulation provides new insight into cancer therapy. miRNA/autophagy axis in human cancers has been investigated an exciting point is the dual function of both autophagy and miRNAs as oncogenic and onco-suppressor factors. The stimulation of pro-survival autophagy by miRNAs can increase the survival rate of tumor cells and mediates cancer metastasis via EMT inductionFurthermore, pro-death autophagy induction by miRNAs has a negative impact on the viability of tumor cells and decreases their survival rate. The miRNA/autophagy axis functions beyond regulating the growth and invasion of tumor cells, and they can also affect drug resistance and radio-resistance. These subjects are covered in the current review regarding the new updates provided by recent experiments.

The association between prenatal exposure to polycyclic aromatic hydrocarbons and childhood intelligence: a systematic review of observational studies.

Exposure to polycyclic aromatic hydrocarbons (PAHs) during pregnancy has been associated with many adverse child health. However, the evidence on such associations with child brain development was not reviewed systemically. Therefore, in this study, we systemically reviewed the observational studies on prenatal exposure to PAHs and childhood intelligence quotient (IQ). The Meta-analyses Of Observational Studies in Epidemiology (MOOSE) guidelines were applied to perform this review. We systematically searched Scopus, PubMed, and Web of Science for all relevant articles published in English until 15 October 2022. The quality of retrieved studies was evaluated based on the Gascon et al. method. We retrieved a total of 351 citations through the initial search, of which an overall of six articles ([Formula: see text] participants) were included in our final review. The quality assessment indicated that four studies had excellent and two studies had good quality. Three reviewed studies reported a significant negative association between prenatal exposure to PAHs and children's IQ. One study reported that exposure to PAHs combined with material hardship was associated with lower child IQ and one study indicated lower child IQ through lower LINE1 DNA methylation-related maternal exposure to PAHs. However, another study did not observe a significant association between prenatal PAH exposure and child IQ. Overall, our review indicated that exposure to PAHs during pregnancy has an adverse impact on childhood IQ.

Application of zinc oxide nano-tube as drug-delivery vehicles of anticancer drug.

CONTEXT: Zinc oxide nano-tube (ZnONT) nano-structures, which possess chemical stability and non-toxicity in the human body, are considered promising for delivering different drugs. Within this work, we scrutinized the drug delivery capability of the ZnONT and its adsorptional properties as a drug delivery vehicle (DDV) for hydroxyurea (HU) as an anti-cancer drug through density functional theory along with the solvent impacts. Based on the optimized structures, it can be suggested that Zn atoms of ZnONT are the ideal sites on this nano-tube for the adsorption of HU. HU had a strong physical adsorption through the O atom of carbonyl groups onto the local pyramidal site of the ZnONT. At 1.96 Å and Ead of -39.28 kcal/mol, in the configuration which was favorable in terms of energy, there was an interaction between the O atoms of -C=O group of the drug and a Zn atom of the ZnONT. In order to scrutinize the excited state properties of the HU-ZnONT complex, we also examined the UV/Vis data of the HU/ZnONT interaction system. Following the adsorption of HU onto the surface of the ZnONT, there was a significant red-shift based on the maximum absorption wavelength, showing that the ZnONT is an ideal candidate for optic sensors in order to detect and monitor the drug molecule. HU could be released in the cancer tissues where pH was low based on the drug release mechanism. The current work thoroughly investigated the mechanism of interaction between the ZnONT and HU, showing that ZnONT can be used for the smart drug delivery of HU. Overall, the findings suggest that ZnONT could be used as an efficient drug-delivery system for the HU drug to treat various types of cancer. METHODS: In this work we used B3LYP-gCP-D3 functional and the basis set LANL2DZ on the transition metal (Zn) and the basis set cc-pVDZ on the others. GAMESS software program was employed for performing the calculations. we performed analyses, including charge transport, molecular electrostatic potential surface (MEP), energetic, electronic, natural bond orbitals (NBOs), and structural optimizations.

Theoretical Sensing Performance for Detection of Cyclophosphamide Drug by Using Aluminum Carbide (C3Al) Monolayer: a DFT Study.

Because nanomaterials are highly reactive and electronically sensitive towards a variety of drug molecules, they are thought of as efficient drug sensors. In the present research study, an aluminum carbide (C3Al) monolayer is employed and its interaction is examined with cyclophosphamide (CP) by performing DFT computations. The C3Al monolayer is highly reactive and sensitive towards CP according to the computations. CP interacts with the C3Al monolayer with the adsorption energy of -31.39 kcal/mol. A considerable charge transfer (CT) indicates an enhancement in the conductivity. Also, the charge density is explained based on the electron density differences (EDD). The decrease in CP/C3Al energy gap (Eg) by approximately 52.91% is due to the remarkable effect of adsorption on the LUMO and the HOMO levels. Therefore, due to the decrease in Eg which can generate an electrical signal, the electrical conductivity is considerably increased. These results suggest that the C3Al monolayer can be employed as a proper electronic drug sensor for CP. Also, the recovery time for the desorption process of CP form the surface of C3Al is 351 s at 598 K.

BeO nanotube as a promising material for anticancer drugs delivery system.

In this research, the application of BeO nanotube (BeONT) as a nanocarrier for Fluorouracil (5-FU) anticancer drug has been studied by density functional theory (DFT) approach. The method ωB97XD with 6-31 G** basis set were employed. A precise surface study, shows that there are two directions for 5-FU adsorption that did not deliver any of the imaginary frequency vibrational spectra, identifying that all relaxation structures are at the lowest energy level. Based on our calculations, the energy of adsorption for 5FU@BeONT structures are range -120 to -168 kJ/mol, in the gas phase and -395 to 4-00 kJ/mol in the aqueous phase. The highest and the lowest values of adsorption energy are both in strong physical adsorption. Due to receiving an electronic charge from 5-FU, BeONT exhibited a p-type semiconducting feature for all positions. In addition, based on natural bond orbital (NBO) analysis, the direction of charge transfer was from fluorine's σ orbitals of the drug to n* orbitals (O and Be atoms) of BeONT with a considerable amount of transferred energy. BeONT can be employed as a potential strong carrier for 5-FU drugs for practical purposes based on our findings.

Ketoprofen suppresses triple negative breast cancer cell growth by inducing apoptosis and inhibiting autophagy.

BACKGROUND: Triple-negative breast cancer (TNBC) is an invasive phenotype with undesirable clinical features, poor prognosis, and therapy resistance. Ketoprofen is a Non-steroidal anti-inflammatory drug (NSAID) with anti-tumor properties. AIM: To investigate the effects of Ketoprofen on apoptosis and autophagy in TNBC cell line MDA-MB-231. METHODS: The cytotoxic activity of Ketoprofen was assayed by the MTS method. Flowcytometry was utilized to measure the number of apoptotic MDA-MB-231 cells. The expression levels of apoptosis and autophagy markers, JAK2 and STAT3 were determined using quantitative real time-PCR (qRT-PCR) and western blotting methods. RESULTS: Ketoprofen significantly decreased the proliferation of MDA-MB-231 cells compared to control cells. It also considerably induced apoptosis and apoptotic markers in these cells in comparison to controls. Treating the MADA-MB-231 cell line with Ketoprofen had an inhibitory effect on autophagy markers in this cell line. The use of FasL, as a death ligand, and ZB4, as an antibody that blocks the extrinsic pathway of apoptosis, revealed the involvement of the extrinsic pathway in the apoptosis-stimulating effect of Ketoprofen in the MADA-MB-231 cell line. Ketoprofen also hindered the phosphorylation and activation of JAK2 and STAT molecules leading to the inhibition of the JAK/STAT pathway in this TNBC cell line. CONCLUSION: The outcomes of this study uncovered the anti-TNBC activity of Ketoprofen by inducing apoptosis and inhibiting viability and autophagy in MADA-MB-231 cells. Our data also suggested that Ketoprofen impedes apoptosis in TNBC cells by two different mechanisms including the induction of the extrinsic apoptotic pathway and inhibition of the JAK/STAT signaling.

Adsorption performance of Enterobacter cloacae towards U(VI) ion and application of Enterobacter cloacae/carbon nanotubes to preconcentration and determination of low-levels of U(VI) in water samples.

Keeping the high potential of some microorganisms in adsorption of radionuclides in view, the adsorption properties of Enterobacter cloacae towards uranium were attentively scrutinized, and then it was used for preconcentration of uranium in different samples, using Enterobacter cloacae/carbon nanotube composite. First, using ultrasonic agitation, the effects of operational factors on biosorption of uranium on the inactive Enterobacter cloacae were appraised and modeled by central composite design, and a comprehensive study was performed on the equilibrium, kinetics, thermodynamic, and selectivity aspects of biosorption. The optimization studies along with the evaluations of the adsorption properties revealed that Enterobacter cloacae have a high affinity for fast and selective biosorption of uranium ions, at pH 5.1. Second, the Enterobacter cloacae/carbon nanotube was synthesized, characterized, and utilized for preconcentration of uranium in different samples, using a mini-column packed with the composite. The optimization of operational factors on recovery of uranium, using the central composite design, showed that uranium can be quantitively adsorbed at a sample flow rate lower than 4.5 mL min-1 and the desorption could be accomplished with 3.0 mL HCl 0.6 M solution. Finally, the mini-column was exploited for preconcentration and determination of uranium in different samples. The results revealed the low detection limit (0.015 µg.L-1), high precision (RSDs ≤3.92%), and good accuracy of the proposed procedure.