Displaying publications 181 - 200 of 280 in total

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  1. Allyl triphenyl phosphonium bromide based DES-functionalized carbon nanotubes for the removal of mercury from water
    AlOmar MK, Alsaadi MA, Hayyan M, Akib S, Ibrahim M, Hashim MA
    Chemosphere, 2017 Jan;167:44-52.
    PMID: 27710842 DOI: 10.1016/j.chemosphere.2016.09.133
    Recently, deep eutectic solvents (DESs) have shown their new and interesting ability for chemistry through their involvement in variety of applications. This study introduces carbon nanotubes (CNTs) functionalized with DES as a novel adsorbent for Hg(2+) from water. Allyl triphenyl phosphonium bromide (ATPB) was combined with glycerol as the hydrogen bond donor (HBD) to form DES, which can act as a novel CNTs functionalization agent. The novel adsorbent was characterized using Raman, FTIR, XRD, FESEM, EDX, BET surface area, TGA, TEM and Zeta potential. Response surface methodology was used to optimize the removal conditions for Hg(2+). The optimum removal conditions were found to be pH 5.5, contact time 28 min, and an adsorbent dosage of 5 mg. Freundlich isotherm model described the adsorption isotherm of the novel adsorbent, and the maximum adsorption capacity obtained from the experimental data was 186.97 mg g(-1). Pseudo-second order kinetics describes the adsorption rate order.
    Matched MeSH terms: Nanotubes, Carbon/chemistry*
  2. Adsorption of methyl orange by synthesized and functionalized-CNTs with 3-aminopropyltriethoxysilane loaded TiO2 nanocomposites
    Ahmad A, Razali MH, Mamat M, Mehamod FS, Anuar Mat Amin K
    Chemosphere, 2017 Feb;168:474-482.
    PMID: 27855344 DOI: 10.1016/j.chemosphere.2016.11.028
    This study aims to develop a highly efficient adsorbent material. CNTs are prepared using a chemical vapor deposition method with acetylene and synthesized mesoporous Ni-MCM41 as the carbon source and catalyst, respectively, and are then functionalized using 3-aminopropyltriethoxysilane (APTES) through the co-condensation method and loaded with commercial TiO2. Results of X-ray powder diffraction (XRD), Raman spectra, and Fourier transform infrared spectroscopy (FTIR) confirm that the synthesized CNTs grown are multi-walled carbon nanotubes (MWNTs). Transmission electron microscopy shows good dispersion of TiO2 nanoparticles onto functionalized-CNTs loaded TiO2, with the diameter of a hair-like structure measuring between 3 and 8 nm. The functionalized-CNTs loaded TiO2 are tested as an adsorbent for removal of methyl orange (MO) in aqueous solution, and results show that 94% of MO is removed after 10 min of reaction, and 100% after 30 min. The adsorption kinetic model of functionalized-CNTs loaded TiO2 follows a pseudo-second order with a maximum adsorption capacity of 42.85 mg/g. This study shows that functionalized-CNTs loaded TiO2 has considerable potential as an adsorbent material due to the short adsorption time required to achieve equilibrium.
    Matched MeSH terms: Nanotubes, Carbon/chemistry*
  3. Fulltext A review of drug delivery systems based on nanotechnology and green chemistry: green nanomedicine
    Jahangirian H, Lemraski EG, Webster TJ, Rafiee-Moghaddam R, Abdollahi Y
    Int J Nanomedicine, 2017;12:2957-2978.
    PMID: 28442906 DOI: 10.2147/IJN.S127683
    This review discusses the impact of green and environmentally safe chemistry on the field of nanotechnology-driven drug delivery in a new field termed "green nanomedicine". Studies have shown that among many examples of green nanotechnology-driven drug delivery systems, those receiving the greatest amount of attention include nanometal particles, polymers, and biological materials. Furthermore, green nanodrug delivery systems based on environmentally safe chemical reactions or using natural biomaterials (such as plant extracts and microorganisms) are now producing innovative materials revolutionizing the field. In this review, the use of green chemistry design, synthesis, and application principles and eco-friendly synthesis techniques with low side effects are discussed. The review ends with a description of key future efforts that must ensue for this field to continue to grow.
    Matched MeSH terms: Nanotubes, Carbon/chemistry
  4. Enhanced direct electron transfer of redox protein based on multiporous SnO2 nanofiber-carbon nanotube nanocomposite and its application in biosensing
    Alim S, Kafi AKM, Jose R, Yusoff MM, Vejayan J
    Int J Biol Macromol, 2018 Jul 15;114:1071-1076.
    PMID: 29625222 DOI: 10.1016/j.ijbiomac.2018.03.184
    A novel third generation H2O2 biosensor is fabricated using multiporous SnO2 nanofiber/carbon nanotubes (CNTs) composite as a matrix for the immobilization of redox protein onto glassy carbon electrode. The multiporous nanofiber (MPNFs) of SnO2 is synthesized by electrospinning technique from the tin precursor. This nanofiber shows high surface area and good electrical conductivity. The SnO2 nanofiber/CNT composite increases the efficiency of biomolecule loading due to its high surface area. The morphology of the nanofiber has been evaluated by scanning electron microscopy (SEM). Cyclic Voltammetry and amperometry technique are employed to study and optimize the performance of the fabricated electrode. A direct electron transfer between the protein's redox centre and the glassy carbon electrode is established after fabrication of the electrode. The fabricated electrode shows excellent electrocatalytic reduction to H2O2. The catalysis currents increases linearly to the H2O2 concentration in a wide range of 1.0 10-6-1.4×10-4M and the lowest detection limit was 30nM (S/N=3). Moreover, the biosensor showed a rapid response to H2O2, a good stability and reproducibility.
    Matched MeSH terms: Nanotubes, Carbon/chemistry*
  5. Fulltext Development of Frequency Based Taste Receptors Using Bioinspired Glucose Nanobiosensor
    TermehYousefi A, Tateno K, Bagheri S, Tanaka H
    Sci Rep, 2017 05 09;7(1):1623.
    PMID: 28487527 DOI: 10.1038/s41598-017-01855-5
    A method to fabricate a bioinspired nanobiosensor using electronic-based artificial taste receptors for glucose diagnosis is presented. Fabricated bioinspired glucose nanobiosensor designated based on an artificial taste bud including an amperometric glucose biosensor and taste bud-inspired circuits. In fact, the design of the taste bud-inspired circuits was inspired by the signal-processing mechanism of taste nerves which involves two layers. The first, known as a type II cell, detects the glucose by glucose oxidase and transduces the current signal obtained for the pulse pattern is conducted to the second layer, called type III cell, to induce synchronisation of the neural spiking activity. The oscillation results of fabricated bioinspired glucose nanobiosensor confirmed an increase in the frequency of the output pulse as a function of the glucose concentration. At high glucose concentrations, the bioinspired glucose nanobiosensor showed a pulse train of alternating short and long interpulse intervals. A computational analysis performed to validate the hypothesis, which was successfully reproduced the alternating behaviour of bioinspired glucose our nanobiosensor by increasing the output frequency and alternation of pulse intervals according to the reduction in the resistivity of the biosensor.
    Matched MeSH terms: Nanotubes, Carbon/ultrastructure
  6. Fulltext Fabrication and Characterization of Glucose Biosensors by Using Hydrothermally Grown ZnO Nanorods
    Ridhuan NS, Abdul Razak K, Lockman Z
    Sci Rep, 2018 09 13;8(1):13722.
    PMID: 30213995 DOI: 10.1038/s41598-018-32127-5
    Highly oriented ZnO nanorod (NR) arrays were fabricated on a seeded substrate through a hydrothermal route. The prepared ZnO nanorods were used as an amperometric enzyme electrode, in which glucose oxidase (GOx) was immobilised through physical adsorption. The modified electrode was designated as Nafion/GOx/ZnO NRs/ITO. The morphology and structural properties of the fabricated ZnO nanorods were analysed using field-emission scanning electron microscope and X-ray diffractometer. The electrochemical properties of the fabricated biosensor were studied by cyclic voltammetry and amperometry. Electrolyte pH, electrolyte temperature and enzyme concentration used for immobilisation were the examined parameters influencing enzyme activity and biosensor performance. The immobilised enzyme electrode showed good GOx retention activity. The amount of electroactive GOx was 7.82 × 10-8 mol/cm2, which was relatively higher than previously reported values. The Nafion/GOx/ZnO NRs/ITO electrode also displayed a linear response to glucose ranging from 0.05 mM to 1 mM, with a sensitivity of 48.75 µA/mM and a low Michaelis-Menten constant of 0.34 mM. Thus, the modified electrode can be used as a highly sensitive third-generation glucose biosensor with high resistance against interfering species, such as ascorbic acid, uric acid and L-cysteine. The applicability of the modified electrode was tested using human blood samples. Results were comparable with those obtained using a standard glucometer, indicating the excellent performance of the modified electrode.
    Matched MeSH terms: Nanotubes/chemistry*
  7. Gold-nanorod enhances dielectric voltammetry detection of c-reactive protein: A predictive strategy for cardiac failure
    Letchumanan I, Md Arshad MK, Balakrishnan SR, Gopinath SCB
    Biosens Bioelectron, 2019 Apr 01;130:40-47.
    PMID: 30716591 DOI: 10.1016/j.bios.2019.01.042
    This paper primarily demonstrates the approach to enhance the sensing performance on antigen C-reactive protein (CRP) and anti-CRP antibody binding event. A nanogapped electrode structure with the gap of ~100 nm was modified by the anti-CRP antibody (Probe) to capture the available CRP. In order to increase the amount of antigen to be captured, a gold nanorod with 119 nm in length and 25 nm in width was integrated, to increase the surface area. A comparative study between the existence and non-existence of gold nanorod utilization was evaluated. Analysis of the sensing surface was well-supported by atomic force microscopy, scanning electron microscopy, 3D nano-profilometry, high-power microscopy and UV-Vis spectroscopy. The dielectric voltammetric analysis was carried out from 0 V to 2 V. The sensitivity was calculated based on 3σ and attained as low as 1 pM, which is tremendously low compared to real CRP concentration (119 nM) in human blood serum. The gold nanorod conjugation with antibody has enhanced the sensitivity to 100 folds (10 fM). The specificity of the CRP detection by the proposed strategy was anchored by ELISA and failure in the detection of human blood clotting factor IX by voltammetry. Despite, CRP antigen was further detected in human serum by spiking CRP to run-through the detection with the physiologically relevant samples.
    Matched MeSH terms: Nanotubes/chemistry
  8. Fulltext Feedforward Artificial Neural Network-Based Model for Predicting the Removal of Phenolic Compounds from Water by Using Deep Eutectic Solvent-Functionalized CNTs
    Ibrahim RK, Fiyadh SS, AlSaadi MA, Hin LS, Mohd NS, Ibrahim S, et al.
    Molecules, 2020 Mar 26;25(7).
    PMID: 32225061 DOI: 10.3390/molecules25071511
    In the recent decade, deep eutectic solvents (DESs) have occupied a strategic place in green chemistry research. This paper discusses the application of DESs as functionalization agents for multi-walled carbon nanotubes (CNTs) to produce novel adsorbents for the removal of 2,4-dichlorophenol (2,4-DCP) from aqueous solution. Also, it focuses on the application of the feedforward backpropagation neural network (FBPNN) technique to predict the adsorption capacity of DES-functionalized CNTs. The optimum adsorption conditions that are required for the maximum removal of 2,4-DCP were determined by studying the impact of the operational parameters (i.e., the solution pH, adsorbent dosage, and contact time) on the adsorption capacity of the produced adsorbents. Two kinetic models were applied to describe the adsorption rate and mechanism. Based on the correlation coefficient (R2) value, the adsorption kinetic data were well defined by the pseudo second-order model. The precision and efficiency of the FBPNN model was approved by calculating four statistical indicators, with the smallest value of the mean square error being 5.01 × 10-5. Moreover, further accuracy checking was implemented through the sensitivity study of the experimental parameters. The competence of the model for prediction of 2,4-DCP removal was confirmed with an R2 of 0.99.
    Matched MeSH terms: Nanotubes, Carbon/chemistry*
  9. Fabrication and dialysis performance of functionalized multiwall carbon nanotubes integrated cellulose acetate/poly(vinylpyrrolidone) membranes
    Ashraf MA, Islam A, Butt MA, Hussain T, Khan RU, Bashir S, et al.
    Int J Biol Macromol, 2021 Nov 30;191:872-880.
    PMID: 34571131 DOI: 10.1016/j.ijbiomac.2021.09.131
    Mixed matrix membranes (MMMs) of cellulose acetate/poly(vinylpyrrolidone) (CA/PVP) infused with acid functionalized multiwall carbon nanotubes (f-MWCNTs) were fabricated by an immersion phase separation technique for hemodialysis application. Membranes were characterized using FTIR, water uptake, contact angle, TGA, DMA and SEM analysis. The FTIR was used to confirm the bonding interaction between CA/PVP membrane matrix and f-MWCNTs. Upon addition of f-MWCNTs, TGA thermograms and glass transition temperature indicated improved thermal stability of MMMs. The surface morphological analysis demonstrated revealed uniform distribution of f-MWCNTs and asymmetric membrane structure. The water uptake and contact angle confirmed that hydrophilicity was increased after incorporation of f-MWCNTs. The membranes demonstrated enhancement in water permeate flux, bovine serum albumin (BSA) rejection with the infusion of f-MWCNTs; whereas BSA based anti-fouling analysis using flux recovery ratio test shown up to 8.4% improvement. The urea and creatinine clearance performance of MMMs were evaluated by dialysis experiment. It has been found that f-MWCNTs integrated membranes demonstrated the higher urea and creatinine clearance with increase of 12.6% and 10.5% in comparison to the neat CA/PVP membrane. Thus, the prepared CA/PVP membranes embedded with f-MWCNTs can be employed for wide range of dialysis applications.
    Matched MeSH terms: Nanotubes, Carbon/chemistry*
  10. The modelling of lead removal from water by deep eutectic solvents functionalized CNTs: artificial neural network (ANN) approach
    Fiyadh SS, AlSaadi MA, AlOmar MK, Fayaed SS, Hama AR, Bee S, et al.
    Water Sci Technol, 2017 Nov;76(9-10):2413-2426.
    PMID: 29144299 DOI: 10.2166/wst.2017.393
    The main challenge in the lead removal simulation is the behaviour of non-linearity relationships between the process parameters. The conventional modelling technique usually deals with this problem by a linear method. The substitute modelling technique is an artificial neural network (ANN) system, and it is selected to reflect the non-linearity in the interaction among the variables in the function. Herein, synthesized deep eutectic solvents were used as a functionalized agent with carbon nanotubes as adsorbents of Pb2+. Different parameters were used in the adsorption study including pH (2.7 to 7), adsorbent dosage (5 to 20 mg), contact time (3 to 900 min) and Pb2+ initial concentration (3 to 60 mg/l). The number of experimental trials to feed and train the system was 158 runs conveyed in laboratory scale. Two ANN types were designed in this work, the feed-forward back-propagation and layer recurrent; both methods are compared based on their predictive proficiency in terms of the mean square error (MSE), root mean square error, relative root mean square error, mean absolute percentage error and determination coefficient (R2) based on the testing dataset. The ANN model of lead removal was subjected to accuracy determination and the results showed R2 of 0.9956 with MSE of 1.66 × 10-4. The maximum relative error is 14.93% for the feed-forward back-propagation neural network model.
    Matched MeSH terms: Nanotubes, Carbon/chemistry*
  11. Immobilization of cross-linked tannase enzyme on multiwalled carbon nanotubes and its catalytic behavior
    Ong CB, Annuar MSM
    Prep Biochem Biotechnol, 2018 Feb 07;48(2):181-187.
    PMID: 29341838 DOI: 10.1080/10826068.2018.1425707
    Immobilization of cross-linked tannase on pristine multiwalled carbon nanotubes (MWCNT) was successfully performed. Cross-linking of tannase molecules was made through glutaraldehyde. The immobilized tannase exhibited significantly improved pH, thermal, and recycling stability. The optimal pH for both free and immobilized tannase was observed at pH 5.0 with optimal operating temperature at 30°C. Moreover, immobilized enzyme retained greater biocatalytic activities upon 10 repeated uses compared to free enzyme in solution. Immobilization of tannase was accomplished by strong hydrophobic interaction most likely between hydrophobic amino acid moieties of the glutaraldehyde-cross-linked tannase to the MWCNT.
    Matched MeSH terms: Nanotubes, Carbon/chemistry*
  12. A novel nanocomposite of aminated silica nanotube (MWCNT/Si/NH2) and its potential on adsorption of nitrite
    Altowayti WAH, Allozy HGA, Shahir S, Goh PS, Yunus MAM
    Environ Sci Pollut Res Int, 2019 Oct;26(28):28737-28748.
    PMID: 31376124 DOI: 10.1007/s11356-019-06059-0
    Several parts of the world have been facing the problem of nitrite and nitrate contamination in ground and surface water. The acute toxicity of nitrite has been shown to be 10-fold higher than that of nitrate. In the present study, aminated silica carbon nanotube (ASCNT) was synthesised and tested for nitrite removal. The synergistic effects rendered by both amine and silica in ASCNT have significantly improved the nitrite removal efficiency. The IEP increased from 2.91 for pristine carbon nanotube (CNT) to 8.15 for ASCNT, and the surface area also increased from 178.86 to 548.21 m2 g-1. These properties have promoted ASCNT a novel adsorbent to remove nitrite. At optimum conditions of 700 ppm of nitrite concentration at pH 7 and 5 h of contact with 15 mg of adsorbent, the ASCNT achieved the maximal loading capacity of 396 mg/g (85% nitrite removal). The removal data of nitrite onto ASCNT fitted the Langmuir isotherm model better than the Freundlich isotherm model with the highest regression value of 0.98415, and also, the nonlinear analysis of kinetics data showed that the removal of nitrite followed pseudo-second-order kinetic. The positive values of both ΔS° and ΔH° suggested an endothermic reaction and an increase in randomness at the solid-liquid interface. The negative ΔG° values indicated a spontaneous adsorption process. The ASCNT was characterised using FESEM-EDX and FTIR, and the results obtained confirmed the removal of nitrite. Based on the findings, ASCNT can be considered as a novel and promising candidate for the removal of nitrite ions from wastewater.
    Matched MeSH terms: Nanotubes, Carbon/chemistry*
  13. Fulltext Gold Nanorod Integrated Electrochemical Sensing for Hyperglycaemia on Interdigitated Electrode
    Zheng S, Zhang H, Lakshmipriya T, Gopinath SCB, Yang N
    Biomed Res Int, 2019;2019:9726967.
    PMID: 31380444 DOI: 10.1155/2019/9726967
    Gestational diabetes (hyperglycaemia) is an elevated blood sugar level diagnosed during the period of pregnancy and affects the baby's health. Hyperglycaemia has been found within the gestational weeks between 24 and 28, and the foetus has also the possibility of getting out prior to this test frame; it causes excessive birth weight, early birth, low-blood sugar level, respiratory distress syndrome, and type-2 diabetes to the mother. It creates a mandatory situation to identify the hyperglycaemia at least during the pregnancy weeks from 18 to 20. Further, a continuous monitoring of the level of glucose is necessary for the proper delivery. In this work, a method is introduced for glucose detection at 0.06 mg/mL, assisted by gold nanorod (GNR)-conjugated glucose oxidase (GOx) on interdigitated electrode sensor. In the absence of GNR, GOx shows the limit of glucose detection to be 0.25 mg/mL. Moreover, with GOx-GNR the reactions of all the glucose concentrations have recorded higher levels of the current from the baseline. With the specificity analysis, it was found that the glucose only reacts with GOx-GNR and discriminates other sugars efficiently. This method of detection is useful to diagnose and continuously monitor the glucose level during the pregnancy period.
    Matched MeSH terms: Nanotubes/chemistry*
  14. Fulltext Effect of solution pH and adsorbent concentration on the sensing parameters of TGN-based electrochemical sensor
    Rahmani M, Ghafoorifard H, Afrang S, Ahmadi MT, Rahmani K, Ismail R
    IET Nanobiotechnol, 2019 Aug;13(6):584-592.
    PMID: 31432790 DOI: 10.1049/iet-nbt.2018.5288
    The response of trilayer graphene nanoribbon (TGN)-based ion-sensitive field-effect transistor (ISFET) to different pH solutions and adsorption effect on the sensing parameters are analytically studied in this research. The authors propose a TGN-based sensor to electrochemically detect pH. To this end, absorption effect on the sensing area in the form of carrier concentration, carrier velocity, and conductance variations are investigated. Also, the caused electrical response on TGN as a detection element is analytically proposed, in which significant current decrease of the sensor is observed after exposure to high pH values. In order to verify the accuracy of the model, it is compared with recent reports on pH sensors. The TGN-based pH sensor exposes higher current compared to that of carbon nanotube (CNT) counterpart for analogous ambient conditions. While, the comparative results demonstrate that the conductance of proposed model is lower than that of monolayer graphene-counterpart for equivalent pH values. The results confirm that the conductance of the sensor is decreased and Vg-min is obviously right-shifted by increasing value of pH. The authors demonstrate that although there is not the experimental evidence reported in the part of literature for TGN sensor, but the model can assist in comprehending experiments involving nanoscale pH sensors.
    Matched MeSH terms: Nanotubes, Carbon/chemistry*
  15. In vitro and in vivo study of hazardous effects of Ag nanoparticles and Arginine-treated multi walled carbon nanotubes on blood cells: application in hemodialysis membranes
    Zare-Zardini H, Amiri A, Shanbedi M, Taheri-Kafrani A, Kazi SN, Chew BT, et al.
    J Biomed Mater Res A, 2015 Sep;103(9):2959-65.
    PMID: 25690431 DOI: 10.1002/jbm.a.35425
    One of the novel applications of the nanostructures is the modification and development of membranes for hemocompatibility of hemodialysis. The toxicity and hemocompatibility of Ag nanoparticles and arginine-treated multiwalled carbon nanotubes (MWNT-Arg) and possibility of their application in membrane technology are investigated here. MWNT-Arg is prepared by amidation reactions, followed by characterization by FTIR spectroscopy, Raman spectroscopy, and thermogravimetric analysis. The results showed a good hemocompatibility and the hemolytic rates in the presence of both MWNT-Arg and Ag nanoparticles. The hemolytic rate of Ag nanoparticles was lower than that of MWNT-Arg. In vivo study revealed that Ag nanoparticle and MWNT-Arg decreased Hematocrit and mean number of red blood cells (RBC) statistically at concentration of 100 µg mL(-1) . The mean decrease of RBC and Hematocrit for Ag nanoparticles (18% for Hematocrit and 5.8 × 1,000,000/µL) was more than MWNT-Arg (20% for Hematocrit and 6 × 1000000/µL). In addition, MWNT-Arg and Ag nanoparticles had a direct influence on the White Blood Cell (WBC) drop. Regarding both nanostructures, although the number of WBC increased in initial concentration, it decreased significantly at the concentration of 100 µg mL(-1) . It is worth mentioning that the toxicity of Ag nanoparticle on WBC was higher than that of MWNT-Arg. Because of potent antimicrobial activity and relative hemocompatibility, MWNT-Arg could be considered as a new candidate for biomedical applications in the future especially for hemodialysis membranes.
    Matched MeSH terms: Nanotubes, Carbon/toxicity*; Nanotubes, Carbon/chemistry
  16. Effects of anodizing parameters and heat treatment on nanotopographical features, bioactivity, and cell culture response of additively manufactured porous titanium
    Amin Yavari S, Chai YC, Böttger AJ, Wauthle R, Schrooten J, Weinans H, et al.
    Mater Sci Eng C Mater Biol Appl, 2015 Jun;51:132-8.
    PMID: 25842117 DOI: 10.1016/j.msec.2015.02.050
    Anodizing could be used for bio-functionalization of the surfaces of titanium alloys. In this study, we use anodizing for creating nanotubes on the surface of porous titanium alloy bone substitutes manufactured using selective laser melting. Different sets of anodizing parameters (voltage: 10 or 20V anodizing time: 30min to 3h) are used for anodizing porous titanium structures that were later heat treated at 500°C. The nanotopographical features are examined using electron microscopy while the bioactivity of anodized surfaces is measured using immersion tests in the simulated body fluid (SBF). Moreover, the effects of anodizing and heat treatment on the performance of one representative anodized porous titanium structures are evaluated using in vitro cell culture assays using human periosteum-derived cells (hPDCs). It has been shown that while anodizing with different anodizing parameters results in very different nanotopographical features, i.e. nanotubes in the range of 20 to 55nm, anodized surfaces have limited apatite-forming ability regardless of the applied anodizing parameters. The results of in vitro cell culture show that both anodizing, and thus generation of regular nanotopographical feature, and heat treatment improve the cell culture response of porous titanium. In particular, cell proliferation measured using metabolic activity and DNA content was improved for anodized and heat treated as well as for anodized but not heat-treated specimens. Heat treatment additionally improved the cell attachment of porous titanium surfaces and upregulated expression of osteogenic markers. Anodized but not heat-treated specimens showed some limited signs of upregulated expression of osteogenic markers. In conclusion, while varying the anodizing parameters creates different nanotube structure, it does not improve apatite-forming ability of porous titanium. However, both anodizing and heat treatment at 500°C improve the cell culture response of porous titanium.
    Matched MeSH terms: Nanotubes/ultrastructure; Nanotubes/chemistry*
  17. Enhanced amperometric detection of paracetamol by immobilized cobalt ion on functionalized MWCNTs - Chitosan thin film
    Akhter S, Basirun WJ, Alias Y, Johan MR, Bagheri S, Shalauddin M, et al.
    Anal Biochem, 2018 06 15;551:29-36.
    PMID: 29753720 DOI: 10.1016/j.ab.2018.05.004
    In the present study, a nanocomposite of f-MWCNTs-chitosan-Co was prepared by the immobilization of Co(II) on f-MWCNTs-chitosan by a self-assembly method and used for the quantitative determination of paracetamol (PR). The composite was characterized by field emission scanning electron microscopy (FESEM) and energy dispersive x-ray analysis (EDX). The electroactivity of cobalt immobilized on f-MWCNTs-chitosan was assessed during the electro-oxidation of paracetamol. The prepared GCE modified f-MWCNTs/CTS-Co showed strong electrocatalytic activity towards the oxidation of PR. The electrochemical performances were investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV). Under favorable experimental conditions, differential pulse voltammetry showed a linear dynamic range between 0.1 and 400 μmol L-1 with a detection limit of 0.01 μmol L-1 for the PR solution. The fabricated sensor exhibited significant selectivity towards PR detection. The fabricated sensor was successfully applied for the determination of PR in commercial tablets and human serum sample.
    Matched MeSH terms: Nanotubes, Carbon/ultrastructure; Nanotubes, Carbon/chemistry
  18. Fulltext Early-stage cervical cancer diagnosis based on an ultra-sensitive electrochemical DNA nanobiosensor for HPV-18 detection in real samples
    Mahmoodi P, Rezayi M, Rasouli E, Avan A, Gholami M, Ghayour Mobarhan M, et al.
    J Nanobiotechnology, 2020 Jan 13;18(1):11.
    PMID: 31931815 DOI: 10.1186/s12951-020-0577-9
    BACKGROUND: In several years ago, infection with human papillomaviruses (HPVs), have been prevalent in the worlds especially HPV type 18, can lead to cervical cancer. Therefore, rapid, accurate, and early diagnosis of HPV for successful treatment is essential. The present study describes the development of a selective and sensitive electrochemical biosensor base on DNA, for early detection of HPV-18. For this purpose, a nanocomposite of reduced graphene oxide (rGO) and multiwalled carbon nanotubes (MWCNTs) were electrodeposited on a screen-printed carbon electrode (SPCE). Then, Au nanoparticles (AuNPs) were dropped on a modified SPCE. Subsequently, single strand DNA (ssDNA) probe was immobilized on the modified electrode. The link attached between AuNPs and probe ssDNA provided by L-cysteine via functionalizing AuNPs (Cys-AuNPs). The differential pulse voltammetry (DPV) assay was also used to electrochemical measurement. The measurement was based on the oxidation signals of anthraquninone-2-sulfonic acid monohydrate sodium salt (AQMS) before and after hybridization between the probe and target DNA.

    RESULTS: The calibration curve showed a linear range between 0.01 fM to 0.01 nM with a limit of detection 0.05 fM. The results showed that the optimum concentration for DNA probe was 5 µM. The good performance of the proposed biosensor was achieved through hybridization of DNA probe-modified SPCE with extracted DNA from clinical samples.

    CONCLUSIONS: According to the investigated results, this biosensor can be introduced as a proprietary, accurate, sensitive, and rapid diagnostic method of HPV 18 in the polymerase chain reaction (PCR) of real samples.

    Matched MeSH terms: Nanotubes, Carbon/ultrastructure; Nanotubes, Carbon/chemistry*
  19. Carbonaceous nanomaterials immobilised mixed matrix membrane microextraction for the determination of polycyclic aromatic hydrocarbons in sewage pond water samples
    Mukhtar NH, See HH
    Anal Chim Acta, 2016 08 10;931:57-63.
    PMID: 27282751 DOI: 10.1016/j.aca.2016.04.032
    In this study, the potential for carbonaceous nanomaterials to be used as adsorbents for the mixed matrix membrane (MMM) microextraction and preconcentration of organic pollutants was demonstrated. For this method, multiwall carbon nanotubes (MWCNT) and single layer graphene (SLG) nanoparticles were individually incorporated through dispersion in a cellulose triacetate (CTA) polymer matrix to form a MWCNT-MMM and SLG-MMM, respectively. The prepared membranes were evaluated for the extraction of selected polycyclic aromatic hydrocarbons (PAHs) present in sewage pond water samples. The extraction was performed by dipping a small piece of membrane (7 mm × 7 mm) in a stirred 7.5 mL sample solution to initiate the analyte adsorption. This step was followed by an analyte desorption into 60 μL of methanol prior to high performance liquid chromatography (HPLC) analysis. When the optimum SLG-MMM microextraction technique was applied to spiked sewage pond water samples, the detection limit of the method for the PAHs were in the range of 0.02-0.09 ng/mL, with relative standard deviations of between 1.4% and 7.8%. Enrichment factors of 54-100 were achieved with relative recoveries of 99%-101%. A comparison was also made between the proposed approach and standard solid phase extraction using polymeric bonded octadecyl (C18) cartridges.
    Matched MeSH terms: Nanotubes, Carbon
  20. Fulltext Properties and Applications of Polyvinyl Alcohol, Halloysite Nanotubes and Their Nanocomposites
    Gaaz TS, Sulong AB, Akhtar MN, Kadhum AA, Mohamad AB, Al-Amiery AA
    Molecules, 2015;20(12):22833-47.
    PMID: 26703542 DOI: 10.3390/molecules201219884
    The aim of this review was to analyze/investigate the synthesis, properties, and applications of polyvinyl alcohol-halloysite nanotubes (PVA-HNT), and their nanocomposites. Different polymers with versatile properties are attractive because of their introduction and potential uses in many fields. Synthetic polymers, such as PVA, natural polymers like alginate, starch, chitosan, or any material with these components have prominent status as important and degradable materials with biocompatibility properties. These materials have been developed in the 1980s and are remarkable because of their recyclability and consideration of the natural continuation of their physical and chemical properties. The fabrication of PVA-HNT nanocomposites can be a potential way to address some of PVA's limitations. Such nanocomposites have excellent mechanical properties and thermal stability. PVA-HNT nanocomposites have been reported earlier, but without proper HNT individualization and PVA modifications. The properties of PVA-HNT for medicinal and biomedical use are attracting an increasing amount of attention for medical applications, such as wound dressings, drug delivery, targeted-tissue transportation systems, and soft biomaterial implants. The demand for alternative polymeric medical devices has also increased substantially around the world. This paper reviews individualized HNT addition along with crosslinking of PVA for various biomedical applications that have been previously reported in literature, thereby showing the attainability, modification of characteristics, and goals underlying the blending process with PVA.
    Matched MeSH terms: Nanotubes
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