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Sensing of Environmentally Hazardous Chemicals by Carbon Nanotubes
Published in Soney C. George, Jacob Philip, Ann Rose Abraham, A. K. Haghi, Carbon Nanotubes for Energy and Environmental Applications, 2023
Sijo Francis, Remya Vijayan, Ebey P. Koshy, Beena Mathew
Dyes are colored chemicals and are non-biodegradable in nature due to presence of aromatic chains and high molecular weight. Single-walled and multiwalled carbon nanotubes help the efficient removal of various organic dyes with the assistance of different technologies. The incorporation of functional groups with CNTs would enhance the adsorption capability of dyes. Congo red dye can be removed within 60 min by pseudo-second-order adsorption kinetics.24 MWCNT functionalized by cysteamine composite with carboxyl group and thiol groups is used for the removal of Amido black 10B dye.25 MWCNT acts as catalyst for the decomposition of Acid Red 14 in the presence of light. The contaminant removal by nanotechnology uses mainly the mechanism called advanced oxidation process. Adsorption on CNTs and removal of pollutants using nanostructured membranes based on CNTs are quite common.26 The manganese-based catalysts are highly selective in the reduction of NO with NH3. Green synthesized multilayered Fe2O3@MnOx@CNTs have MnOx@CNTs core-shell structure.27
Benefits of Nanomaterials-Based Biosensors
Published in Jyoti Ranjan Rout, Rout George Kerry, Abinash Dutta, Biotechnological Advances for Microbiology, Molecular Biology, and Nanotechnology, 2022
Sourav Mishra, Rohit Kumar Singh, Uday Suryakanta, Bijayananda Panigrahi, Dindyal Mandal
Li et al. and Cao et al. have established a heparin detection assay by using the cysteamine-capped gold nanoparticle with the mechanism of electrostatic interactions (Li et al., 2010; Cao et al., 2011; Gemene et al., 2010). Cysteamine-capped gold nanoparticles are positively charged as the amine of cycteamine is protonated at pH 3.6 and that off heparin is negatively charged. Therefore, this positively charged gold nanoparticle exhibits electrostatic interaction during incubation with negatively charged heparin. Thus, in the presence of different concentrations of heparin, the absorption of AuNPs at 520 nm gradually decreases, whereas, absorption at 670 nm gradually increases with a color change from red to blue. For the mechanistic aspects, negative charge citrate-capped gold nanoparticles have been incubated with heparin, which results in no color change or spectral change. The limit of detection of heparin by these cysteamine-capped gold nanoparticles was found to be 0.03 mg mL−1.
Gold Nanoparticles Modification and Aggregation: Applications from Bio- and Chemosensing to Drug Development
Published in Volodymyr I. Chegel, Andrii M. Lopatynskyi, Molecular Plasmonics, 2020
Volodymyr I. Chegel, Andrii M. Lopatynskyi
To study the features of the optical response of the LSPR sensor operating in the mode of aggregation of nanoparticles, measurements of light extinction spectra of colloidal solutions of AuNPs were performed upon addition of aqueous solutions of thiourea, cysteamine hydrochloride, 6-mercapto-1-hexanol, tris(hydroxymethyl) aminomethane, and ethanol amine. Changes in the extinction spectra occurring after the addition of analyte solutions (Fig. 8.6) indicate a gradual loss of colloidal stability of AuNPs solution under the action of molecules of analytes. The peculiarities of the optical response, which reflect the AuNPs aggregation process, were discovered to be dependent on the structure and charge of the analyte molecules. Thus, the presence of sulfur atoms in the molecules of an analyte, which allows these compounds to covalently bind to gold atoms on the surface of nanoparticles, leads to the effective substitution of citrate ions that stabilize nanoparticles in a colloidal solution. If the charge of the analyte molecule is positive (for example, due to the presence of ionized amino groups, as in the molecules of thiourea and the cysteamine hydrochloride), then rapid aggregation and precipitation of AuNPs at small concentrations of the analyte (several μmol/L) are observed (Fig. 8.6a, b). If the sulfur compound has neutral functional groups (e.g., 6-mercapto-1-hexanol), then aggregation of AuNPs with further limited stability of the colloidal solution is evidenced (Fig. 8.6c).
An efficient one-pot synthesis of tetrahydrothiazolo[3,2-a]quinolin-6-one derivatives
Published in Journal of Sulfur Chemistry, 2018
Mohammad Bayat, Fahimeh Sadat Hosseini, Shima Nasri
Based on these results, a plausible mechanism is shown in Scheme 2. Initially, the reaction between cysteamine hydrochloride 1 and 1,1-bis(methylthio)-2-nitroethene 2 in the presence of Et3N affords 2-(nitromethylene)thiazolidine 6 [28–30]. While the condensation of dimedone 4 with aromatic aldehyde 3 furnishes adduct 7. Then, the 2-(nitromethylene)thiazolidine 6 and adduct 7 undergo a Michael addition to give intermediate 8, which undergoes successive imine–enamine tautomerization, followed by nucleophilic addition of the secondary amino group to the carbonyl group and then cyclization, leading to the formation of 5.
Highly recyclable cysteamine-modified acid-resistant MOFs for enhancing Hg (II) removal from water
Published in Environmental Technology, 2020
Fengtai Liu, Wenjing Xiong, Xinrui Feng, Ge Cheng, Lei Shi, Dawei Chen, Yibo Zhang
Since in many cases mercury ions from waste water are present in acidic aqueous solutions, in addition, the elution of mercury ions from adsorbents also requires an acidic environment. The adsorbents that possess an acidic stability in aqueous solutions are desired. After all these considerations, UiO-66-COOH and MIL-101(Cr) were selected as a kind of potential materials due to its outstanding acidic stability in water [31–33]. Moreover, UiO-66-COOH possesses free carboxylic groups that can be modified. In this work, cysteamine was introduced and modified into the two types of acid-resistant MOFs materials. UiO-66-SH samples were synthesized via condensation reaction between cysteamine and carboxyl groups using carbodiimide coupling. In the structure of MIL-101(Cr), the coordinatively unsaturated metal sites (CUSs) can be seen as Lewis acid sites usable for the surface functionalization with organic molecules [34]. To incorporate thiol groups into MIL-101, cysteamine was selected where the amino unit will be coordinated to the CUSs of the framework. These two types of adsorbents were sufficiently characterized by FTIR, XPS, XRD, and N2 adsorption isotherms respectively. The adsorption of Hg (II) onto the pristine MOFs and thiol-functionalized MOFs materials as a function of solution pH and initial Hg (II) concentration were studied in detail as well. We also conducted desorption studies on UiO-66-SH and MIL-101-SH samples in order to investigate their performances as the properly recycled adsorbents. Finally, the release of Zr4+ or Cr3+ from the spent adsorbents under acidic conditions was also investigated and the concentration of Zr4+ and Cr3+ in solution was determined by ICP in detail.
Optical control of cell differentiation on synthetic collagen-like scaffolds
Published in Journal of Biomaterials Science, Polymer Edition, 2019
Mime Kobayashi, Ryosuke Honda, Tsuyoshi Ando, Masao Tanihara
For the photo reaction, first, poly(Pro-Hyp-Gly)-graft-4-pentenoate film was washed with PBS to moisten the film. In a 1.5 mL tube, 12.2 mg (107 μmol) of cysteamine hydrochloride was prepared. Just after dissolving the chemical with 200 μL 5.35 μM eosin Y solution, the solution mixture was poured onto the film and 488 nm argon laser irradiation (1 to 20 mW/cm2 intensity for 1 to 5 min) was applied to 200 μm × 200 μm squares using a LSM710 confocal laser scanning microscope (CLSM, Carl Zeiss, Oberkochen, Germany). The film was washed with PBS, Milli-Q H2O, methanol, and dried before proceeding to the next experiments.