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Conducting Polymers for Gene Delivery
Published in Ram K. Gupta, Conducting Polymers, 2022
Aykut Arif Topcu, Erdoğan Özgür, Adil Denizli
Chemiluminescence (CL) is a detection method for DNA hybridization and measures the specific luminescence activity of the labels linked to the DNA probe for the detection of the target DNA [48]. Various labels such as enzymes, metal nanoparticles, and the conjugated polymers are utilized in DNA hybridization studies [48]. Cationic PY derivatives are used as optical probes due to the light-harvesting property and show optical amplification via FRET. Hence, the researchers synthesized poly[(9,9-di(3,3-N,N-trimethyl ammonium)propylfluorenyl-2,7,-diyl)-alt-co-(1,4-phenylene)] dibromide (PFP+) and aimed to develop CL-based detection method for DNA hybridization thanks to the enhancement effect of PFP+ on luminol-H2O2 CL system. Additionally, the enhancement effect of PFP+ on luminol-H2O2 can be controlled by adding DNAs, and the electrostatic interactions between DNA and PFP+ result in decreasing the affinity of PFP+ to luminol dianion and peroxide ion. Therefore, the hybridization of probe DNA and target DNA is investigated by the enhancement effect of PFP+. The electrostatic interactions between PFP+ and luminol dianion and the peroxide ion were responsible for enhancing CL intensity. The binding affinity of PFP+ toward dsDNA was higher than ssDNA and the lengths of the base could influence DNA hybridization. The increase of the base lengths resulted in decreasing CL intensity.
pH Measurement
Published in John G. Webster, Halit Eren, Measurement, Instrumentation, and Sensors Handbook, 2017
Norman F. Sheppard, Anthony Guiseppi-Elie
Fluorescent indicator dyes absorb light of a particular color (or wavelength) and reemit some of the absorbed energy as light of a different color. Absorption of light by the indicator promotes the molecule from the ground state energy, Eg, to a higher energy state, E1. Subsequent processes such as molecular collisions lead to a transition to a lower energy excited state, E2. The molecule can then emit a photon of energy E2−Eg, resulting in the return of the molecule to the ground state from this intermediate state. The emitted light is at a longer wavelength than the exciting wavelength, and the difference is known as the Stokes shift. In principle, a fluorescence measurement is more sensitive than an absorption measurement because the only light measured by the detector originates from fluorescing molecules. Table 59.4 lists a number of common fluorescent pH indicators used for measurement of pH in the physiological range. Fluorescein is widely used because the absorption maximum at 490 nm of the fluorescent dianion is readily excited by the 488 nm emission of argon ion lasers.
Electrodeposited Functional Platforms for Gas Sensing Applications
Published in Ankur Gupta, Mahesh Kumar, Rajeev Kumar Singh, Shantanu Bhattacharya, Gas Sensors, 2023
Hrudaya Jyoti Biswal, Pandu R. Vundavilli, Ankur Gupta
Conducting polymers, useful for gas sensing, is the result of the addition of a donor or acceptor molecule to the polymer, termed as ‘doping’. The main chain of pure polymers contains alternative single and double bonds. The doping process of the polymer chain starts with the formation of a cation or anion radical known as soliton or polaron (equation 5.12). The transfer of the second electron may happen with the formation of a dication or dianion known as bipolaron (equation 5.13). Alternatively, intermixing of the charged and neutral segments of the polymer when possible (equation 5.14).
Efficient preparation of phosphazene chitosan derivatives and its applications for the adsorption of molybdenum from spent hydrodesulfurization catalyst
Published in Journal of Dispersion Science and Technology, 2022
Hala. A. Ibrahium, Bahig M. Atia, Nasser. S. Awwad, A. A. Nayl, Hend A. Radwan, Mohamed A. Gado
According to the surface chemistry concept, the solid adsorbent creates an electric double layer with the adsorbate via the electrostatic attraction,[67] which increases the strength of the coexisting ions and compresses double layer thickness.[68] Furthermore, the competition adsorption between these acid anion and Molbdenum anion was thought to be connected to the anion's chemical structure, valence, hydration state, and other factors. The presence of SO42– in solution had a more noticeable influence on the adsorption of Mo (VI). Cl–, a monovalent anion, has lower ion energy and electrostatic adsorption than dianion or trivalent anion. According to the similar reason, SO42– had a stronger competitiveness for binding positively charged surface which weakened the adsorption for Mo(VI).[69,70]
Synthesis, crystal structure, thermal studies and antimicrobial activity of a new chelate complex of copper(II) succinate with N,N,N′,N′-tetramethylethylenediamine
Published in Journal of Coordination Chemistry, 2020
Syeda Shahzadi Batool, Syeda Rubina Gilani, Syeda Sakina Zainab, Muhammad Nawaz Tahir, William T. A. Harrison, Muhammad Salman Haider, Quratulain Syed, Sania Mazhar, Muhammad Shoaib
Complex 1 crystallizes in monoclinic system with the space group, P21/n. The X-ray crystal structure of the molecular unit of [Cu(tmen)(succ)]n·4nH2O (1) which is a coordination polymer is given together with atomic labeling in Figure 3 and selected bond lengths and angles are presented in Table 3. Single-crystal X-ray analysis discloses that the asymmetric unit of 1 consists of a Cu2+ ion, A chelating tmen ligand, a bridging succinate (C4H4O42–) dianion along with four water molecules of crystallization (Figure 3). The backbone of the C4H4O42– anion has a gauche conformation [C1–C2–C3–C4 = 65.3(3)°] and the dihedral angle between the C1/O1/O2 and C4/O3/O4 carboxylate groups is 76.4(2)°. The carboxylate C1–O1 [1.241(3) Å] and C1–O2 [1.283(3) Å] bond lengths are distinctly different, perhaps because O2 forms a shorter and presumably stronger bond to the copper ion (vide infra) and the same situation applies to the C4 − O3 [1.279(3) Å] and C4–O4 [1.243(3) Å] bond lengths.
The role of guaiacyl moiety in free radical scavenging by 3,5-dihydroxy-4-methoxybenzyl alcohol: thermodynamics of 3H+/3e− mechanisms
Published in Molecular Physics, 2019
Ana Amić, Zoran Marković, Jasmina M. Dimitrić Marković, Dejan Milenković, Bono Lučić
The tSPLET mechanism proceeds in six steps. The first two steps are deprotonation of phenolic OH groups giving phenoxide dianion ((−O)Ar(OCH3)(O−)), Equations (4) and (5). The third step is electron transfer from phenoxide dianion producing radical anion ((−O)Ar(OCH3)(O•)), Equation (6). The fourth step is deprotonation of OCH3 group resulting in radical dianion ((−O)Ar(OCH2−)(O•)), Equation (7), which by electron transfer in the fifth step gives phenoxide anion of HMBD ((−O)Ar(OCH2O)), Equation (8). Finally, electron transfer from (−O)Ar(OCH2O) gives phenoxyl radical of HMBD, Equation (9).