Control of surface states of titanium dioxide nanoparticles using <em>2</em>-(<em>3,4</em>-<em>dihydroxyphenyl</em>)<em>ethylamine</em> (dopamine) and <em>3,4</em>-dihydrophenylacetic acid, which act as ligands to the undercoordinated surface sites (carrier traps), is demonstrated by electrochemical techniques. The deepest traps were found to be most reactive and are selectively removed by the addition of the ligands which enhances the kinetics of electron accumulation in the film. Furthermore, a shift in the Fermi level to more positive potentials was detected for electrodes modified with the negatively charged ligand (<em>3,4</em>-dihydrophenylacetic acid) compared to that of electrodes modified with the positively charged ligand (dopamine). The presence of the negative charge on the ligand also contributed to the underpotential of hydrogen evolution on <em>3,4</em>-dihydrophenylacetic acid-modified electrodes.

The study describes the design and synthesis of an implantable smart magnetic nanofiber device for endoscopic hyperthermia treatment and tumor-triggered controlled drug release. This device is achieved using a two-component smart nanofiber matrix from monodisperse iron oxide nanoparticles (IONPs) as well as bortezomib (BTZ), a chemotherapeutic drug. The IONP-incorporated nanofiber matrix was developed by electrospinning a biocompatible and bioresorbable polymer, poly (d,l-lactide-co-glycolide) (PLGA), and tumor-triggered anticancer drug delivery is realized by exploiting mussel-inspired surface functionalization using <em>2</em>-(<em>3,4</em>-<em>dihydroxyphenyl</em>)<em>ethylamine</em> (dopamine) to conjugate the borate-containing BTZ anticancer drug through a catechol metal binding in a pH-sensitive manner. Thus, an implantable smart magnetic nanofiber device can be exploited to both apply hyperthermia with an alternating magnetic field (AMF) and to achieve cancer cell-specific drug release to enable synergistic cancer therapy. These results confirm that the BTZ-loaded mussel-inspired magnetic nanofiber matrix (BTZ-MMNF) is highly beneficial not only due to the higher therapeutic efficacy and low toxicity towards normal cells but also, as a result of the availability of magnetic nanoparticles for repeated hyperthermia application and tumor-triggered controlled drug release.

UNASSIGNED

The current work report on the design and development of a smart nanoplatform responsive to a magnetic field to administer both hyperthermia and pH-dependent anticancer drug release for the synergistic anticancer treatment. The iron oxide nanoparticles (IONPs) incorporated nanofiber matrix was developed by electrospinning a biocompatible polymer, poly (d,l-lactide-co-glycolide) (PLGA), and tumor-triggered anticancer drug delivery is realized by surface functionalization using <em>2</em>-(<em>3,4</em>-<em>dihydroxyphenyl</em>)<em>ethylamine</em> (dopamine) to conjugate the boratecontaining anticancer drug bortezomib through a catechol metal binding in a pH-sensitive manner. This implantable magnetic nanofiber device can be exploited to apply hyperthermia with an alternating magnetic field and to achieve cancer cell-specific drug release to enable synergistic cancer therapy, which results in an improvement in both quality of life and patient compliance.

A wide variety of phenyl<em>ethylamine</em> derivatives were injected bilaterally into the nucleus accumbens of rat following a nialamide pretreatment and hyperactivity was recorded. <em>2</em>-Phenyl<em>ethylamine</em> was shown to induce a low intensity hyperactivity but the introduction of hydroxyl functions on to the phenyl ring at the 3- and/or 4-positions enhanced activity and m- and p-tyramine and dopamine each caused marked hyperactivity in the 3.4-<em>2</em>5 mug dosage range. Methylation of one hydroxyl function reduced activity (3-methoxy-4-hydroxy- and 3-hydroxy-4-methoxy-phenyl<em>ethylamine</em>); <em>2</em>(<em>3,4</em>-methylenedioxyphenyl) <em>ethylamine</em> was inactive. Agents with substitution of the side chain, such as noradreline, d-amphetamine and alpha-methyldopamine, were all shown to induce marked hyperactivity at doses of 1.6-<em>2</em>5 mug. Alterations in the chain length markedly reduced activity (4-(<em>3,4</em>-<em>dihydroxyphenyl</em>) butylamine, <em>3,4</em>-dihydroxybenzylamine). A variety of N-substituted compounds were shown to be potent inducers of hyperactivity from the nucleus accumbens (adrenaline, epinine, N-ethyldopamine, N-isopropyl-dopamine, isoprenaline) (0.<em>2</em>-<em>2</em>5 mug). However, N-methyl-N-isopropyldopamine showed only weak activity and N,N-dimethyldopamine was inactive. All hyperactivity effects were shown to be dose-dependent. The hyperactivities induced by dopamine, noradrenaline and isoprenaline were each inhibited in a dose-dependent manner by subsequent injections of fluphenazine (1.<em>2</em>5-<em>2</em>5 mug) into the nucleus accumbens, although no reductions were recorded following similar injections of saline, solvent, <em>2</em>% procaine, 50 mug propranolol or 50 mug piperoxan.

<em>2</em>-(Fluoromethyl)-3-(<em>3,4</em>-<em>dihydroxyphenyl</em>)alanine [alpha-FM-Dopa (I)] causes rapid, time-dependent, stereospecific, and irreversible inhibition of hog kidney aromatic amino acid (Dopa) decarboxylase. The inactivation occurs with loss of both the carboxyl carbon and fluoride from I and results in the stoichimetric formation of a covalent enzyme-inhibitor adduct. The data are consistent with I being a suicide inactivator of the enzyme, and a plausible mechanism for the inactivation process is presented. The inactivation is highly efficient in that there is essentially no enzymatic turnover of I to produce the corresponding amine, 1-(fluoromethyl)-<em>2</em>-(<em>3,4</em>-<em>dihydroxyphenyl</em>)<em>ethylamine</em> [alpha-FM-dopamine (II)]. Amine II is also a potent inactivator of the enzyme. In vivo compound I is found to inactivate both brain and peripheral (liver) Dopa decarboxylase activity. The possible significance of these data with respect to the known antihypertensive effect of I is discussed.

In order to elucidate the coordination state of water molecules in the Cu(II) site of dopamine [( <em>3,4</em>-<em>dihydroxyphenyl</em>)<em>ethylamine</em>] beta-monooxygenase, measurements of the paramagnetic 1H nuclear magnetic relaxation rate of solvent water in the enzyme solution containing cyanide or azide as an exogenous ligand were carried out to obtain the values of intrinsic paramagnetic relaxation rate decrements Rp1 and Rp<em>2</em> for the ligand-enzyme 1:1 and <em>2</em>:1 complexes, respectively. Rp1 (percent) values were 53 (pH 5.5) and 5<em>2</em> (pH 7.0) for cyanide and 38 (pH 5.5) and 3<em>2</em> (pH 7.0) for azide, while Rp<em>2</em> (percent) values were 98 (pH 5.5) and 96 (pH 7.0) for azide. Although no Rp<em>2</em> values for cyanide were obtained because of its reducing power at the Cu(II) site, the Rp1 and Rp<em>2</em> values obtained above prove that the Cu(II) center has two coordinated water molecules that are exchangeable for exogenous ligands at either pH. Supporting evidence was provided by electron paramagnetic resonance (EPR) titration, in which the enzyme solution containing cyanide-enzyme (1:1) complex in an equal proportion to uncomplexed enzyme gave an observed paramagnetic relaxation rate decrement, Rp, of <em>2</em>3%. Another characteristic of the Rp1 and Rp<em>2</em> values was their invariability with respect to pH, indicating that the three-dimensional structure of the Cu(II) site is pH-invariant within the range examined. Binding constants of ligand to enzyme Kb1 and Kb<em>2</em> for 1:1 and <em>2</em>:1 complex formation, respectively, were also determined through an analysis of the Rp values; it was found that Kb1 was larger than Kb<em>2</em> irrespective of pH. (ABSTRACT TRUNCATED AT <em>2</em>50 WORDS)

The stereochemistry of the bovine plasma amine oxidase catalyzed oxidation of <em>2</em>-(<em>3,4</em>-<em>dihydroxyphenyl</em>)-<em>ethylamine</em> (domapine) has been investigated by comparing 3H/14C ratios of <em>3,4</em>-dibenzyloxyphenethyl alcohols, derived from <em>3,4</em>-<em>dihydroxyphenyl</em>acetaldehydes, to starting dopamines chirally labeled at C-1 and C-<em>2</em>. The oxidation of [<em>2</em>RS-3H]-, [<em>2</em>R-3H]-, and [<em>2</em>S-3H]dopamine leads to products which have retained 53, 59, and 47% of their tritium. Similarly, oxidation of [1RS-3H]-, [1R-3H]-, and [1S-3H]dopamine leads to an 80, 80, and 9<em>2</em>% retention of tritium. The configurational purity of tritium at C-<em>2</em> of dopamine and C-1 of the dopamine precursor 3-methoxy-4-hydroxyphen<em>ethylamine</em> has been confirmed employing dopamine-beta-hydroxylase (specific for the pro-R hydrogen at C-<em>2</em>) and pea seedling amine oxidase (specific for the pro-S hydrogen at C-1). In addition, chromatographically resolved isozymes of bovine plasma amine oxidase have been demonstrated to lead to the same stereochemical result as pooled enzyme fractions. We have been able to rule out carbon interchange and tritium transfer in the <em>ethylamine</em> side chain of dopamine as the source of the apparent nonstereospecificity. Estimated primary tritium isotope effects are 1 for [<em>2</em>-3H]dopamines and 5--6 and <em>2</em>6--34 for [1R-3H]- and [1S-3H]dopamine, respectively. We propose the presence of alternate dopamine binding modes, characterized by absolute but opposing stereochemistries and differential primary tritium isotope effects at C-1.

Dopamine (<em>2</em>-(<em>3,4</em>-<em>dihydroxyphenyl</em>)<em>ethylamine</em>) is known as a natural chemical neurotransmitter and is also a cytotoxic and genotoxic molecule for cell apoptosis. In this work, the interaction of DNA with dopamine was investigated. Though the electrostatic interaction of DNA and dopamine was weak in aqueous solution, dopamine condensed circular pBR3<em>2</em><em>2</em> DNA into toroids on the mica surface cooperatively with ethanol. The formed DNA toroids came from the shrinking of DNA that was driven by ethanol-enhanced DNA-dopamine electrostatic interaction. The size of the DNA toroids could be modulated by varying the concentration of dopamine. This study offers useful information about the DNA condensation induced by monovalent cations and the sample preparation for AFM measurement and application. On the other hand, this work provides the potential strategies to prepare morphology and size controllable DNA condensates, which have valuable applications in gene transfection and nanotechnology.

Chemically modified electrodes are widely employed in electroanalytical chemistry and an important goal is to strongly anchor redox mediators on the electrode surface. In this work, indium tin oxide (ITO) electrodes have been coated with PEDOT:PSS that has been ferrocene-functionalized, by a two-step procedure consisting of the electrodeposition of PEDOT-N₃ followed by copper-catalyzed azide-alkyne cycloaddition of ethynylferrocene. The coated electrodes have been characterized by XPS, showing successful ferrocene immobilization, by AFM, and by cyclic voltammetry (CV), which is dominated by the stable and highly reversible response of ferrocene. The electrocatalytical performance of the device is assessed by analyzing <em>3,4</em>-<em>dihydroxyphenyl</em> <em>ethylamine</em>, also commonly known as dopamine (DA). The sensor presents a linear range between 0.01 and 0.9 mM, a mean sensitivity of 196 mA M^-1 cm^-<em>2</em> and a limit of detection (LoD) of 1 µM.

N-<em>2</em>,<em>2</em>,<em>2</em>,-Trifluoroethyl-<em>2</em>-(<em>3,4</em>-<em>dihydroxyphenyl</em>)<em>ethylamine</em> was synthesized and compared to N-ethyl-<em>2</em>-(<em>3,4</em>-<em>dihydroxyphenyl</em>)-<em>ethylamine</em> and dopamine for activity on adenylate cyclase in the rat striatum. Both dopamine and N-ethyl-<em>2</em>-(<em>3,4</em>-<em>dihydroxyphenyl</em>)<em>ethylamine</em> stimulated adenylate cyclase activity in a dose-dependent fashion. The N-trifluoroethyldopamine analog at 1 x 10(-4) M induced a weak effect. The compounds were evaluated further by studying their relaxant effects in isolated rabbit renal and ear arteries. Both the N-ethyl- and N-trifluoroethyldopamine analogs produced a relaxant effect but demonstrated no selectivity for dopamine receptors.

The lower rim functionalized hexahomotrioxacalix[3]arene derivatives cone-3 and cone-5 bearing three benzyl and three N,N-diethyl-<em>2</em>-aminoethoxy groups, respectively, were synthesized from triol 1. Their complexation with <em>2</em>-(<em>3,4</em>-<em>dihydroxyphenyl</em>)<em>ethylamine</em> (dopamine), 5-hydroxytryptamine (serotonin), and <em>2</em>-phenyl<em>ethylamine</em> (phen<em>ethylamine</em>), which have biologically important activities, has been studied by (1)H-NMR spectroscopy. The chemical shifts of the aromatic protons of the host and guest molecules and the up-field shifts of the ethyl protons of the guest molecules strongly suggest the formation of inclusion complexes in solution. The formation of the host-guest complexes is assisted by a hydrogen bond and/or an electrostatic interaction between the host and ammonium ion (RNH(3)(+)) of the guest. The structures of receptors cone-3 and cone-5 have been determined by X-ray crystallography.

In present work, a LiP enzyme producing bacterium was isolated form textile wastewater and sludge sample and identified as Bacillus albus by 16S rRNA gene sequencing analysis. This bacterium decolorized 99.<em>2</em>7 % MB dye and removed 83.87 % COD within 6 h at 30 °C, pH 7, 100 rpm and 100 mg/l of dye concentration in presence of glucose and yeast extract as carbon and nitrogen source, respectively. The bacterium also produced LiP enzyme of molecular weight ∼48 kDa, characterized by SDS-PAGE analysis. Different metabolites like monomethylthionine, thionin, (E)-<em>2</em>-(3-Oxopropylidene)-<em>2</em>H-benzo[b][1,4] thiozine-3-carboxylic acid, N-(<em>3,4</em>-<em>dihydroxyphenyl</em>)-N-methylformamide, <em>ethylamine</em>, water and carbon dioxide produced during treatment process were characterized by FT-IR and LC-MS analysis. Further, the toxicity assessment results showed that the toxicity of bacteria treated dye solution was reduced significantly allowing 90 % seed germination indicating that the isolated bacterium B. albus has high potential to decolorize and detoxify MB dye for environmental safety.

Keywords: Degradation; LC–MS analysis; Lignin peroxidase; Methylene blue; Phytotoxicity.

The interactions of dopamine [<em>2</em>-(<em>3,4</em>-<em>Dihydroxyphenyl</em>)<em>ethylamine</em>, (Dop^-)] with cadmium(II), copper(II) and uranyl(VI) were studied in NaCl(aq) at different ionic strengths (0 ≤ <i>I</i>/mol dm^-3 ≤ 1.0) and temperatures (<em>2</em>88.15 ≤ <i>T</i>/K ≤ 318.15). From the elaboration of the experimental data, it was found that the speciation models are featured by species of different stoichiometry and stability. In particular for cadmium, the formation of only MLH, ML and ML_<em>2</em> (M = Cd^<em>2</em>+; L = dopamine) species was obtained. For uranyl(VI) (UO_<em>2</em>^<em>2</em>+), the speciation scheme is influenced by the use of UO_<em>2</em>(acetate)_<em>2</em> salt as a chemical; in this case, the formation of ML_<em>2</em>, MLOH and the ternary MLAc (Ac = acetate) species in a wide pH range was observed. The most complex speciation model was obtained for the interaction of Cu^<em>2</em>+ with dopamine; in this case we observed the formation of the following species: ML_<em>2</em>, M_<em>2</em>L, M_<em>2</em>L_<em>2</em>, M_<em>2</em>L_<em>2</em>(OH)_<em>2</em>, M_<em>2</em>LOH and ML_<em>2</em>OH. These speciation models were determined at each ionic strength and temperature investigated. As a further contribution to this kind of investigation, the ternary interactions of dopamine with UO_<em>2</em>^<em>2</em>+/Cd^<em>2</em>+ and UO_<em>2</em>^<em>2</em>+/Cu^<em>2</em>+ were investigated at <i>I</i> = 0.15 mol dm^-3 and <i>T</i> = <em>2</em>98.15K. These systems have different speciation models, with the MM'L and M_<em>2</em>M'L_<em>2</em>OH [M = UO_<em>2</em>^<em>2</em>+; M' = Cd^<em>2</em>+ or Cu^<em>2</em>+, L = dopamine] common species; the species of the mixed Cd^<em>2</em>+ containing system have a higher stability with respect the Cu^<em>2</em>+ containing one. The dependence on the ionic strength of complex formation constants was modelled by using both an extended Debye-Hückel equation that included the Van't Hoff term for the calculation of the formation enthalpy change values and the Specific Ion Interaction Theory (SIT). The results highlighted that, in general, the entropy is the driving force of the process. The quantification of the effective sequestering ability of dopamine towards the studied cations was evaluated by using a Boltzmann-type equation and the calculation of pL_0.5 parameter. The sequestering ability was quantified at different ionic strengths, temperatures and pHs, and this resulted, in general, that the pL_0.5 trend was always: UO_<em>2</em>^<em>2</em>+ > Cu^<em>2</em>+ > Cd^<em>2</em>+.

Keywords: catechol; chemical speciation; metal complexes; sequestration; stability constants.

The interactions of dopamine [<em>2</em>-(<em>3,4</em>-<em>Dihydroxyphenyl</em>)<em>ethylamine</em>, (Dop^-)] with methylmercury(II) (CH₃Hg⁺), magnesium(II), calcium(II), and tin(II) were studied in NaCl(aq) at different ionic strengths and temperatures. Different speciation models were obtained, mainly characterized by mononuclear species. Only for Sn^<em>2</em>+ we observed the formation of binuclear complexes (M_<em>2</em>L_<em>2</em> and M_<em>2</em>LOH (charge omitted for simplicity); M = Sn^<em>2</em>+, L = Dop^-). For CH₃Hg⁺, the speciation model reported the ternary MLCl (M = CH₃Hg⁺) complex. The dependence on the ionic strength of complex formation constants was modeled by using both an extended Debye-Hückel equation that included the Van't Hoff term for the calculation of enthalpy change values of the formation and the Specific Ion Interaction Theory (SIT). The results highlighted that, in general, the entropy is the driving force of the process. The sequestering ability of dopamine towards the investigated cations was evaluated using the calculation of pL_0.5 parameter. The sequestering ability trend resulted to be: Sn^<em>2</em>+ > CH₃Hg⁺ > Ca^<em>2</em>+ > Mg^<em>2</em>+. For example, at <i>I</i> = 0.15 mol dm^-3, <i>T</i> = <em>2</em>98.15 K and pH = 7.4, pL_0.5 = 3.46, <em>2</em>.63, 1.15, and <em>2</em>.<em>2</em>7 for Sn^<em>2</em>+, CH₃Hg⁺, Ca^<em>2</em>+ and Mg^<em>2</em>+ (pH = 9.5 for Mg^<em>2</em>+), respectively. For the Ca^<em>2</em>+/Dop^- system, the precipitates collected at the end of the potentiometric titrations were analyzed by thermogravimetry (TGA). The thermogravimetric calculations highlighted the formation of solid with stoichiometry dependent on the different metal:ligand ratios and concentrations of the starting solutions.

Keywords: catechol; chemical speciation; metal complexes; sequestration; stability constants.