Synthesis, characterization, thermal stability and electrochemical properties of ortho-imine-functionalized oligophenol via enzymatic oxidative polycondensation

WOS: 000439781600002Ortho-imine functionalized oligophenol was synthesized via enzymatic polymerization of 2-((4-nitrophenylimino) methyl) phenol (NPIMP). Enzymatic polymerization was catalyzed by Horseradish peroxidase (HRP) enzyme and hydrogen peroxide (H2O2) oxidizer yielded oligophenol with imine functionality on the side-chain. Effects of various factors including reaction pH, temperature and solvent system on the polymerization were studied. Optimum polymerization with the highest yield (96 %) and number-average molecular weight (M-n = 7300 g/mol, degree of polymerization approximate to 30) was accomplished using equivolume mixture of acetone/pH 7.0 phosphate buffer medium at 35 degrees C in 24 h under air. Characterization of the resulting oligomer was accomplished by ultraviolet-visible spectroscopy (UV-Vis), fourier transform infrared spectroscopy (FT-IR), H-1 and C-13 nuclear magnetic resonance (H-1 and C-13 NMR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), cyclic voltammetry (CV) and gel permeation chromatography (GPC). The polymerization involved elimination of hydrogen from NPIMP, and the oligomer possessed phenolic -OH end groups. The oligomer backbone was composed of oxyphenylene and phenylene repeat units. The optical band gaps (Eg) of NPIMP and oligo(NPIMP) were measured as 3.21 and 3.39 Eg, respectively. Thermal stability of the oligo(NPIMP) was also found to be relatively high, and lost 5 % of its mass at 175 degrees C and lost 50 % of its mass at 600 degrees C.Scientific and Technological Research Council of Turkey (TUBITAK) [115Z482]This research was partially supported by the Scientific and Technological Research Council of Turkey (TUBITAK) (115Z482)

Synthesis and characterization of imine-functionalized polyphenol via enzymatic oxidative polycondensation of a bisphenol derivative

WOS: 000370352800011Enzymatic oxidative polycondensation of a new bisphenol derivative 3,3'-((1E,1'E)-(1,3-phenylenebis(azanylylidene))bis(methanylylidene))diphenol, (3,3'-PBAMD), using horseradish peroxidase (HRP) enzyme and hydrogen peroxide (H2O2) oxidizer for initiation of the reaction, has been investigated in an equivolume mixture of an organic solvent (acetone, methanol, ethanol, dichloromethane, 1,4-dioxane and tetrahydrofuran) and phosphate buffer (pH = 5.0, 6.0, 7.0, 8.0 and 9.0) at different temperatures under air for 24 h. The resulting polymer, poly(3,3'-PBAMD), was characterized using ultraviolet-visible (UV-Vis), Fourier transform infrared (FT-IR), H-1 nuclear magnetic resonance (NMR), gel permeation chromatography (GPC) and thermogravimetric (TGA) analyses. Effects of solvent system, reaction temperature and pH on the polymerization have been investigated with respect to the yield and molecular weight (M-n) of the product. The optimum reaction condition in terms of the highest yield (81 %) and molecular weight (M-n = 10,500 g/mol, DP similar to 33) was achieved in an equivolume mixture of tetrahydrofuran/pH 7.0 phosphate buffer medium at 25 degrees C. Polymerization involved hydrogen elimination from the monomer, and terminal units of the polymer structure consisted of phenolic hydroxyl (-OH) groups at the ends. The polymer is mainly composed of a mixture of phenylene and oxyphenylene units according to H-1 NMR and FT-IR analyses. The resulted product has shown relatively high thermal stability against thermal decomposition, and 35 % of the initial weight of the sample (carbonaceous residue) remained after heating to 1000 degrees C.Turkish Ministry of National EducationE. G. graciously acknowledges the Turkish Ministry of National Education for his Ph.D. scholarship

?-amylase monitoring by a novel amperometric biosensor based on Au electrode: Its optimization, characterization, and application

PubMed ID: 21838534A low-cost and sensitive amperometric biosensor was developed for the determination of ?-amylase activity. The biosensor was constructed by immobilizing glucose oxidasegelatin via glutaraldehyde on the Au electrode surface. Measurements were carried out chronoamperometrically at -0.7 V. Several parameters such as glucose oxidase activity, gelatin amount, and glutaraldehyde percentage for cross-linking were optimized. Optimum pH, optimum temperature, repeatability, and storage stabilities of the biosensor were identified. Under the optimum experimental conditions, a linear calibration curve was obtained for ?-amylase between 0.819 and 13.110 U/ml. Sample analyses were carried out by detecting ?-amylase activities in bakers yeast samples. © 2012 Informa Healthcare USA, Inc

alpha-Amylase Monitoring by a Novel Amperometric Biosensor Based on Au Electrode: Its Optimization, Characterization, and Application

WOS: 000299696500012PubMed ID: 21838534A low-cost and sensitive amperometric biosensor was developed for the determination of alpha-amylase activity. The biosensor was constructed by immobilizing glucose oxidase-gelatin via glutaraldehyde on the Au electrode surface. Measurements were carried out chronoamperometrically at -0.7 V. Several parameters such as glucose oxidase activity, gelatin amount, and glutaraldehyde percentage for cross-linking were optimized. Optimum pH, optimum temperature, repeatability, and storage stabilities of the biosensor were identified. Under the optimum experimental conditions, a linear calibration curve was obtained for alpha-amylase between 0.819 and 13.110 U/ml. Sample analyses were carried out by detecting alpha-amylase activities in baker's yeast samples

Prognostic and diagnostic importance of the systemic immune-inflammation index in pediatric head trauma

Head trauma is a leading cause of mortality and morbidity in pediatric patients. The trauma itself leads to the activation of a biomolecular cascade of damage. Purinergic receptors and ATP release play an important role in the activation of astroglia, microglia, monocyte-macrophages, neutrophils, and T cells in this process. The systemic immune inflammation index can be easily calculated, cheap, only requires hemogram parameters, and does not include any subjective findings. Therefore, we believe that it could be a prognostic predictor and a diagnostic marker for pediatric head trauma cases. Our study was designed as a retrospective and single-center study. The study was conducted with pediatric patients who presented to the emergency department with isolated head trauma between June 15, 2022, and December 15, 2022. Demographic data, medical history, white blood count, platelet count, neutrophil count, systemic immune inflammation index (SIII), Glasgow Coma Score, and the presence of pathology on brain computed tomography were recorded on the case report form. The study was conducted with 112 cases. In cases with bleeding, the median value of GCS was significantly lower (p [Med-Science 2023; 12(3.000): 656-60