Formation Of Amine Groups Research Articles

Biyomedikal Uygulamalar için Propolis Ekstresinin PET Kumaş Üzerine İmmobilizasyonu

Propolis has biological activity due to its wide variety of phenolic compound content. Propolis usage in many areas such as cosmetics, food, medicine, and biomedicals is becoming widespread day by day due to its antibacterial, antifungal, antiviral properties. In this study, phenolics extracted from propolis were covalently bonded and immobilized on the surface of polyethylene terephthalate (PET) fabric with the aim of developing a technical textile for biomedical applications. To do so, PET fabric was aminated, and then the phenolics were immobilized using polyethylene glycol diglycidyl ether (PEGDGE) as the crosslinking agent. Formation of amine groups in PET structure and immobilization of the phenolics were proved by ATR-FTIR spectrums. Water contact angle of PET being 121° decreased to 110° and 97° after the amination and the immobilization, respectively. Optical microscope images were taken to monitor morphological changes after the processes. DSC results revealed a new endothermic peak at around 40 °C for modified PET. Tensile tests showed that tensile strength of the fabric weakens upon modification, while a healing effect occurs during immobilization. Antibacterial tests revealed that propolis extract immobilized fabric has an antibacterial activity against gram negative (E. coli) bacteria.

Low-temperature dyeing of silk fabric using atmospheric pressure helium/nitrogen plasma

Silk fabric was plasma treated in an indigenously developed atmospheric pressure plasma reactor in the presence of helium and nitrogen (He/N2) gaseous mixture at a discharge voltage of 5 kV and frequency of 21–23 kHz. The samples were plasma treated for 1 to 10 min with a constant nitrogen flow of 50 ml/min. They were also plasma treated in varying nitrogen flow rates in the range of 33.3 to 225 ml/min, keeping a constant helium (He) flow rate at 450 ml/min. The effects of plasma treatment time and nitrogen (N2) gas flow rates on water wicking, physical and chemical properties of the fabric surface along with rate of dyeing were investigated in details. The formation of amine groups in the plasma treated samples helps in faster exhaustion of acid dye even at a lower temperature. It was possible to dye the plasma treated silk fabric at 40 oC temperature instead of 90 oC, as is used conventionally. Due to higher dye exhaustion, the plasma treated sample showed a deeper shade. The physical and chemical properties of the samples were analyzed using SEM, ATR-FTIR, secondary ion mass spectrometer (SIMS), and XRD. Results indicate that water took only 408 s and 309 s to travel up to a height of 6 cm in the plasma treated samples for 4 min and 10 min, respectively. This was much shorter as compared to 696 s observed in the untreated (control) sample. The effects of plasma treatment time and the amount of nitrogen (N2) gas flow had a similar effect on water wicking. The plasma treatment time and N2 gas flow rates showed only marginal effects on mechanical properties of silk.

Immobilisation of horseradish peroxidase onto monodisperse poly(glycidyl methacrylate) microspheres

The aim of this study was to immobilise horseradish peroxidase (HRP) onto poly(glycidyl methacrylate) (PGMA) microspheres. In this study, PGMA particles were synthesised by dispersion polymerization from the glycidyl methacrylate (GMA) monomer. The monomer conversion value was determined to be 89% by weight. The first step comprised opening of the epoxide rings and formation of amine groups on the particle surfaces. The characterised particles were used as micro-carriers for the immobilisation of HRP. Glutaraldehyde, as bifunctional reactive, has been used as the spacer arm in the second step of the covalent binding method. The optimum immobilisation conditions found are as follows: immobilisation time 10 min, pH 7.2, temperature 25°C, initial enzyme concentration 0.05 mg/ml. Kinetic parameters of native and immobilised enzyme, such as K m and V max values, have been calculated 2.33 mmol/l and 0.670 mmol/l per s for the native enzyme and for the immobilised enzyme 69.13 mmol/l and 0.175 mmol/l per s, respectively. The HRP immobilised microparticules were used to purify a textile bleaching solution in which excess H2O2 remains.

Formation of amine groups by plasma enhanced chemical vapor deposition and its application to DNA array technology

A plasma enhanced chemical vapor deposition (PECVD) method using plasma polymerized ethylenediamine (PPEDA) was employed to coat glass slides with amine functional groups. Fluorescein isothiocyanate (FITC) labeling indicated that the density of amine functional groups on these coated slides was affected by PECVD conditions, particularly deposition time. The PPEDA-coated slides were used for the development of DNA arrays. 5′-Amino-modified oligodeoxyribonucleotides (ODNs) and cDNA strands were immobilized onto PPEDA-coated slides and used for hybridization to labeled target strands. In addition, patterning of amine groups, which is a very useful technique for preparing high-density DNA arrays, was achieved by selectively depositing PPEDA films on specific areas of a glass surface. These results demonstrate that the formation of amine groups on glass slides by PECVD is an excellent tool for DNA array technology.

Oxidative damage to bovine serum albumin induced by hydroxyl radical generating systems of xanthine oxidase + EDTA−Fe 3+ and ascorbate + EDTA−Fe 3+

Oxidative damage to bovine serum albumin (BSA) was induced by hydroxyl radical (HO •) generating systems of xanthine oxidase (XO) + EDTA−Fe 3+ and ascorbate + EDTA−Fe 3+. Formation of bityrosine and loss of tryptophan were observed in the ascorbate + EDTA−Fe 3+ system and carbonyl formation was induced by both systems. Mannitol and ethanol very strongly inhibited the carbonyl and/or bityrosine formation, indicating that the oxidative damage to BSA was due to HO •. The sulfhydryl (SH) groups of BSA were very sensitive to the XO + EDTA−Fe 3+ but not to the ascorbate + EDTA−Fe 3+ system. Catalase but not hydroxyl radical scavengers or superoxide dismutase strongly inhibited the loss of SH groups, indicating that H 2O 2 is involved in their oxidation. Fragmentation of BSA was observed during exposure to the XO + EDTA−Fe 3+ and ascorbate + EDTA−Fe 3+ systems and the products presented a broad band on sodium dodecyl sulfate polyacrylamide gel electrophoresis. Little formation of amine groups was observed in these systems, indicating that little peptide bond cleavage occurred. BSA exposed to the ascorbate + EDTA−Fe 3+ system was more readily degraded by trypsin than that exposed to the XO + EDTA−Fe 3+ system. Elastase degraded BSA exposed to the ascorbate + EDTA−Fe 3+ system but not to the XO + EDTA−Fe 3+ system.