Rukiye Ayranci

Peptide-modified conducting polymer as a biofunctional surface: monitoring of cell adhesion and proliferation

Here, we report the electropolymerization of 3-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)aniline monomer on indium tin oxide (ITO) glass and its use as a coating material for cell culture applications. Functional amino groups on the conducting polymer provide post-modification of the surface with the arginylglycylaspartic acid (RGD) peptide via EDC chemistry. Scanning electron microscopy, atomic force microscopy, and contact angle and surface conductivity measurements were carried out for the surface characterization. The peptide-conjugated surface was tested for adhesion and proliferation of several cell lines such as monkey kidney epithelial (Vero), human neuroblastoma (SH-SY5Y), and human immortalized skin keratinocyte (HaCaT). These cells were cultured on RGD-modified, polymer-coated ITO glass as well as conventional polystyrene surfaces for comparison. The data indicate that the RGD-modified surfaces exhibited better cell adhesion and proliferation among all surfaces compared. Cell imaging studies up to 72 h in length were performed on these surfaces using different microscopy techniques. Therefore, the novel biofunctional substrate is a promising candidate for further studies such as monitoring the effects of drugs and chemicals on cellular viability and morphology as well as cell-culture-on-a-chip applications.

Ferrocene-Functionalized 4-(2,5-Di(thiophen-2-yl)-1H-pyrrol-1- yl)aniline: A Novel Design in Conducting Polymer-Based Electrochemical Biosensors

Herein, we report a novel ferrocenyldithiophosphonate functional conducting polymer and its use as an immobilization matrix in amperometric biosensor applications. Initially, 4-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)amidoferrocenyldithiophosphonate was synthesized and copolymerized with 4-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)benzenamine at graphite electrodes. The amino groups on the polymer were utilized for covalent attachment of the enzyme glucose oxidase. Besides, ferrocene on the backbone was used as a redox mediator during the electrochemical measurements. Prior to the analytical characterization, optimization studies were carried out. The changes in current signals at +0.45 V were proportional to glucose concentration from 0.5 to 5.0 mM. Finally, the resulting biosensor was applied for glucose analysis in real samples and the data were compared with the spectrophotometric Trinder method.

Comparative investigation of spectroelectrochemical and biosensor application of two isomeric thienylpyrrole derivatives

In the present work, we performed a comparative investigation of spectroelectrochemical and biosensor application of isomeric thienylpyrrole derivatives. For this purpose two thienylpyrrole derivatives were synthesized characterized and electrochemically polymerized. Characterizations of the resulting polymers were performed by cyclic voltammetry (CV), UV-vis spectroscopy. Moreover, the spectroelectrochemical, electrochromic properties and biosensing applications of the polymer films were investigated. The resulting polymer films have distinct electrochromic properties and show five different colors. The 4-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)aniline (SNS-NH2) and 3-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)aniline P(SNS-mNH2) films show maximum optical contrast (ΔT%) of 41.5%, 25.4% at 431 nm, 422 nm with a response time of 1.5 s. For biosensing studies, P(SNS-NH2) and P(SNS-mNH2) were polymerized on graphite electrodes electrochemically and used as immobilization matrices. After electrochemical deposition, glucose oxidase (GOx) was immobilized on the modified electrodes as the model enzyme. Effects of the position of the amine group on spectroelectrochemical properties and biosensing capability of the polymers were investigated.

The effect of the monomer feed ratio and applied potential on copolymerization: investigation of the copolymer formation of ferrocene-functionalized metallopolymer and EDOT

Abstract In this study, we reported synthesis of ferrocene functioned conducting metallopolymer to enhance the understanding of properties of polymers. One of the crucial ways in the electrochromic polymer materials research was tuning color by means of copolymerization and change of polymer backbones and side groups. For this purpose, we synthesized copolymer of 4-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)amido ferrocenyl dithiophosphonate with EDOT via potentiodynamic electrolysis. Spectral and electrochemical characterizations of the copolymer were investigated. In addition, the spectral properties of the copolymers prepared by different applied potentials and different monomer feed ratio were studied. For the first time, copolymer composition and the monomer reactivity ratios were approximately calculated by using the spectral data.

Synthesis of a novel, fluorescent, electroactive and metal ion sensitive thienylpyrrole derivate

In this study, a novel, fluorescent, metal ion sensitive monomer called (E)-4-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)-N-(pyren-1-ylmethylene)aniline (PR–SNS) was synthesized. Good fluorescence properties for PR–SNS were successfully achieved, which emits blue. Furthermore, PR–SNS shows sensitive fluorescence changes when interacting with metal ions. The electrochemical properties of P(PR–SNS) were studied via spectroelectrochemistry, kinetic studies, and colorimetry measurements. The novel PR–SNS or its polymer might be a good candidate for the selective sensing of metal ions via smart florescent and electrochemical features.

Rhodamine functionalized conducting polymers for dual intention: electrochemical sensing and fluorescence imaging of cells

We report here the electrochemical co-polymerization of two functional monomers, one containing fluorescent rhodamine dye (RF) and the other monomer having amine groups (RD), onto electroactive Indium Tin Oxide (ITO) glass. After one step preparation of these surfaces, a three peptide called ArginylGlysylAspartic acid (RGD) was immobilized via EDC chemistry by using amine groups (P(RF-co-RD)/RGD) of the co-polymer, for further use in various bio-applications such as cell adhesion and imaging as well as electrochemical cell sensing. The resultant RGD bound and also fluorescent platforms were utilized as targeted adhesion materials towards integrin avb3 receptor positive (U87-MG) cells and the selectivity was checked by using HaCaT cells as a control. Finally, electrochemical measurements were carried out to characterize step by step surface modification and detection of cell attachment. As a result, P(RF-co-RD)/RGD is a promising material for multi-purpose uses, such as fluorescence imaging without the need for an additional dye for cell visualization and as a targeted adhesion and electrochemical cell sensing platform.

Synthesis of new ferrocenyldithiophosphonate derivatives: electrochemical, electrochromic, and optical properties

Abstract In this study, three ferrocenyl dithiophosphonate derivatives were synthesized and characterized by elemental analyses, IR, and NMR (1H-, 31P-) spectroscopy. Electroactivities of synthesized molecules were determined by cyclic voltammetry experiments. It was shown that all molecules were electroactive and only one of them that contained conjugated structure could polymerized by electrochemical experiments. Characterization of electrosynthesized metallopolymer was realized and electrochromic and spectroelectrochemical properties were investigated. The onset energy for the π–π* transition (electronic band gap), HOMO, and LUMO energy levels were calculated as 2.31, −4.44, and 2.13 eV, respectively. Switching time and optical contrast values of metallopolymer were found as 1.5 s and 41% at 435 nm, respectively, whereas these values were found as 2.5 s and 40%, respectively, at 700 nm.

Copolymer based multifunctional conducting polymer film for fluorescence sensing of glucose

A simple, rapid and effective fluorescence sensing platform has been fabricated using a fluorescent conducting polymer surface. For this purpose, a rhodamine based electroactive monomer (RDC) and a functional group containing monomer (SNS) have been copolymerized to develop a conducting polymer based sensor platform having a fluorescence and enzyme-binding surface on ITO electrode. The proposed fluorescence sensing mechanism for detection of glucose is related to the consumption of dissolved oxygen at the double layer of the electrode which is fluorescence quenching agent by glucose-GOx reaction. Concentration of glucose was investigated quantitatively from 0.05 to 1 mM via fluorescence signal measurement. This novel approach could be adapted for the production of various rapid and effective fluorescence sensing platforms for glucose.