Construction of amperometric biosensor modified with conducting polymer/carbon dots for the analysis of catechol

Phenolic compounds used in food industries and pesticide industry, are environmentally toxic and pollute the rivers and ground water. For that reason, detection of phenolic compounds such as catechol by using simple, efficient and cost‐effective devices have been becoming increasingly popular. In this study, a suitable and a novel matrix was composed using a novel conjugated polymer, namely poly[1‐(5‐(4,8‐bis(5‐(2‐ethylhexyl)thiophen‐2‐yl)benzo[1,2‐b:4,5‐b']dithiophen‐2‐yl)furan‐2‐yl)‐5‐(2‐ethylhexyl)‐3‐(furan‐2‐yl)‐4H thieno[3,4‐c]pyrrole‐4,6(5H)‐dione] (PFTBDT) and carbon dots (CDs) to detect catechol. PFTBDT and CDs were synthesized and the optoelectronic properties of PFTBDT were investigated via electrochemical and spectroelectrochemical studies. Laccase enzyme was immobilized onto the constructed film matrix on the graphite electrode. The proposed biosensor was found to have a low detection limit (1.23 μM) and a high sensitivity (737.44 μA/mM.cm−2) with a linear range of 1.25–175 μM. Finally, the applicability of the proposed enzymatic biosensor was evaluated in a tap water sample and a satisfactory recovery (96–104%) was obtained for catechol determination.Publisher's Versio

Live Cell Imaging of Bone Marrow Stromal Cells on Nano-pitted and Polished Titanium Surfaces: A Micro-Incubator in vitro Approach

Current orthopedic implants are not conducive for optimal integration of the biomaterial with newly-formed tissue (osseointegration) inside a patient’s body. In this study, medical-rade Ti-6Al-4V was used as a substrate due to its biocompatibility and ability to facilitate cellular adhesion and proliferation. Live cell imaging was conducted on bone marrow stromal cells, genetically modified to express the green fluorescent protein (GFP), from the 24-96 hours growth period, with the first 24 hours of growth being held inside a lab-scale incubator. Periodic images were recorded on nanopitted anodized and polished Ti-6Al-4V substrates to study how substratestiffness influences adhesion and proliferation. Collected images were analyzed for mitosis, adhesion, and filopodia-stretchability using ImageJ, an image processing program. Images were enhanced in order to perform cell counts at 24, 48, 72, and 96 hours of growth. Continuous recordings were produced to account for the number of mitosis occurrences and cellular migration on each of the substrates. Based on the conducted experiments, it appears that polished Ti-6Al-4V has a higher cell adherence than “nanopitted” anodized surface and an improved rate of proliferation which may be because the cells once adhered on the nano-pitted surface have less ability to detach in-order to undergo mitosis.https://engagedscholarship.csuohio.edu/u_poster_2014/1004/thumbnail.jp

Selenophene-bearing low-band-gap conjugated polymers: tuning optoelectronic properties via fluorene and carbazole as donor moieties

In this study, two donor-acceptor (D-A)-type conjugated polymers, namely PQSeCz and PQSeFl, were designed and synthesized. Selenophene was incorporated as the pi-bridge and quinoxaline as an acceptor unit, while carbazole and fluorene were used as the donor units. Polymers were synthesized via palladium-catalyzed Suzuki polymerization reaction. All molecules were characterized by H-1 and C-13 NMR spectroscopy. The weight and number average molecular weights of the two polymers were determined by gel permeation chromatography. Electrochemical and spectroelectrochemical characterizations of the polymers were performed to investigate their optoelectronic properties. Oxidation potentials were 1.15 V/0.82 V and 1.11 V/0.82 V for PQSeCz and PQSeFl, respectively, while reduction potentials were - 1.26 V/- 1.14 V and - 1.48 V/- 1.20 V, respectively. In the visible region, maximum absorption wavelengths for the two polymers were 551 nm and 560 nm, respectively. Optical band gaps (Egop) were found from the lowest energy pi-pi* transition onsets as 1.67 eV for PQSeCz and 1.51 eV for PQSeFl, respectively. Both polymers showed good solubility in common solvents

Tuning molecular energy levels and band gap of two-dimensional benzo[1,2-b:4,5-b '] dithiophene and quinoxaline bearing polymers

Two novel donor-acceptor (D-A)-type two-dimensional (2-D) polymers of PBDTSeQ (P1) and PBDTFQ (P2) were synthesized and characterized where 4,8-bis[5-(2-ethylhexyl) thiophen-2-yl] benzo[1,2-b:4,5-b'] dithiophene (BDT) was used as the donor unit. 2,3-Bis(3,4-bis(octyloxy)phenyI)-5,8-dibromoquinoxaline was used as the acceptor moiety and selenophene and furan were utilized as n bridges. Optoelectronic properties of the polymers were examined by electrochemical and spectroelectrochemical characterizations. In cyclic voltammetry (CV) studies, both polymers were found to be ambipolar. In anodic region, oxidation potentials were observed as 1.45 V and 1.15 V for P1 and P2 respectively, while reduction potentials were 0.65 V and 0.92 V. In cathodic region, redox potentials were found to be -1.36 V/-1.32 V and -2.0 V/-1.51 V for P1 and -1.45 V/-1.05 V and -2.15 V/-1.45 V for P2. Both polymers showed good solubility in common solvents. The synthesized polymers were used as photoactive layers in solar cell devices. P1-based device (ITO/PEDOT:PSS/P1:PC71BM (1:3, w/w)/LiF/Al) provided the best performance with a PCE of 4.04%, a V-OC of 0.67 V, a Jsc of 13.94 mA/cm(2), and a FF of 43.3%

Synthesis of a Multifunctional Quinoxaline and Benzodithiophene Bearing Polymer and Its Electrochromic Device Applications

A quinoxaline (Qx) and benzodithiophene (BDT) comprising of random copolymers, namely poly(5-(6-(5-(4,8-bis((2-ethylhexyl)oxy)benzo[1,2-b:4,5-b ']dithiophen-2-yl)-4-(2-ethylhexyl)thiophen-2-yl)-4,8-bis ((2-ethylhexyl)oxy)benzo[1,2-b:4,5-b ']dithiophen-2-yl)-2,3-bis(3,4-bis(octyloxy)phenyl)quinoxaline) (PQBT), is synthesized via Stille polycondensation reaction. To investigate the effect of the pi-bridge on the electrochromic properties, 3-(2-ethylhexyl) thiophene is incorporated the between Qx and BDT moiety. The resulting random copolymer is characterized by NMR spectroscopy, gel permeation chromatography (GPC), attenuated total reflectance-Fourier-transform infrared spectroscopy (ATR-FTIR), and scanning electron microscopy (SEM). PQBT exhibits ambipolar and multichromic characteristics and is highly soluble in common solvents. Optoelectronic studies reveal two well-separated absorption bands having maxima at 500 and 532 nm with 1.83 eV optical band gap (E-g(op)). PQBT exhibits orange color in the neutral state with brown, green, and blue colors in the intermediate, oxidized, and reduced states, respectively. Subsequently, a PQBT and poly-3,4-ethylenedioxythiophene (PEDOT)-bearing prototype bilayer electrochromic device working between orange and blue colors is constructed and characterized

Selenophene-containing conjugated polymers for supercapacitor electrodes

In recent years, studies on conjugated polymers have strengthened the researchers' thought that such polymers can play an essential role in developing new generation energy storage devices. Hence conjugated polymer supercapacitor studies have accelerated. In the present work, selenophene-containing conjugated polymers previously synthesized via palladium-catalyzed Suzuki polymerization reaction were used in the preparation of conjugated polymer-based supercapacitor electrodes. The structure and surface morphology of conjugated polymers were determined using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The selenophene-containing two conjugated polymer electrodes (ITO/Polymer) were fabricated. The electrochemical behavior of the conjugated polymer electrodes was evaluated through cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The specific capacity of ITO/CP1 electrode at 5 mV/s are 161.2 and 47 (Fg(-1)) for 0.1 mg and 1.2 mg, respectively. The specific capacity of ITO/CP2 at 5 mV/s electrode are 511 and 108.85 (Fg(-1)) for 0.08 mg and 0.70 mg, respectively. The time constants were determined as 10 and 625 ms for ITO/CP1 and CP2/ITO electrodes, respectively

Synthesis of a Multifunctional Quinoxaline and Benzodithiophene Bearing Polymer and Its Electrochromic Device Applications

A quinoxaline (Qx) and benzodithiophene (BDT) comprising of random copolymers, namely poly(5-(6-(5-(4,8-bis((2-ethylhexyl)oxy)benzo[1,2-b:4,5-b ']dithiophen-2-yl)-4-(2-ethylhexyl)thiophen-2-yl)-4,8-bis ((2-ethylhexyl)oxy)benzo[1,2-b:4,5-b ']dithiophen-2-yl)-2,3-bis(3,4-bis(octyloxy)phenyl)quinoxaline) (PQBT), is synthesized via Stille polycondensation reaction. To investigate the effect of the pi-bridge on the electrochromic properties, 3-(2-ethylhexyl) thiophene is incorporated the between Qx and BDT moiety. The resulting random copolymer is characterized by NMR spectroscopy, gel permeation chromatography (GPC), attenuated total reflectance-Fourier-transform infrared spectroscopy (ATR-FTIR), and scanning electron microscopy (SEM). PQBT exhibits ambipolar and multichromic characteristics and is highly soluble in common solvents. Optoelectronic studies reveal two well-separated absorption bands having maxima at 500 and 532 nm with 1.83 eV optical band gap (E-g(op)). PQBT exhibits orange color in the neutral state with brown, green, and blue colors in the intermediate, oxidized, and reduced states, respectively. Subsequently, a PQBT and poly-3,4-ethylenedioxythiophene (PEDOT)-bearing prototype bilayer electrochromic device working between orange and blue colors is constructed and characterized

Non-fullerene organic photovoltaics based on thienopyrroledione comprising random copolymers; effect of alkyl chains

Two new random donor-acceptor (D-A) copolymers, signed as P1 and P2, were designed and synthesized. Electrochemical and spectroelectrochemical measurements were performed to investigate absorption, energy levels, electronic and optical band gaps for comparison. The polymers were used as donor polymers in the active layer to fabricate non-fullerene, bulk heterojunction (BHJ) organic photovoltaics (OPVs). Investigations were carried out through the conventional BHJ structure; ITO/PEDOT: PSS/Active Layer/LiF/Al, where active layer consists of 3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone))-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3-d:2′,3′-d']-s-indaceno[1,2-b:5,6-b']dithiophene (ITIC) as the acceptor and thienopyrroledione containing donors. The device based on P1:ITIC(1:1) blend with a thickness of 161 nm gave the best performance with a power conversion efficiency (PCE) of 7.94%, an open-circuit voltage (VOC) of 0.86 V, a short-current density (JSC) of 18.45 mA cm−2 and a fill factor (FF) of 50.12%. The highest PCE obtained from P2 based organic solar cell is 1.96%. P2 exhibited low solubility attributed to the lack of alkyl groups enhancing polymer solubility, electronic properties, and photovoltaic performances. The research outputs exhibit that introduction of alkyl chains on the polymer backbone can enhance device performance

Improving Pancreatic Islet In Vitro Functionality And Transplantation Efficiency By Using Heparin Mimetic Peptide Nanofiber Gels

Pancreatic islet transplantation is a promising treatment for type I diabetes. However, viability and functionality of the islets after transplantation are limited due to loss of integrity and destruction of blood vessel networks. Thus, it is important to provide a proper mechanically and biologically supportive environment for enhancing both in vitro islet culture and transplantation efficiency. Here, we demonstrate that heparin mimetic peptide amphiphile (HM-PA) nanofibrous network is a promising platform for these purposes. The islets cultured with peptide nanofiber gel containing growth factors exhibited a similar glucose stimulation index as that of the freshly isolated islets even after 7 days. After transplantation of islets to STZ-induced diabetic rats, 28 day-long monitoring displayed that islets that were transplanted in HM-PA nanofiber gels maintained better blood glucose levels at normal levels compared to the only islet transplantation group. In addition, intraperitoneal glucose tolerance test revealed that animals that were transplanted with islets within peptide gels showed a similar pattern with the healthy control group. Histological assessment showed that islets transplanted within peptide nanofiber gels demonstrated better islet integrity due to increased blood vessel density. This work demonstrates that using the HM-PA nanofiber gel platform enhances the islets function and islet transplantation efficiency both in vitro and in vivo. (C) 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.Wo