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Adsorption and Fenton oxidation of azo dyes by magnetite nanoparticles deposited on a glass substrate
(Elsevier, 2019) Unal, Bahar Ozbey; Bilici, Zeynep; Ugur, Naz; Isik, Zelal; Harputlu, Ersan; Dizge, Nadir; Ocakoglu, Kasim
Fenton oxidation is an efficient and useful method for wastewater treatment. To increase overall reaction efficiencies and inhibit environmental impacts, developing advanced catalysts are crucial in this matter. The main goal of this study was to investigate the catalytic activity of the magnetite (Fe2+Fe23+O42-, FeFe2O4, or Fe3O4) nanoparticles (NPs) coated borosilicate glass on the color removal of basic red 18 (BR18) and acid red 8 (AR88) azo dyes by adsorption and Fenton oxidation reaction. The efficiency of powder magnetite NPs was also tested to compare to magnetite NPs coated borosilicate glass. The effect of solution pH (2.5-9.0), catalyst loading (0.25-3.0 g/L), and dye concentration (0.1-0.3 mM) were tested to achieve maximum color removal efficiency using powder magnetite NPs. The color removal efficiencies were measured 44% at pH 9.0 and 76% at pH 3.5 for adsorption and Fenton oxidation of BR18 dye (0.1 mM). Moreover, the color removal efficiencies were measured 81% at pH 3.5 and 100% at pH 6.0 for adsorption and Fenton oxidation of AR88 dye (0.1 mM). The effect of hydrogen peroxide (H2O2) concentration (2.5-25 mM) was also optimized and 10 mM was found optimum H2O2 dosage for Fenton oxidation. However, magnetite NPs coated borosilicate glass enhanced maximum 77% and 82% color removal efficiencies for adsorption and Fenton oxidation of BR18 dye. Maximum 86% and 100% color removal efficiencies were obtained for adsorption and Fenton oxidation of AR88 dye. Stability of the powder magnetite NPs and magnetite NPs coated borosilicate glass catalyst was also investigated. The reusability of the catalyst showed that magnetite NPs coated borosilicate glass could be used at least 3 times without significant loss of activity compared to powder magnetite NPs for Fenton oxidation. The characterization of the catalyst was carried out using scanning electron microscope with energy dispersive X-ray spectroscopy (SEM-EDX), X-ray powder diffraction (XRD), and zeta potential analyses before and after adsorption.
Bimodal functionality of highly conductive nanostructured silver film towards improved performance of photosystem I-based graphene photocathode
(Elsevier Science Sa, 2025) Szalkowski, Marcin; Kiliszek, Malgorzata; Harputlu, Ersan; Izzo, Miriam; Unlu, C. Gokhan; Mackowski, Sebastian; Ocakoglu, Kasim
We present the novel design of photosystem I (PSI)-based biosolar cell, whereby conductive transparent electrode materials, such as ITO or FTO, are replaced with glass covered with silver island film. This nanostructured metallic layer combines high electric conductance with enhancing the absorption efficiency of the PSI biocatalyst via the plasmonic effect. We demonstrate strong enhancement of the photocurrent generated in the biohybrid electrode composed of oriented layers of PSI reaction centers due to plasmonic interactions of the PSI fluorophores and redox centres with the conductive silver island film.
Bor nitrür kuantum nokta-grafen hidrojel kompozitinin süper kapasitör uygulaması
(2024) Sert, Buse; Harputlu, Ersan
Bu çalışmada süperkapasitörler için kullanılacak yeni bir elektrot malzemesi olan bor nitrür kuantum nokta (BNKN) / indirgenmiş grafen oksit (rGO) hibrit yapısının sentezini ve elektrokimyasal uygulamalarına yer verilmiştir. BNKN’nin, grafen oksit (GO) ile aynı kristal yapıya sahip olması ve bunun sonucunda BNKN@rGO hibrit yapısının çok iyi elektriksel özellik gösteriyor olması tercih edilme sebeplerindendir. Hekzagonal bor nitrür (h-BN) nanoyapı tabanlı hibrit malzeme olan BNKN, termal kararlılıkları ve elektriksel iletkenlikleri sebepleriyle son yıllardaki çalışmalarda karşımıza çıkarken, grafen ise geniş spesifik yüzey alanına sahip olduğu için süperkapasitör çalışmalarında sıklıkla tercih edilmektedir. Ayrıca, grafenin kapasitans değerini geliştirmek için bu yapıya farklı nanomalzemeler eklenmesinin ana sebebi karbon malzemelerin elektron verici özelliklerinin geliştirilmesidir. Bundan dolayı, süperkapasitörlerde kullanılacak BNKN@rGO hibrit elektrotunun elektrokimyasal aktiviteyi arttıracağı düşünülerek spesifik kapasitans değeri ölçülmüştür. Elektrokimyasal çalışmalar sonucunda, BNKN@rGOH hibrit yapısının 5 mvs-1 tarama hızında 207.5 F/g yüksek kapasitans değeri elde edilmiştir. Ayrıca 1.000 döngüde %88.9’luk döngüsel stabilite performansı sergilemiştir.
Combustion Characteristics of r-GO/g-C3N4/LaFeO3 Nanohybrids Loaded Fuel Droplets
(Taylor and Francis Ltd., 2023) Küçükosman, Rıdvan; Değirmenci, Hüseyin; Sert, Buse; Yontar, Ahmet Alper; Harputlu, Ersan; Ocakoğlu, Kasım
Graphene oxide (GO), reduced graphene oxide (r-GO) and graphitic carbon nitride (g-C3N4) are two-dimensional carbon-based nanosheets that show promise in reducing emissions with their superior catalytic activity in capturing species such as NOx and CO2 thanks to their oxygen- based functional groups and active edges on their surfaces. These active surfaces also provide a scheme for the substitution of materials with high calorific value or high catalytic activity for combustion. This study focuses on the fabrication of functional nanohybrid structures customized for combustion with LaFeO3 metal oxide nanoparticles substituted on these nanosheets and their effect on the combustion behavior of gaso-line. The fabrication of r-GO/g-C3N4/LaFeO3 nanohybrid structures was carried out by a two-step hydrothermal method. The structural character-izations of the samples were confirmed by SEM and XRD analyses and their chemical states were confirmed by Raman and XPS techniques. Combustion experiments were carried out by droplet scale combustion of gasoline-based nanofuel droplets containing dilute (0.2 wt.%) and high (0.7 wt.%) concentrations of GO, r-GO, g-C3N4, g-C3N4/LaFeO3 and r-GO/g- C3N4/LaFeO3 nanoparticles. The experimental process was recorded with a high-speed camera and a thermal camera. The nanofuel droplets con-taining 0.2 wt.% g-C3N4/LaFeO3 nanohybrid structures had the highest maximum flame temperature of 519 K, and the nanofuel droplets con-taining 0.7 wt.% r-GO/g-C3N4/LaFeO3 particles had the highest maximum aggregate temperature of 1177 K. The ignition delay time decreased for all droplets with 0.2 wt.% and 0.7 wt.% particle loadings. At 0.2 wt.% concentration, g-C3N4 doped fuel droplets exhibited the lowest extinction time, while at 0.7 wt.% concentration, the lowest extinction time was measured for r-GO/g-C3N4/LaFeO3 doped fuel droplets. Fuel droplets containing g-C3N4 particles had the highest burning rate and were the fastest extinguishing fuel droplets in the electric field. In this study, it has been demonstrated that the combustion rate and energy value of hydro-carbon fuels can be increased and soot formation can be reduced at the same time with the new generation of graphene-based functional mate-rials to be created, and thus, many combustion problems can be solved simultaneously with these functional particles.
Development of a Novel Nanoarchitecture of the Robust Photosystem I from a Volcanic Microalga Cyanidioschyzon merolae on Single Layer Graphene for Improved Photocurrent Generation
(Mdpi, 2021) Izzo, Miriam; Jacquet, Margot; Fujiwara, Takayuki; Harputlu, Ersan; Mazur, Radoslaw; Wrobel, Piotr; Goral, Tomasz
Here, we report the development of a novel photoactive biomolecular nanoarchitecture based on the genetically engineered extremophilic photosystem I (PSI) biophotocatalyst interfaced with a single layer graphene via pyrene-nitrilotriacetic acid self-assembled monolayer (SAM). For the oriented and stable immobilization of the PSI biophotocatalyst, an His(6)-tag was genetically engineered at the N-terminus of the stromal PsaD subunit of PSI, allowing for the preferential binding of this photoactive complex with its reducing side towards the graphene monolayer. This approach yielded a novel robust and ordered nanoarchitecture designed to generate an efficient direct electron transfer pathway between graphene, the metal redox center in the organic SAM and the photo-oxidized PSI biocatalyst. The nanosystem yielded an overall current output of 16.5 mu A center dot cm(-2) for the nickel- and 17.3 mu A center dot cm(-2) for the cobalt-based nanoassemblies, and was stable for at least 1 h of continuous standard illumination. The novel green nanosystem described in this work carries the high potential for future applications due to its robustness, highly ordered and simple architecture characterized by the high biophotocatalyst loading as well as simplicity of manufacturing.
Diazonium-Based Covalent Molecular Wiring of Single-LayerGraphene Leads to Enhanced Unidirectional PhotocurrentGeneration through the p-doping Effect
(Amer Chemical Soc, 2022) Jacquet, Margot; Osella, Silvio; Harputlu, Ersan; Palys, Barbara; Kaczmarek, Monika; Nawrocka, Ewa K.; Rajkiewicz, Adam A.
Development of robust and cost-effective smart materials requiresrational chemical nanoengineering to provide viable technological solutions for awide range of applications. Recently, a powerful approach based on theelectrografting of diazonium salts has attracted a great deal of attention due to itsnumerous technological advantages. Several studies on graphene-based materialsreveal that the covalent attachment of aryl groups via the above approach could leadto additional beneficial properties of this versatile material. Here, we developed thecovalently linked metalorganic wires on two transparent, cheap, and conductivematerials:fluorine-doped tin oxide (FTO) and FTO/single-layer graphene (FTO/SLG). The wires are terminated with nitrilotriacetic acid metal complexes, whichare universal molecular anchors to immobilize His6-tagged proteins, such asbiophotocatalysts and other types of redox-active proteins of great interest inbiotechnology, optoelectronics, and artificial photosynthesis. We show for thefirsttime that the covalent grafting of a diazonium salt precursor on two differentelectron-rich surfaces leads to the formation of the molecular wires that promote p-doping of SLG concomitantly with a significantlyenhanced unidirectional cathodic photocurrent up to 1 mu Acm-2. Density functional theory modeling reveals that the exceptionallyhigh photocurrent values are due to two distinct mechanisms of electron transfer originating from different orbitals/bands of thediazonium-derived wires depending on the nature of the chelating metal redox center. Importantly, the novel metalorganic interfacesreported here exhibit minimized back electron transfer, which is essential for the maximization of solar conversion efficiency.
Enhancement of direct electron transfer in graphene bioelectrodes containing novel cytochrome c553 variants with optimized heme orientation
(Elsevier Science Sa, 2021) Izzo, Miriam; Osella, Silvio; Jacquet, Margot; Kiliszek, Malgorzata; Harputlu, Ersan; Starkowska, Alicja; Lasica, Anna
The highly efficient bioelectrodes based on single layer graphene (SLG) functionalized with pyrene self-assembled monolayer and novel cytochrome c(553) (cyt c(553)) peptide linker variants were rationally designed to optimize the direct electron transfer (DET) between SLG and the heme group of cyt. Through a combination of photoelectrochemical and quantum mechanical (QM/MM) approaches we show that the specific amino acid sequence of a short peptide genetically inserted between the cyt c(553) - holoprotein and the surface anchoring C-terminal His s -tag plays a crucial role in ensuring the optimal orientation and distance of the heme group with respect to the SLG surface. Consequently, efficient DET occurring between graphene and cyt c(553) leads to a 20-fold enhancement of the cathodic photocurrent output compared to the previously reported devices of a similar type. The QM/MM modeling implies that a perpendicular or parallel orientation of the heme group with respect to the SLG surface is detrimental to DET, whereas the tilted orientation favors the cathodic photocurrent generation. Our work confirms the possibility of fine-tuning the electronic communication within complex bio-organic nanoarchitectures and interfaces due to optimization of the tilt angle of the heme group, its distance from the SLG surface and optimal HOMO/LUMO levels of the interacting redox centers. (C) 2021 The Authors. Published by Elsevier B.V.
Evaluating the simultaneous electrochemical determination of antineoplastic drugs using LaNiO3/g-C3N4@RGH nanocomposite material
(Elsevier, 2024) Bouali, Wiem; Erk, Nevin; Sert, Buse; Harputlu, Ersan
A novel electrochemical sensor based on LaNiO3/g-C3N4@RGH nanocomposite material was developed to simultaneously determine Ribociclib (RIBO) and Alpelisib (ALPE). Ribociclib and Alpelisib are vital anticancer medications used in the treatment of advanced breast cancer. The sensor exhibited excellent electrocatalytic activity towards the oxidation of RIBO and ALPE, enabling their simultaneous detection. The fabricated sensor was characterized using various techniques, including energy dispersive X-ray (EDX), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XR), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS), which confirmed the successful synthesis of the LaNiO3/g-C3N4@RGH composite material. Electrochemical characterization revealed enhanced conductivity and lower resistance of the modified electrode compared to the bare electrode. The developed sensor exhibited high repeatability, reproducibility, stability, and selectivity toward RIBO detection. Furthermore, the sensor displayed high sensitivity with low detection limits of 0.88 nM for RIBO and 6.1 nM for ALPE, and linear ranges of 0.05–6.2 ?M and 0.5–6.5 ?M, respectively. The proposed electrochemical sensor offers a promising approach for simultaneously determining RIBO and ALPE in pharmaceutical formulations and biological samples with recovery data of 98.7–102.0 %, providing a valuable tool for anticancer drug analysis and clinical research.
Fabrication of LaFeO3/g-C3N4@reduced graphene oxide 3-dimensional nanostructure supercapacitor
(Springer, 2022) Harputlu, Ersan; Gecgel, Cihan
This paper describes the electrochemical studies of a magnificent new ternary complex whose nanoarchitecture consists of lanthanum iron oxide (LaFeO3) perovskite, graphitic carbon nitride (g-C3N4), and reduced graphene-based hydrogel (GH) for the supercapacitor (SC) approach. For this purpose, GH was used as the backbone structure in the main body of the hybrid structure. A hybrid form of g-C3N4 and GH was used in the appropriate architecture required to improve the usage area of LaFeO3 perovskite structure in supercapacitor applications. Thus, by increasing the interaction surface area between the electrode-electrolyte of the supercapacitor made with LaFeO3, the specific capacitance amount and long cycle life of the SC were increased. Within this context, the advanced three-dimensional (3D) LaFeO3/g-C3N4@GH hydrogel is created by using basic hydrothermal and freeze-drying processes. Electrochemical investigations revealed that LaFeO3/g-C3N4@GH has improved capacitive performance, with a specific capacitance (C-s) of 652.12 F/g at a scan rate of 5 mV/s. These results displayed the simple production strategy of 3D GH-based hybrid hydrogel for high-performance SC.
Imidazole substituted Zinc(ii) phthalocyanines for co-catalyst-free photoelectrochemical and photocatalytic hydrogen evolution: influence of the anchoring group
(Royal Soc Chemistry, 2021) Yuzer, A. Celil; Genc, Eminegul; Kurtay, Gulbin; Yanalak, Gizem; Aslan, Emre; Harputlu, Ersan; Ocakoglu, Kasim
Novel zinc phthalocyanine derivatives, ZnPc-1 and ZnPc-2, consisting of one and four imidazole units, respectively, have been synthesized and utilized as panchromatic photosensitizers for photocatalytic and photoelectrochemical H-2 evolution. The effect of the imidazole-anchoring group on the photocatalytic H-2 production has been compared with ZnPc-3, which possesses a carboxylic acid unit as the anchoring group. ZnPc-1/TiO2 shows the best photoactivity with the highest H-2 evolution rate of 0.4006 mmol g(-1) h(-1), which is much higher than that of ZnPc-2/TiO2 and ZnPc-3/TiO2 (0.3319 mmol g(-1) h(-1) and 0.3555 mmol g(-1) h(-1), respectively). After 20 h of irradiation, ZnPc-1 produces an H-2 production rate of 3.4187 mmol g(-1) with a turnover number (TON) of 14863 and a solar-to-hydrogen energy (STH) conversion efficiency of 1.03%, without using a co-catalyst.
Improvement in performance of g-C3N4 nanosheets blended PES ultrafiltration membranes including biological properties
(Elsevier, 2021) Sert, Buse; Ozay, Yasin; Harputlu, Ersan; Ozdemir, Sadin; Yalcin, M. Serkan; Ocakoglu, Kasim; Dizge, Nadir
This study aims to investigate the modification of polyethersulphone (PES) membrane with graphitic carbon nitride (g-C3N4) nanosheets for improving the antifouling and separation performance. The nanocomposite membranes were fabricated with blending of different g-C3N4 nanosheets (0.50, 1.00, and 2.00 wt%) into PES and they were synthesized by the phase inversion method. The fabricated g-C3N4 nanosheets and composite membranes were analyzed for their morphology. Scanning electron microscopy (SEM) with Energy Dispersive X-Ray Analysis (EDX) mapping were used to detect the distribution of g-C3N4 nanosheets on membrane surface, whereas surface roughness of membrane was evaluated by atomic force microscopy (AFM). The composite membrane surface was found to be hydrophilic (67.54 degrees), while the water flux of the composite membrane was found to be 254.8 L/m(2)/h for 2.00 wt% g-C3N4/PES membrane. The bovine serum albumin (BSA) separation tests indicated that the composite membrane supplied 98.5% BSA rejection ratio. Moreover, a significant improvement in antifouling characteristics were verified from BSA filtration experiments. g-C3N4 was also investigated for some of its biological properties such as antioxidant, antimicrobial, DNA cleavage, biofilm inhibition, and bacterial viability effect. g-C3N4 showed good free radical scavenging activity and moderate chelating activity at 500 mg/L. It was also determined that single-strand DNA cleavage activities occurred at all tested concentrations. g-C3N4 exhibited significant antibiofilm activity and inhibitory effects on E. coli vitality as 90.9%, 97.1%, and 98.9% at 250, 500, and 1000 mg/L, respectively. This study provides a simple and useful guideline to create a UF membrane resistant against organic fouling and expand its practical applications for wastewater treatment.
Improving the Photocatalytic Hydrogen Generation Using Nonaggregated Zinc Phthalocyanines
(Amer Chemical Soc, 2021) Acar, Eminegul Genc; Yuzer, A. Celil; Kurtay, Gulbin; Yanalak, Gizem; Harputlu, Ersan; Aslan, Emre; Ocakoglu, Kasim
In comparison to traditional solar cells, the dye-sensitized photocatalytic system is one of the most appealing artificial photosynthesis mechanisms due to its low cost and straightforward fabrication. Herein, the photoelectrochemical and photocatalytic hydrogen evolution reactions of Zn-based phthalocyanine (Pc) derivatives, abbreviated as ZnPc-1 and ZnPc-2, were primarily studied in the presence of TEOA sacrificial electron donor. To this aim, the PC activities of ZnPc-1/TiO2 and ZnPc-2/TiO2 photocatalysts were investigated in the absence and presence of a cocatalyst. For the first hour, the amount of hydrogen generated by ZnPc derivatives (ZnPc-1/TiO2 and ZnPc-2/TiO2) was determined to be 1.221 and 0.864 mmol g(-1) h(-1), respectively. Additionally, the solar-to-hydrogen conversion efficiencies of ZnPc-1/TiO2 and ZnPc-2/TiO2 were ascertained to be 3.15% and 2.22%, respectively. Interestingly, STH efficiencies of photocatalysts were increased about 4-fold in the presence of a cocatalyst. Consequently, to elucidate the structural properties of ZnPc-1 and ZnPc-2, density functional theory (DFT) and time-dependent DFT studies were also conducted, and it was discovered that noncovalent interactions and steric hindrance effects on ZnPc-2 are tightly related to the experimentally determined PC activity differences between ZnPc-1 and ZnPc-2.
Influence of silane coating and graphene oxide integration on the magnetothermal Behaviors of La1-xSrxMnO3 nanoparticles
(Elsevier, 2025) Sert, Buse; Kaya, Gul; Cicek, Sinem; Harputlu, Ersan; Simsek, Telem; Tekgul, Atakan; Unlu, C. Gokhan
In this study, La1-xSrxMnO3 (x = 0.27, 0.3, 0.33) magnetic nanoparticles (MNPs) were synthesized and then these nanoparticles synthesized in the core-shell structure were coated with silane for potential magnetic hyperthermia applications. In order to provide support material for the coated magnetic nanoparticles, silane-coated hybrid magnetic nanoparticles were obtained by producing graphene oxide (GO) nanoflakes. The structural and magnetic properties and magnetothermal properties of these structures were investigated. It was observed that the structure of the silane-coated magnetic nanoparticles remained intact and did not show any degradation compared to the uncoated materials. In addition, the highest saturation magnetization (MS) value was observed in the sample doped with x = 0.30. This value indicated that the heating power would be higher than the other doped samples in the specific absorption ratio (SAR) measurements. In this context, the heating amount in the silane-coated samples showed a slight decrease compared to the uncoated samples. Despite the decrease in the SAR values of the integrated samples by incorporating GO into the coated MNPs, it is anticipated that effective results will be obtained for practical applications with the advantage of increasing the thermal conductivity of GO.
Investigating the effect of coating and synthesis parameters on La1-xSrxMnO3 based core-shell magnetic nanoparticles
(Elsevier, 2025) Sert, Buse; Kaya, Gul; Tataroglu, Aleyna Akcay; Harputlu, Ersan; Simsek, Telem; Tekguel, Atakan; Unlu, C. Gokhan
Magnetic nanoparticles are an important class of functional materials that have unique magnetic properties due to their reduced size (<100 nm) and have the potential for use in many fields. In the preparation of magnetic nanoparticles, factors such as intrinsic magnetic properties, surface coating, size and shape of the particles, surface charge and stability are very important. In this regard, carefully determining the synthesis parameters of magnetic nanoparticles and particle coating materials is of critical importance in the application area chosen for the material. In this study, La1-xSrxMnO3 (x = 0.27, 0.30, 0.33) magnetic nanoparticles (MNPs), carbon-coated magnetic nanoparticles in core-shell structure (C@MNP) and their derivatives integrated into graphene oxide (GO-C@MNP) were synthesized and their properties were investigated in detail for their use in possible future application studies. The crystal structure of perovskite compounds with Pbnm symmetry remains unchanged after carbon coating but shrinks in volume due to its amorphous structure. The magnetic behavior of the uncoated and coated materials is almost identical, but the Curie temperature of the compounds shifts to a higher temperature. In the specific absorption ratio (SAR) measurements performed, it was found that the best SAR value for carbon-coated MNPs was 12.9 W/g at x = 0.27. By integrating the MNPs into graphene oxide, heat is easily distributed regionally, and this shows that the structures can be ideal candidates for applications such as hyperthermia, drug carriers, tissue repair, and cellular therapy including cell labeling and targeting. Perovskite-structured manganite materials were selected for their suitability in controlled production, where the Curie temperature can be tuned near the therapeutic temperature by adjusting the doping levels, making them ideal for magnetic hyperthermia applications. In this study, for the first time, the nanoparticle surfaces were coated with carbon, which was chosen not only due to carbon's non-magnetic nature but also because it provides an ideal platform for future combined biomedical applications such as drug delivery systems.
Investigation of graphene-coated Ag/AgCl electrode performance in surface electromyography measurement
(Elsevier, 2022) Alcan, Veysel; Harputlu, Ersan; Ünlü, Cumhur Gökhan; Ocakoğlu, Kasım; Zinnuroğlu, Murat
Conventional silver-silver chloride (Ag/AgCl) electrodes are widely used for recording surface electromyography (sEMG) with a conductive gel. However, for long-term sEMG recording, the gel has some disadvantages that cause high impedance. Therefore, the dry electrodes have been alternatively purposed to overcome these disadvantages. Recently, the nanomaterial-based dry electrodes have been developed for long term electrophysiological signal recording. In the present study, we aimed to develop a graphene-coated Ag/AgCl electrode for long-term recording. We transferred single layer graphene (SLG) on the Ag/AgCl electrode surface by using chemical vapor deposition and confirmed this process by Raman scattering spectroscopy and scanning electron microscopy. We then compared the graphene-coated Ag/AgCl and conventional Ag/AgCl electrodes by evaluating median motor nerve conduction studies (mNCS) and their impedance. The charge transfer resistance (Rct) for the Ag/AgCl electrode (4170 ?) was much higher than graphene-coated Ag/AgCl electrode (Rct = 24.6 ?). For median mNCS measurements without gel, the graphene-coated Ag/AgCl electrode provided a better amplitude of distal and proximal compound muscle action potential (28.3 mV and 25.8 mV, respectively) than the Ag/AgCl electrode (21.8 mV and 20.9 mV, respectively). Consequently, the present study suggests promising results in terms of the usability of graphene-coated Ag/AgCl electrodes for long-term monitoring and wearable systems applications of sEMG. In future studies, we aim to investigate clinical applicability of graphene-coated sEMG electrodes that include extended clinical settings and larger study population.
Investigation of in vitro biological activities of hollow mesoporous carbon nanoparticles bearing D-NMAPPD on human lung adenocarcinoma cells
(Elsevier, 2022) Ugur, Naz; Harputlu, Ersan; Sezer, Canan Vejselova; Demirdogen, Ruken Esra; Ince, Mine; Unlu, C. Gokhan; Yurt, Fatma
The uniformly dispersed hollow mesoporous carbon nanoparticles (HMCNPs) were successfully synthesized by hard-template methods, and D-NMAPPD (B13) was successfully loaded onto the nanoparticle surface for the first time. Structural properties of bare and B13 loaded HMCNPs (HMCNs-B-13) were investigated by Fourier Transform Infrared Spectroscopy (FT-IR), Field Emission-Scanning Electron Microscopy (FE-SEM), Thermal Gravimetric Analysis (TG). The amount of drug released was determined via in vitro drug release studies at 37 degrees C in SBF through UV-Vis spectrometric and thermal analyses. TG data revealed that the proportion of loaded B-13 was 33.60%. Their ability to induce apoptosis in cultures of A549 human lung adenocarcinoma cells was investigated, and the inhibitory effect of HMCNPs-B-13 on lung cancer cell proliferation was determined in vitro. The IC50 values determined after application periods of 24 and 48 h were found to be 16.13 mu g/mL and 12.96 mu g/mL, respectively. The role of HMCNPs-B-13 on the morphology and ultrastructure of A549 cells was also investigated by confocal microscopy and Transmission electron microscopy (TEM) studies.
Investigation of the antifouling properties of polyethersulfone ultrafiltration membranes by blending of boron nitride quantum dots
(Elsevier, 2021) Sert, Buse; Gonca, Serpil; Ozay, Yasin; Harputlu, Ersan; Ozdemir, Sadin; Ocakoglu, Kasim; Dizge, Nadir
This study aims to investigate the modification of polyethersulfone (PES) membrane with boron nitride quantum dots (BNQD) for improving the antifouling performance. The composite membranes were synthesized by blending different amounts of BNQD (0.50, 1.00, and 2.00 wt.%) into PES with the non-solvent induced phase separation (NIPS) method. UV-vis absorption, X-ray diffraction (XRD), and transmission electron microscopy (TEM) were used to characterize BNQD. Moreover, porosity, pore size, contact angle, permeability, bovine serum albumin (BSA) rejection, and antifouling properties were determined for composite membranes. The enhanced biological activity of BNQD was investigated based on antioxidant, antimicrobial, anti-biofilm, bacterial viability inhibition, and DNA cleavage studies. The BNQD showed 19.35 % DPPH radical scavenging activity and 76.45 % ferrous ion chelating activity at 500 mg/L. They also exhibited good chemical nuclease activity at all concentrations. BNQD had moderate antibacterial activity against all tested microorganisms. Biofilm inhibition percentage of BNQD was determined as 82.31 % at 500 mg/L. Cell viability assay demonstrated that the BNQD showed strong cell viability inhibition 99.9 % at the concentration of 1000 mg/L. The porosity increased from 56.83 +/- 1.17%-61.83 +/- 1.17 % while BNQD concentration increased from 0 to 2.00 wt%. Moreover, the hydrophilicity of BNQD nanocomposite membranes also increased from 75.42 +/- 0.56 degrees to 65.34 +/- 0.25 degrees. The mean pore radius is far slightly changed from 16.47 +/- 0.35 nm to 19.16 +/- 0.22 nm. The water flux increased from 133.5 +/- 9.5 L/m(2)/h (for pristine membrane) to 388.6 +/- 18.8 L/m(2)/h (for PES/BNQD 2.00 wt% membrane). BSA flux increased from 38.8 +/- 0.9 L/m(2)/h to 63.2 +/- 2.7 L/m(2)/h up to 1.00 wt% amount of BNQD nanoparticles.
Molecular mechanism of direct electron transfer in the robust cytochrome-functionalised graphene nanosystem
(Royal Soc Chemistry, 2021) Jacquet, Margot; Kiliszek, Malgorzata; Osella, Silvio; Izzo, Miriam; Sar, Jaroslaw; Harputlu, Ersan; Unlu, C. Gokhan
Construction of green nanodevices characterised by excellent long-term performance remains high priority in biotechnology and medicine. Tight electronic coupling of proteins to electrodes is essential for efficient direct electron transfer (DET) across the bio-organic interface. Rational modulation of this coupling depends on in-depth understanding of the intricate properties of interfacial DET. Here, we dissect the molecular mechanism of DET in a hybrid nanodevice in which a model electroactive protein, cytochrome c(553) (cyt c(553)), naturally interacting with photosystem I, was interfaced with single layer graphene (SLG) via the conductive self-assembled monolayer (SAM) formed by pyrene-nitrilotriacetic acid (pyr-NTA) molecules chelated to transition metal redox centers. We demonstrate that efficient DET occurs between graphene and cyt c(553) whose kinetics and directionality depends on the metal incorporated into the bio-organic interface: Co enhances the cathodic current from SLG to haem, whereas Ni exerts the opposite effect. QM/MM simulations yield the mechanistic model of interfacial DET based on either tunnelling or hopping of electrons between graphene, pyr-NTA-M2+ SAM and cyt c(553) depending on the metal in SAM. Considerably different electronic configurations were identified for the interfacial metal redox centers: a closed-shell system for Ni and a radical system for the Co with altered occupancy of HOMO/LUMO levels. The feasibility of fine-tuning the electronic properties of the bio-molecular SAM upon incorporation of various metal centers paves the way for the rational design of the optimal molecular interface between abiotic and biotic components of the viable green hybrid devices, e.g. solar cells, optoelectronic nanosystems and solar-to-fuel assemblies.
Nano-cubes for energy storage
(Elsevier Sci Ltd, 2020) Harputlu, Ersan; Gurgen, Seda; Ugur, Naz; Ocakoglu, Kasim
[No abstract available]
Nanoarchitectonics of the supercapacitor performance of LaNiO3 perovskite on the graphitic-C3N4 doped reduced graphene oxide hydrogel
(Elsevier, 2022) Harputlu, Ersan
Designing highly efficient, low-cost hybrid nanostructures with having favorable morphology and excellent conductivity is very promising for electrodes used in electrochemical storage devices. This study shows the synthesis of a new three-dimensional (3D) hybrid structure consisting of lanthanum nickel oxide (LaNiO3) perovskite, graphite carbon nitride (g-C3N4), and reduced graphene oxide hydrogel (RGOH) structures for the new hybrid supercapacitor (SC) application. The 3D hybrid structure, which is a new SC application, draws attention according to the specific capacitance (Cs) result for graphene-based hydrogel structure. For this purpose, while g-C3N4 is selected to plays an important role to increase the electrochemical activity of SC, the LaNiO3 perovskite structure is used to increase the discharge capacity of SC as well as to provide high discharge current and long cycle life. As a result of electrochemical studies, the superior capacitive performance of LaFeO3/ g-C3N4@RGOH showed Cs and unique performance of 750.56 F g(-1) at a current density of 1 A g(-1). The 3D structure is used as anode material for fabricating symmetric two-electrode supercapacitor systems. Moreover, the LaFeO3/g-C3N4@RGOH materials display magnificent cyclic stability of 82% for 5000 cycles at a current density of 10 A g(-1), which claims the new material progress in the energy field.

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