Browsing by Author "Polatoglu, I"
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Item Quantum Dots for Bioelectrochemical ApplicationsPolatoglu, I; Eroglu, E; Aydin, LItem Nanostructured Metal Oxide-Based Electrochemical Biosensors in Medical DiagnosisKeles, G; Ataman, ES; Taskin, SB; Polatoglu, I; Kurbanoglu, SNanostructured metal oxides (NMOs) provide electrical properties such as high surface-to-volume ratio, reaction activity, and good adsorption strength. Furthermore, they serve as a conductive substrate for the immobilization of biomolecules, exhibiting notable biological activity. Capitalizing on these characteristics, they find utility in the development of various electrochemical biosensing devices, elevating the sensitivity and selectivity of such diagnostic platforms. In this review, different types of NMOs, including zinc oxide (ZnO), titanium dioxide (TiO2), iron (II, III) oxide (Fe3O4), nickel oxide (NiO), and copper oxide (CuO); their synthesis methods; and how they can be integrated into biosensors used for medical diagnosis are examined. It also includes a detailed table for the last 10 years covering the morphologies, analysis techniques, analytes, and analytical performances of electrochemical biosensors developed for medical diagnosis.Item A new design strategy with stochastic optimization on the preparation of magnetite cross-linked tyrosinase aggregates (MCLTA)Polatoglu, I; Aydin, LIn this study, a new design strategy with a systematic optimization process is proposed for the preparation of magnetite cross-linked tyrosinase aggregates (MCLTA) by using the concentration of magnetite nanoparticle, glutaraldehyde and tyrosinase enzyme as design variables. A comprehensive study on multiple non-linear neuroregression analysis has been performed as a compelling alternative to the insufficient approaches on modelingdesign-optimization of MCLTA. For this aim, the experimental process has been modeled with 13 candidate functional structures by using a hybrid method to test the accuracy of their predictions. R-training(2), R-testing(2) values, and boundedness of the functions have been checked to reveal the realistic ones. Then four different design approaches in terms of three distinct scenarios have been used to optimize the process. The results show that, all models define the process well, depending on R-training(2). However, only five and nine models are appropriate based on R-testing(2) for the first use activity and residual activity, respectively. On the other hand, depending on to be a realistic value, model TON best describes the first use activity, while the best one is FONT for residual activity. It is also concluded that the scenario types and selection of constraints for design variables affect the optimization results.Item A Novel Approach for the Optimal Design of a BiosensorPolatoglu, I; Aydin, L; Nevruz, BÇ; Özer, SA novel design optimization strategy is proposed to enhance the analytical performance of a biosensor by taking into consideration the constructional and experimental parameters as design variables. A detailed study on multiple nonlinear neuro-regression analysis has been performed methodically in order to overcome the insufficient approaches on modeling-design-optimization of a biosensor. For this aim, the data were selected from a literature study. A hybrid method is used to test the accuracy of the predictions of 12 candidate functional structures that were proposed for modeling the data. The boundedness of the candidate models is checked after the calculation of R-training(2) and R-testing(2) values to reveal whether the model is realistic or not. Then appropriate models were optimized by using the four different optimization algorithms in terms of three different optimization scenarios. The results show that all the models express the process well regarding R-training(2). However, only four models are appropriate based on R-testing(2), and two of them were selected as the objective function depending on to be a realistic value. This novel optimization approach is also feasible for another modeling-design-optimization problem in analytical applications.Item COVID-19 in early 2023: Structure, replication mechanism, variants of SARS-CoV-2, diagnostic tests, and vaccine & drug development studiesPolatoglu, I; Oncu-Oner, T; Dalman, I; Ozdogan, SCoronavirus Disease-19 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome-coronaviruses-2 (SARS-CoV-2), a highly pathogenic and transmissible coronavirus. Most cases of COVID-19 have mild to moderate symptoms, including cough, fever, myalgias, and headache. On the other hand, this coronavirus can lead to severe complications and death in some cases. Therefore, vaccination is the most effective tool to prevent and eradicate COVID-19 disease. Also, rapid and effective diagnostic tests are critical in identifying cases of COVID-19. The COVID-19 pandemic has a dynamic structure on the agenda and contains up-to-date developments. This article has comprehensively discussed the most up-to-date pandemic situation since it first appeared. For the first time, not only the structure, replication mechanism, and variants of SARS-CoV-2 (Alpha, Beta, Gamma, Omicron, Delta, Epsilon, Kappa, Mu, Eta, Zeta, Theta, lota, Lambda) but also all the details of the pandemic, such as how it came out, how it spread, current cases, what precautions should be taken, prevention strategies, the vaccines produced, the tests developed, and the drugs used are reviewed in every aspect. Herein, the comparison of diagnostic tests for SARS-CoV-2 in terms of procedure, accuracy, cost, and time has been presented. The mechanism, safety, efficacy, and effectiveness of COVID-19 vaccines against SARS-CoV-2 variants have been evaluated. Drug studies, therapeutic targets, various immunomodulators, and antiviral molecules applied to patients with COVID-19 have been reviewed.Item An overview of biomolecules, immobilization methods and support materials of biosensorsAsal, M; Özen, Ö; Sahinler, M; Baysal, HT; Polatoglu, IPurpose Traditional analytical methods are often time-consuming and require bulky instruments, making their widespread implementation challenging. This paper aims to represent the principal concepts of biosensors as an introduction of this technology to readers and offers a comprehensive understanding of its functions. Design/methodology/approach The authors provide descriptions of the components, characteristics and advantages of biosensors along with the immobilization methods, followed by a brief discussion. Findings A biosensor is an analytical device comprising a specific biomolecule and a transducer in conjunction with an output system. The biomolecule recognizes a specific target which leads to a change in physicochemical properties of a system. This biorecognition phenomenon is later converted into a detectable signal by the transducer. Biosensors can essentially serve as rapid and cost-effective devices with excellent sensitivity and specificity for critical purposes in innumerable fields, ranging from scientific research to day-to-day applications. Originality/value Here, the authors explain and discuss the approaches and challenges with the aim of leading to an interest in biosensor development and improving their applications.Item Recent Developments in Enzyme, DNA and Immuno-Based BiosensorsAsal, M; Özen, Ö; Sahinler, M; Polatoglu, INovel sensitive, rapid and economical biosensors are being developed in a wide range of medical environmental and food applications. In this paper, we review some of the main advances in the field over the past few years by discussing recent studies from literature. A biosensor, which is defined as an analytical device consisting of a biomolecule, a transducer and an output system, can be categorized according to the type of the incorporated biomolecule. The biomolecules can be enzymes, antibodies, ssDNA, organelles, cells etc. The main biosensor categories classified according to the biomolecules are enzymatic biosensors, immunosensors and DNA-based biosensors. These sensors can measure analytes produced or reduced during reactions at lower costs compared to the conventional detection techniques. Numerous types of biosensor studies conducted over the last decade have been explored here to reveal their key applications in medical, environmental and food industries which provide comprehensive perspective to the readers. Overviews of the working principles and applications of the reviewed sensors are also summarized.Item Development of an optical tyrosinase biosensor (TCA) for detection of Parathion-MethylPolatoglu, I; Ozkan, FCPurpose This paper aims to present a novel and cost-effective optical biosensor design by simple preparation method for detection of parathion-methyl, which is a model pesticide pose to public health and the environment. Design/methodology/approach The optical enzyme biosensor (TCA) for detection of pesticide parathion-methyl was developed on the basis of immobilization of tyrosinase enzyme on chitosan film by adsorption technique. The analytic performance of TCA was investigated by measuring its activity with Ultraviolet (UV) visible spectrophotometer. Findings Uniform porous network structure and protonated groups of chitosan film provided a microenvironment for tyrosinase immobilization evident from Fourier transform infrared (FTIR) spectroscopy and Atomic Force Microscopy analysis. TCA has a wide linear detection range (0-1.03 mu M) with high correlation coefficient and it can detect the parathion-methyl concentration as low as 159 nM by noncompetitive inhibition kinetics. Using the TCA sensor both for ten times and at least 45 days without a significant loss in its activity are the indicators of its good operational and storage stability. Moreover, TCA can be applicable to tap water, providing a promising tool for pesticides detection. Originality/value This is the first time to use the in situ analytical technique that can improve the performance of optical enzyme sensor provided to control the pesticide residue better with respect to traditional techniques. The effect of organic solvents on the performance of optical enzyme biosensor was investigated. Inhibition kinetic of the solvents rarely encountered in literature was also studied besides the pH and temperature tolerance of the optical biosensor.Item A new hybrid approach in selection of optimum establishment location of the biogas energy production plantCeylan, AB; Aydin, L; Nil, M; Mamur, H; Polatoglu, I; Sözen, HIn this study, a new hybrid modeling optimization approach is presented for choosing the best installation location of a biogas power plant. This approach was evaluated in a case study for Manisa province in Turkey. First, the animal waste potential in Manisa was determined. By examining the biogas potential in Manisa, the mathematical model of the process is identified with the neuro-regression approach. Comparisons were made with the traditional and hybrid models, and it was seen that the values of the hybrid model based on the introduced approach were at more acceptable levels. Depending on this model, the most appropriate district where the power plant can be installed was calculated by considering the potentials in the environment. The single-objective and multi-objective approaches were considered to acquire the optimum design for the system. The modified versions of the optimization methods differential evolution (MDE), Nelder-Mead (MNM), simulated annealing (MSA), and random search (MRS) algorithms were used to solve problems. Thanks to the calculations and optimizations, it was concluded that it would be more appropriate to establish a biogas plant around Golmarmara, Salihli, and Ahmetli triangle in Manisa. It was determined that when this installation takes place, 68 GWh of electrical energy can be produced annually. This study is a pioneering study for the installation locations of bioenergy power plants in terms of the methods and approaches.Item Modeling of molecular interaction between catechol and tyrosinase by DFTPolatoglu, I; Karatas, DIn this study, the synthetic active site model of tyrosinase enzyme's (His(3))(CuOHCu)-O-center dot center dot-Cu-center dot center dot(His(3)) arrangement is constituted by applying the density functional theory (DFT) to reveal the enzymatic conversion of catechol in molecular basis. This is the first time the binding mechanisms of catechol in relation to the enzyme active site (met-tyrosinase) in a vacuum environment, explicit water, and solvent (ethanol, acetone)/water mixture have been studied using the DFT. The theoretical results are supported along with the experimental ones to clarify the structure-activity relationship in these models. As understood from the mechanisms, the initial H abstraction from catechol is the most probable rate-limiting step. The parameters that cause the copper region to become congested or comfortable for H abstraction, such as the ordered structure of water molecules, Cu-Cu distance, H-bond distance, orientation and conformation of histidine residues around the copper center, and electrostatic potential of the system, play a significant role in the catechol/met-tyrosinase interaction. (C) 2019 Elsevier B.V. All rights reserved.Item Electrochemical Sensing Platform Based on Tyrosinase Immobilized Magnetite Chitosan Nanobiocomposite Film and Its Application as Catechol BiosensorPolatoglu, IThe easy design of an enzyme electrode using tyrosinase immobilized magnetite chitosan nanobiocomposite film (TMCG) and its applicability for electrochemical sensing platform are reported in this work. The sensor components were characterized by scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). Stable biomaterial was obtained by chemical immobilization of the enzyme to chitosan structure with glutaraldehyde. Magnetite nanoparticles were homogeneously distributed on the chitosan surface. Nyquist curves revealed that, chitosan and tyrosinase enzyme exhibit higher resistance to the electron transfer while magnetite nanoparticles promote the electron transfer as a result of their nanostructure behaviors. In addition to well defined oxidation peak, new reduction peak was observed from CV analysis after magnetite modification as a result of electrochemical reduction of enzymatically produced o-quinone to the catechol. The developed biosensor (TMCG*) selectively detected the catechol at a sensitivity of 0.057A/M in a linear range from 1 mu M to 30 mu M with a detection limit of 260 nM and K-m value of 22.5 mu M. These findings strongly indicate that TMCG* is applicable as an electrochemical sensing platform for detection of the sample that inhibits the tyrosinase enzyme in tap water. (c) 2019 The Electrochemical Society.Item Determination of effective assay parameters on the activity of magnetite cross-linked invertase aggregates by personal glucose meterPolatoglu, I; Yardim, AThe invertase enzyme has been immobilized onto various support materials to enhance operational stability, shelf life, and reusability compared to free ones. Among the immobilization methods, carrier-free immobilization, such as cross-linked enzyme aggregates (CLEAs), attracts attention. However, recovery of the CLEAs from the reaction environment by centrifugation or filtration is a great challenge. The use of magnetic nanoparticles (Fe3O4) can overcome these separation limitations of the aggregates. For this aim, in this study, the surface of magnetite nanoparticles was functionalized with a significant number of free amino groups through silanization reaction. After precipitation of these aggregates and then cross-linking to the functionalized structure, the resulting magnetite cross-linked invertase aggregates (MCLIAs) were obtained, having different enzyme and glutaraldehyde concentrations. Magnetic nanoparticles were characterized by SEM, VSM, and FTIR analysis. The assay parameters, both constructional and experimental ones on the activity of MCLIAs, were practically determined by a personal glucose meter (PGM). The results indicate that magnetite nanoparticles with superparamagnetic behaviour were successfully functionalized with amino groups. The activity results demonstrated that experimental parameters were more effective than constructional parameters. MCLIAs also exhibited maximum activity at pH 5. Furthermore, 30-min incubation time and 35 degrees C were the best activity assay conditions.Item Methyl cellulose/okra mucilage composite films, functionalized with Hypericum perforatum oil and gentamicin, as a potential wound dressingCoban, SN; Polatoglu, I; Eroglu, EThere is a growing demand for the development of functional wound dressings enriched with bioactive natural compounds to improve the quality of life of the population by accelerating the healing process of chronic wounds. In this regard, a functional composite film of okra mucilage (OM) and methylcellulose (MC) incorporated with Hypericum perforatum oil (Hp) and gentamicin (G) was prepared and characterized as a wound dressing. Increasing Hp resulted in improved film properties with a more porous structure, higher WVTR, and lower surface hydrophobicity. Furthermore, incorporating Hp into OM:MC films led to increased elongation at the break while reducing the tensile strength of the films. The highest values of total antioxidant capacity (1.09-1.16 mM trolox equivalent) and total phenolic content (13.76-16.94 mu g GA equivalent mL-1) were measured in the composite films containing the highest Hp concentration (1.5 %). In addition, OM:MC/HpG composite films exhibited significant antibacterial activity against both E. coli and S. aureus and prevented the transmission of these bacteria through the films. Hp incorporation reduced the cytotoxic effects of OM:MC films on BJ cells and increased the wound closure rate in vitro. In conclusion, the developed OM:MC/HpG composite film can be a promising candidate as a novel wound dressing with its superior properties.Item Portable quantification of silver ion by using personal glucose meter (PGM) and magnetite cross-linked invertase aggregates (MCLIA)Polatoglu, I; Yardim, AHeavy metal detection is critical due to its harmful effects on human health and the ecosystem. Enzyme-based platforms attract attention for heavy metal detection such as silver, a toxic metal, due to being small, portable, and requiring only essential equipment compared with the basic analytical methods. In this study, magnetic cross-linked invertase aggregates (MCLIA) were developed for the first time as an enzyme-based signaling platform to detect Ag+ using a personal glucose meter (PGM). EDX, FTIR, and VSM results depicted that MCLIA was successfully developed and exhibits super-paramagnetism. In addition, MCLIA selectively detected the Ag+ at a sensitivity of 1.2 inhibition rate/mu M in a linear range from 5 to 70 mu M with a detection limit of 4.6 mu M and IC50 value of 42.3 mu M. These findings strongly indicate that MCLIA is applicable as a signal platform for portable quantification of other analytes that inhibits the invertase enzyme.Item Synthesis of Novel Phenanthroimidazole Based Beta-Diketone Compounds: Investigation of Their Spectroscopic Properties and Electrochemical CharacterizationGülle, S; Erbas, SÇ; Polatoglu, IIn this study, three new phenanthroimidazole based beta-biketone compounds containing different donor (methoxy and dodecyloxy) and acceptor (cyano) groups were synthesized. Spectroscopic and electrochemical properties of the synthesized compounds were studied. FTIR, 1H-NMR, 13C-NMR, and LC-MS/MS were carried out for the structural analyses of the phenanthroimidazole derivatives. UV-vis absorption and emission studies were also carried out in the solvents with different polarities. High molar absorption coefficients and high Stokes' shift values were observed. The photostability of these derivatives was measured in all the solvents used. These values suggest that the derivatives could be used in fluorescence imaging applications for various biological and analytical purposes. Furthermore, the potential use of these molecules as electron transfer mediators for the electrochemical behavior of biological material was investigated. All the curves were also simulated using the most suitable equivalent Randles circuit. The charge-transfer resistance values varied depending on the donor and acceptor groups in the synthesized molecules. The Nyquist plots were evaluated, and it was observed that these molecules exhibit different resistance to electron transfer. These synthesized molecules can potentially be used as electron transfer mediators in the electrochemical detection of biological analytes.