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Öğe Biomarker Detection in Early Diagnosis of Cancer: Recent Achievements in Point-of-Care Devices Based on Paper Microfluidics(MDPI, 2023) Erkocyigit, Bilge Asci; Ozufuklar, Ozge; Yardim, Aysenur; Celik, Emine Guler; Timur, SunaMicrofluidics is very crucial in lab-on-a-chip systems for carrying out operations in a large-scale laboratory environment on a single chip. Microfluidic systems are miniaturized devices in which the fluid behavior and control can be manipulated on a small platform, with surface forces on the platform being greater than volumetric forces depending on the test method used. In recent years, paper-based microfluidic analytical devices (mu PADs) have been developed to be used in point-of-care (POC) technologies. mu PADs have numerous advantages, including ease of use, low cost, capillary action liquid transfer without the need for power, the ability to store reagents in active form in the fiber network, and the capability to perform multiple tests using various measurement techniques. These benefits are critical in the advancement of paper-based microfluidics in the fields of disease diagnosis, drug application, and environment and food safety. Cancer is one of the most critical diseases for early detection all around the world. Detecting cancer-specific biomarkers provides significant data for both early diagnosis and controlling the disease progression. mu PADs for cancer biomarker detection hold great promise for improving cure rates, quality of life, and minimizing treatment costs. Although various types of bioanalytical platforms are available for the detection of cancer biomarkers, there are limited studies and critical reviews on paper-based microfluidic platforms in the literature. Hence, this article aims to draw attention to these gaps in the literature as well as the features that future platforms should have.Öğe Design of Polymeric Surfaces as Platforms for Streamlined Cancer Diagnostics in Liquid Biopsies(MDPI, 2023) Ghorbanizamani, Faezeh; Moulahoum, Hichem; Celik, Emine Guler; Zihnioglu, Figen; Beduk, Tutku; Goksel, Tuncay; Turhan, KutsalMinimally invasive approaches for cancer diagnosis are an integral step in the quest to improve cancer survival. Liquid biopsies such as blood samples are matrices explored to extract valuable information about the tumor and its state through various indicators, such as proteins, peptides, tumor DNA, or circulating tumor cells. Although these markers are scarce, making their isolation and detection in complex matrices challenging, the development in polymer chemistry producing interesting structures, including molecularly imprinted polymers, branched polymers, nanopolymer composites, and hybrids, allowed the development of enhanced platforms with impressive performance for liquid biopsies analysis. This review describes the latest advances and developments in polymer synthesis and their application for minimally invasive cancer diagnosis. The polymer structures improve the operational performances of biosensors through various processes, such as increased affinity for enhanced sensitivity, improved binding, and avoidance of non-specific interactions for enhanced specificity. Furthermore, polymer-based materials can be a tremendous help in signal amplification of usually low-concentrated targets in the sample. The pros and cons of these materials, how the synthesis process affects their performance, and the device applications for liquid biopsies diagnosis will be critically reviewed to show the essentiality of this technology in oncology and clinical biomedicine.Öğe A Functional Platform for the Detection of JWH-073 as a Model for Synthetic Cannabinoids(Wiley-V C H Verlag Gmbh, 2018) Sengel, Tulay Yilmaz; Celik, Emine Guler; Aydogan, Cansu; Gumus, Zinar Pinar; Ilktac, Raif; Aydindogan, Eda; Ciftci, Mustafa; Aldemir, Ebru; Coskunol, Hakan; Timur, Suna; Yagci, YusufDuring the last decade, progress has been made in the on-site detection of abused drug use. Herein, we present an electrochemical biosensor for the detection of one of the synthetic cannabinoids (SCs), JWH-073, using poly (methyl methacrylate) (PMMA) hyperbranched copolymer (HBC) as a base coating and antibody molecules to bind the JWH-073 to the surface. Modification of the surface is proved with various techniques such as differential pulse voltammetry, cyclic voltammetry, and electrochemical impedance spectrometry. The limit of detection and linearity (in logarithmic scale) for JWH-073 were found to be 31.87 ng/mL and 25-500 ng/mL, respectively. The selectivity of the proposed biosensor was also tested in the presence of interfering molecules and the response was much higher for JWH-073 in all measurements. In the final part of the study, synthetic urine was tested with the device and the relative standard deviation value was calculated to be less than 5.0%. The confirmation of data from the resulting bio-platform was performed via LC-QTOF/MS. This work is the first of its kind, a novel, rapid, cost-effective sensing platform for the detection of the SC.Öğe Ionic liquid-hydrogel hybrid material for enhanced electron transfer and sensitivity towards electrochemical detection of methamphetamine(Elsevier, 2022) Ghorbanizamani, Faezeh; Moulahoum, Hichem; Celik, Emine Guler; Timur, SunaReliable onsite biosensors for detecting drugs of abuse are of critical importance for the current society. Electrochemical sensors, especially screen-printed electrode (SPE)-based sensors, are a strong candidate for onsite drug detection. Although many SPE-based sensors are being developed, enhancing these tools' sensitivity and analytical capacity is a continuous endeavor. Here, we propose a novel approach for SPE surface modification using a combination of hydrogel, ionic liquid, and specific antibodies to detect methamphetamine in human saliva samples. The hydrogel-ionic liquid (ionogel) was synthesized from gelatin, PEG, and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide. FTIR and SEM were used to characterize the material before it was applied over a screen-printed gold electrode for electrochemical measurements using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). After optimization, the calibration of the proposed sensor showed a detection range between 5.0 and 1000 ng/mL with a LOD = 0.56 ng/mL in PBS. Application of the sensor with spiked human saliva demonstrated enhanced sensitivity with a LOD = 0.72 ng/mL. The repeatability and reproducibility of the proposed biosensor demonstrated a coefficient of variance (CV%) reaching 6.92% and 2.53%, respectively. The biosensor showed a high specificity toward methamphetamine compared to other interferents. The current ionogel-based electrochemical immunosensor offers a promising and versatile tool for sensitive onsite detection of substance abuse. (C) 2022 Elsevier B.V. All rights reserved.Öğe Ionic liquids enhancement of hydrogels and impact on biosensing applications(Elsevier, 2022) Ghorbanizamani, Faezeh; Moulahoum, Hichem; Celik, Emine Guler; Timur, SunaThe pursuit of novel materials to enhance specific features and the analytical efficiency of sensors is a hot topic in the biomaterial engineering field. Hydrogels are an important material category that has a good value in biosensing applications due to their immobilization and protection capabilities that enhance their biocompatibility. Progress in development allowed the production of intelligent hydrogel materials that can function as a stimuli-responsive medium in sensing signal actuation. A novel concept in hydrogel-enabled biosensing development is the addition of ionic liquids (ILs) to create unique structures called ionic gels that possess both the intrinsic features of hydrogels and ILs. The current review is a straightforward overview of the two materials (hydrogels and ion gels) with a strong interest in their potential in biosensing applications. A highlight of the most recent and impactful research is analyzed to provide a solid standing reference point for future development.(c) 2022 Elsevier B.V. All rights reserved.Öğe Magnetic Nanofiber Layers as a Functional Surface for Biomolecule Immobilization and One-Use 'Sensing in-a-Drop' Applications(Wiley-V C H Verlag Gmbh, 2018) Sanli, Serdar; Celik, Emine Guler; Demir, Bilal; Gumus, Z. Pinar; Ilktac, Raif; Aksuner, Nur; Demirkol, Dilek Odaci; Timur, SunaStabilization of biomolecules on matrices is critically important. Here we constructed composite nanofibers with magnetic features by electro-spinning of magnetic nanoparticles (MNP) in an appropriate polymer matrix on a collector surface for multiple uses. 'Poly(vinylalcohol)-polyethyleneimine/Fe3O4 magnetic nanoparticles' (PVA-PEI/MNP) composite nanofiber was used on the screen printed electrodes (SPE) to serve as a platform for the glucose oxidase (GOx) biofilm as the model biomolecule. To show the potential application of this material as a biosensor component, the resulted biofilm, called 'PVA-PEI/MNP/GOx', was fixed on SPE via a neodymium magnet for the electrochemical detection of glucose at -0.7 V where oxygen consumption due to enzymatic reaction was measured. The main advantage of the obtained magnetic biomembrane is that it allows analysis with a single drop. After step-by-step surface modifications, analytical characterization was performed using various techniques, such as voltammetry, electrochemical impedance spectroscopy, Fourier-transform infrared spectroscopy and X-Ray photoelectron spectroscopy as well as microscopic techniques. The linear range of the PVA-PEI/MNP/GOx surface was found as 0.0125 to 0.5 mM with a limit of detection of 11.5 mu M for glucose as analyte. The application of PVA-PEI/MNP/GOx for glucose detection in synthetic samples was carried out. Data proved the potential use of the 'PVA-PEI/MNP' surface as a biomolecule immobilization platform for disposable biosensor applications.Öğe Material Design in Implantable Biosensors toward Future Personalized Diagnostics and Treatments(MDPI, 2023) Ghorbanizamani, Faezeh; Moulahoum, Hichem; Celik, Emine Guler; Timur, SunaThe growing demand for personalized treatments and the constant observation of vital signs for extended periods could positively solve the problematic concerns associated with the necessity for patient control and hospitalization. The impressive development in biosensing devices has led to the creation of man-made implantable devices that are temporarily or permanently introduced into the human body, and thus, diminishing the pain and discomfort of the person. Despite all promising achievements in this field, there are some critical challenges to preserve reliable functionality in the complex environment of the human body over time. Biosensors in the in vivo environment are required to have specific features, including biocompatibility (minimal immune response or biofouling), biodegradability, reliability, high accuracy, and miniaturization (flexible, stretchable, lightweight, and ultra-thin). However, the performance of implantable biosensors is limited by body responses and insufficient power supplies (due to minimized batteries/electronics and data transmission without wires). In addition, the current processes and developments in the implantable biosensors field will open new routes in biomedicine and diagnostic systems that monitor occurrences happening inside the body in a certain period. This topical paper aims to give an overview of the state-of-the-art implantable biosensors and their design methods. It also discusses the latest developments in material science, including nanomaterials, hydrogel, hydrophilic, biomimetic, and other polymeric materials to overcome failures in implantable biosensors' reliability. Lastly, we discuss the main challenges faced and future research prospects toward the development of dependable implantable biosensors.Öğe Multiplexed aptasensor for detection of acute myocardial infraction (AMI) biomarkers(Royal Soc Chemistry, 2024) Beduk, Duygu; Beduk, Tutku; Lahcen, Abdellatif Ait; Mani, Veerappan; Celik, Emine Guler; Iskenderoglu, Gamze; Demirci, FerhatAcute myocardial infarction (AMI) is a leading global cause of death. Diagnosis is challenging as cardiac biomarkers are only detectable for a few hours after AMI onset, and current methods are time-consuming and lack selectivity. Therefore, multiple immunological test systems have great importance for rapid and accurate diagnosis. In this context, we developed a rapid immunodiagnostic sensor platform for simultaneous electrochemical detection of cardiac troponin T (cTnT), troponin I (cTnI), and C-reactive protein (CRP) using nanostructured gold-modified laser-scribed graphene (LSG). Aptamer sensors were integrated into the LSG platform for selective AMI biomarkers sensing. Clinical validation was performed on biomarkers from blood samples of 51 AMI patients and 9 healthy controls. Limits of detection were 1.65 ng mL-1 cTnT, 2.58 ng mL-1 cTnI, and 1.84 ng mL-1 CRP. The analytical results determined by the developed platform were compared with the routine standard values of the same patients to prove the accuracy of aptasensors. Sensor results agreed well with standard laboratory assays, highlighting the accuracy of the test platform. The cTnT, cTnI and CRP multiplexed sensor platform demonstrates excellent performance for rapid and sensitive AMI screening. Schematic illustration of the developed aptasensor for multiplex detection of AMI biomarkers.Öğe Paper-Based Analytical Methods for Smartphone Sensing with Functional Nanoparticles: Bridges from Smart Surfaces to Global Health(Amer Chemical Soc, 2018) Aydindogan, Eda; Celik, Emine Guler; Timur, SunaÖğe Papertronics: Marriage between Paper and Electronics Becoming a Real Scenario in Resource-Limited Settings(Amer Chemical Soc, 2023) Hasan, Mohd Rahil; Sharma, Pradakshina; Suleman, Shariq; Mukherjee, Shouvik; Celik, Emine Guler; Timur, Suna; Pilloton, RobertoIntegrating electronic applications with paper, placed next to or below printed images or graphics, can further expand the possible uses of paper substrates. Consuming paper as a substrate in the field of electronics can lead to significant innovations toward papertronics applications as paper comprises various advantages like being disposable, inexpensive, biodegradable, easy to handle, simple to use, and easily available. All of these advantages will definitely spur the advancement of the electronics field, but unfortunately, putting electronics on paper is not an easy task because, compared to plastics, the paper surface is not just rough but also porous. For example, in the case of lateral flow assay testing the sensor response is delayed if the pore size of the paper is enormous. This might be a disadvantage for most electrical devices printed directly on paper. Still, some methods make it compatible when fit with a rough, absorbent surface of the paper. Building electronic devices on a standard paper substrate have sparked much interest because of its lightweight, environmental friendliness, minimal cost, and simple fabrication. A slew of improvements have been achieved in recent years to make paper electronics perform better in various applications, including transistors, batteries, and displays. In addition, flexible electronics have gained much interest in human-machine interaction and wireless sensing. This review briefly examines the origins and fabrication of paper electronics and then moves on to applications and exciting possible paths for paper-based electronics.Öğe Preparation of glutathione loaded nanoemulsions and testing of hepatoprotective activity on THLE-2 cells(Scientific Technical Research Council Turkey-Tubitak, 2021) Yesiltepe, Ozan; Celik, Emine Guler; Geyik, Caner; Gumus, Zinar Pinar; Demirkol, Dilek Odaci; Coskunol, Hakan; Timur, SunaTo improve bioavailability and stability of hydrophobic and hydrophilic compounds, nanoemulsions are good alternatives as delivery systems because of their nontoxic and nonirritant nature. Glutathione (GSH) suffers from low stability in water, where its encapsulation in nanoemulsions is a powerful strategy to its stability in aqueous systems. The aim of this study was to obtain nanoemulsions from the hydrophobic/hydrophilic contents of N. sativa seed oil so as to improve GSH stability along with bioavailability of N. sativa seed oil. Then, the prepared nanoemulsions were tested for in vitro hepatoprotective activity against ethanol toxicity. To the best of our knowledge, there is no study on the test of nanoemulsions by the combination of Nigella sativa seed oils and GSH in hepatoprotective activity. Here, nanoemulsions with different contents were prepared using Nigella sativa seed oils. Content analyses and characterisation studies of prepared nanoemulsions were carried out. In order to investigate the protective effects against to ethanol exposure, THLE-2 cells were pretreated with nanoemulsions for 2 h with the maximum benign dose (0.5 mg/mL of nanoemulsions). Ethanol (400 mM) was introduced to pretreated cells and nontreated cells for 48- or 72-h periods, followed by cell viability assay was carried out. Fluorescence microscopy tests revealed the introduction of the nanoemulsions into THLE-2 cells. The findings show that nanoformulations have promising in vitro hepatoprotective effects on the THLE-2 cell line against ethanol exposure.Öğe Smartphone-Based Multiplexed Biosensing Tools for Health Monitoring(Mdpi, 2022) Beduk, Tutku; Beduk, Duygu; Hasan, Mohd Rahil; Celik, Emine Guler; Kosel, Jurgen; Narang, Jagriti; Salama, Khaled NabilMany emerging technologies have the potential to improve health care by providing more personalized approaches or early diagnostic methods. In this review, we cover smartphone-based multiplexed sensors as affordable and portable sensing platforms for point-of-care devices. Multiplexing has been gaining attention recently for clinical diagnosis considering certain diseases require analysis of complex biological networks instead of single-marker analysis. Smartphones offer tremendous possibilities for on-site detection analysis due to their portability, high accessibility, fast sample processing, and robust imaging capabilities. Straightforward digital analysis and convenient user interfaces support networked health care systems and individualized health monitoring. Detailed biomarker profiling provides fast and accurate analysis for disease diagnosis for limited sample volume collection. Here, multiplexed smartphone-based assays with optical and electrochemical components are covered. Possible wireless or wired communication actuators and portable and wearable sensing integration for various sensing applications are discussed. The crucial features and the weaknesses of these devices are critically evaluated.Öğe Surface Modification with a Catechol-Bearing Polypeptide and Sensing Applications(Amer Chemical Soc, 2018) Aydindogan, Eda; Celik, Emine Guler; Demirkol, Dilek Odaci; Yamada, Shuhei; Endo, Takeshi; Timur, Suna; Yagci, YusufA novel catechol-bearing polypeptide (CtP) was synthesized and used as a component of electrochemical biosensor involving both enzymatic activity and affinity-based sensing systems. Glucose oxidase (GOx) and anti-immunoglobulin G (Anti-IgG) were selected as model biorecognition elements for the selective analysis of glucose and IgG. Step-by-step surface modifications were followed using various techniques such as cyclic voltammetry (CV) and electrochemical impedance spectrometry (EIS) as well as X-ray photoelectron spectroscopy (XPS). Additionally, contact angles were measured in order to observe surface properties. Amperometric measurements using the GOx biosensor were performed at -0.7 V by following the oxygen consumption due to the enzymatic reaction in different glucose concentrations. Affinity-based interactions via IgG sensor were monitored using the differential pulse voltammetry (DPV) technique. As the "surface design with CtP" approach employed herein is generally applicable and easily adaptable to obtain functional matrices for biomolecule immobilization, CtP-coated surfaces can be promising platforms for the fabrication of various biobased sensing systems.Öğe Ultrasensitive covalently-linked Aptasensor for cocaine detection based on electrolytes-induced repulsion/attraction of colloids(Springer, 2020) Sanli, Serdar; Moulahoum, Hichem; Ghorbanizamani, Faezeh; Celik, Emine Guler; Timur, SunaA quick and easy colorimetric sensor based on gold nanoparticles (GNPs) and aptamers for the detection of cocaine was developed. the sensor was named as 'GAPTA' and showed extremely interesting results regarding cocaine detection with a sensitivity to doses of 0.2 nM. the experimental approach consisted of creating a conjugate between GNPs (10 nm size) and aptamers as a sensing base with the addition of an electrolyte (NaCl) that plays the role of aggregation inducer. in the absence of the aptamer, the electrolyte was able to induce aggregation of the GNPs turning the color of the solution from red to blue while the presence of the aptamer is able to hinder the charges attraction and protects the GNPs from aggregating. the optimization of the aptamer and electrolyte concentration was determined to be 118 nM and 55 mM, respectively, and the resultant GAPTA sensor had a detection limit of 0.97 nM. Furthermore, the selectivity of the platform was tested in the presence of different interferents and showed a specific response towards cocaine while interference ranged between 20 and 40%. the applicability of the GAPTA biosensor was tested on synthetic saliva and demonstrated a sensitivity range between 0.2 and 25 nM. These results suggest the potential of the current colorimetric sensor in abuse drugs screening and creates a stable base for new routine platforms for biomedical and toxicology applications. Graphical abstract
