Organo-Fonksiyonel Silan ile Modifiye Edilmiş ITO Elektrot Temelli CDH 22 Biyobelirteç Tespiti için Hassas ve Etiketsiz Bir Elektrokimyasal İmpedans İmmünosensörü

In this work, a novel electrochemical label free immunosensor was fabricated for Cadherin-like protein 22 (CDH 22) biomarker detection based on specific immunoreaction between anti-CDH 22 antibody and CDH 22 antigen. The developedimmunosensor was constructed through the immobilization of anti-CDH 22 antibodies on 3-cyanopropyltrimethoxysilane (CPTMS) modified ITO substrate. The effective binding of the anti-CDH 22 antibodies on the CPTMS silanization agentwas investigated by using morphological characterization (Scanning Electron Microscopy (SEM), Atomic Force Microscopy(AFM)) and electrochemical characterization (Electrochemical Impedance Spectroscopy (EIS), Cyclic Voltammetry (CV)).Under optimum experimental conditions, the ITO/CPTMS modified electrode was a good linker for anti-CDH 22 antibodyanchoring. In addition, CPTMS modified electrode offered an efficient surface to CDH 22 antigen detection. The immunosensor had a wide linear detection range (0.03-3 pg/mL) with low detection limit (9 fg/mL). Also, it had good reproducibility,excellent repeatability and long storage stability. In addition, the practical applicability of the proposed immunosensor wasinvestigated by utilizing human serum samples. The human serum samples recovery results (99.16% - 101.94%) illustratedthe accuracy of the suggested biosensor. Consequently, CPTMS can be a promising platform for biosensor construction andthis suggested immunosensor can be applicable for real human serum analysis.Bu çalışmada, anti-CDH 22 antikoru ve CDH 22 antijeni arasındaki spesifik immüno-reaksiyona dayanan, kadherin benzeri protein (CDH 22) biyobelirtecinin tespiti için yeni bir elektrokimyasal etiketsiz immünosensör üretilmiştir. Geliştirilen immünosensör, anti-CDH 22 antikorlarının 3-siyanopropiltrimetoksisilan (CPTMS) ile modifiye edilmiş ITO substratı üzerinde immobilizasyonu ile oluşturulmuştur. Anti-CDH 22 antikorlarının CPTMS silanizasyon ajanına etkili bağlanması, morfolojik karakterizasyon (Taramalı Elektron Mikroskobu (SEM), Atomik Kuvvet Mikroskobu (AFM)) ve elektrokimyasal karakterizasyon (Elektrokimyasal İmpedans Spektroskopisi (EIS), Siklik Voltammetri (CV) kullanılarak incelendi. Optimum deney koşulları altında, ITO / CPTMS ile modifiye edilmiş elektrot, anti-CDH 22 antikor bağlanması için iyi bir bağlayıcıydır. Ek olarak, CPTMS modifiye elektrot CDH 22 antijen tespiti için etkili bir yüzey sunmuştur. İmmünosensör, geniş bir lineer tespit aralığı (0.03-3 pg/mL) ile düşük tespit limiti (9 fg/mL) ile sahipti. Ayrıca, iyi tekrarlanabilirlik, mükemmel tekrarlanabilirlik ve uzun depolama kararlılığına sahipti. Ek olarak, önerilen immünosensörün pratik uygulanabilirliği, insan serum numuneleri kullanılarak araştırıldı. İnsan serum numuneleri geri kazanım sonuçları (% 99.16 -% 101.94) önerilen biyosensörün doğruluğunu göstermektedir. Sonuç olarak, CPTMS, biyosensör yapımı için umut verici bir platform olabilir ve bu önerilen immünosensör gerçek insan serum analizi için uygulanabilir

Highly sensitive impedimetric immunosensor for determination of interleukin 6 as a cancer biomarker by using conjugated polymer containing epoxy side groups modified disposable ITO electrode

A novel impedimetric immunosensor based on a conjugated polypyrrole polymer containing epoxy active side groups (PPCE) modified indium tin oxide (ITO) electrode was developed for detection of interleukin 6 (IL 6), a prostate cancer biomarker. IL 6 receptor was used as a biorecognition molecule and successfully immobilized by covalent linkage on the modified ITO electrode. Pyrrole monomer containing epoxy active side group was electropolymerized on the disposable ITO electrode for the first time and used as an immobilization matrix for IL 6 receptor. The designed biosensor fabrication stages were analyzed by using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) techniques. For the quantification of IL 6 biomarker, EIS technique was utilized. In addition, the specific immuno-interaction between IL 6 receptor and IL 6 antigen was followed by single frequency impedance (SFI) technique. The resulting biosensor exhibited a linear calibration curve over the 0.02–16 pg/mL IL 6 concentration range, a limit of detection (LOD) of 6.0 fg/mL and a good selectivity against other interference biomarkers. Additionally, an excellent reproducibility, a long storage stability and an acceptable repeatability were found. The proposed impedimetric immunosensor was applied successfully to quantify for the IL 6 biomarker in human serum and it displayed a remarkable response in the real sample analysis with serum samples. In comparison with the commercial ELISA kit, the immunosensor provided a lower LOD and a lower analysis cost. In conclusion, the proposed impedimetric immunosensor could be clinically useful in the early diagnosis of the prostate cancer by detection of the serum samples after only simple dilution with phosphate buffer. © 2020 Elsevier B.V

A sensitive and label-free electrochemical impedance immunosensor for CDH 22 biomarker detection based on organo-functional silane modified ITO electrode

In this work, a novel electrochemical label free immunosensor was fabricated for Cadherin-like protein 22 (CDH 22) biomarker detection based on specific immunoreaction between anti-CDH 22 antibody and CDH 22 antigen. The developedimmunosensor was constructed through the immobilization of anti-CDH 22 antibodies on 3-cyanopropyltrimethoxysilane (CPTMS) modified ITO substrate. The effective binding of the anti-CDH 22 antibodies on the CPTMS silanization agentwas investigated by using morphological characterization (Scanning Electron Microscopy (SEM), Atomic Force Microscopy(AFM)) and electrochemical characterization (Electrochemical Impedance Spectroscopy (EIS), Cyclic Voltammetry (CV)).Under optimum experimental conditions, the ITO/CPTMS modified electrode was a good linker for anti-CDH 22 antibodyanchoring. In addition, CPTMS modified electrode offered an efficient surface to CDH 22 antigen detection. The immunosensor had a wide linear detection range (0.03-3 pg/mL) with low detection limit (9 fg/mL). Also, it had good reproducibility,excellent repeatability and long storage stability. In addition, the practical applicability of the proposed immunosensor wasinvestigated by utilizing human serum samples. The human serum samples recovery results (99.16% - 101.94%) illustratedthe accuracy of the suggested biosensor. Consequently, CPTMS can be a promising platform for biosensor construction andthis suggested immunosensor can be applicable for real human serum analysis.Bu çalışmada, anti-CDH 22 antikoru ve CDH 22 antijeni arasındaki spesifik immüno-reaksiyona dayanan, kadherin benzeri protein (CDH 22) biyobelirtecinin tespiti için yeni bir elektrokimyasal etiketsiz immünosensör üretilmiştir. Geliştirilen immünosensör, anti-CDH 22 antikorlarının 3-siyanopropiltrimetoksisilan (CPTMS) ile modifiye edilmiş ITO substratı üzerinde immobilizasyonu ile oluşturulmuştur. Anti-CDH 22 antikorlarının CPTMS silanizasyon ajanına etkili bağlanması, morfolojik karakterizasyon (Taramalı Elektron Mikroskobu (SEM), Atomik Kuvvet Mikroskobu (AFM)) ve elektrokimyasal karakterizasyon (Elektrokimyasal İmpedans Spektroskopisi (EIS), Siklik Voltammetri (CV) kullanılarak incelendi. Optimum deney koşulları altında, ITO / CPTMS ile modifiye edilmiş elektrot, anti-CDH 22 antikor bağlanması için iyi bir bağlayıcıydır. Ek olarak, CPTMS modifiye elektrot CDH 22 antijen tespiti için etkili bir yüzey sunmuştur. İmmünosensör, geniş bir lineer tespit aralığı (0.03-3 pg/mL) ile düşük tespit limiti (9 fg/mL) ile sahipti. Ayrıca, iyi tekrarlanabilirlik, mükemmel tekrarlanabilirlik ve uzun depolama kararlılığına sahipti. Ek olarak, önerilen immünosensörün pratik uygulanabilirliği, insan serum numuneleri kullanılarak araştırıldı. İnsan serum numuneleri geri kazanım sonuçları (% 99.16 -% 101.94) önerilen biyosensörün doğruluğunu göstermektedir. Sonuç olarak, CPTMS, biyosensör yapımı için umut verici bir platform olabilir ve bu önerilen immünosensör gerçek insan serum analizi için uygulanabilir

DETERMINATION OF SPECIFIC BIOMARKERS WITH DISPOSABLE BIOSENSOR SYSTEMS AND INVESTIGATION OF USEAGE IN CANCER EARLY DIAGNOSIS

Kanser çağın hastalığı olarak bilinir ve insan sağlığını önemli ölçüde tehdit eder. Biyomarkerların tanımlanması ve tayin edilmesi kanserin erken evresinde önemli bir role sahiptir. Biyomarkerler tükrük, serum, plazma ve dokuda bulunurlar. Bu nedenle, kanser biyomarkerlarının biyolojik sıvılarda ölçülerek kanserin erken saptanması mümkündür. Biyomarker ölçümü genellikle serum örneklerinde yapılır. Bununla birlikte, son araştırmalar, tükürükte kandaki çeşitli protein bileşenlerinin de bulunduğunu göstermiştir. Tükürük, kolay erişilebilir biyolojik sıvı olması nedeniyle dikkat çekmiştir. Tükürük örneklerinin toplanması, depolanması ve transferi kolaydır. Tükürük analizi, farklı kanser türlerinin teşhisi için istenen ve umut verici bir platform sağlar. Sonuç olarak, kanser biyobelirteçlerinin doğru ve hassas tespiti, kanserin tedavisini kolaylaştırır. Bu tez çalışmasında kanser biyomarkerlarının vücut sıvılarında tespitini sağlamak amacıyla 6 farklı biyosensör üretilmiştir. Her bir biyosensörde farklı elektrot dizaynları kullanılmıştır. İnterleukin 1?, interleukin 1? ve interleukin 8 analizlenmesi hedeflenen kanser biyomarkerlarıdır. 6-fosfonohegzanoik asit (PHA), 3-fosfonopropiyonik asit (PHP), 3-(trietoksisilil)propil isosiyanat) (IPTES), lineer polimer poly(glisilmetakrilat), Super P- poly(glisilmetakrilat) polimer kompozit ara yüzey materyalleri olarak kullanılmıştır. Anti-interleukin 1?, anti-interleukin 1? ve anti-interleukin 8 biyotanıma elementi olarak kullanılmıştır. Elektrot yüzeyinde yapılan modifikasyonlar elektrokimyasal ii teknikler (elektrokimyasal impedans spektroskopi, dönüşümlü voltammetri) ve morfolojik teknikler (taramalı elektron mikroskobu, atomik kuvvet mikroskobu) ile karakterize edilmiştir. Ayrıca antikorlar ile antijenler arasındaki etkileşimi izlemek için sabit frekans impedans ölçümleri de yapılmıştır. Biyosensörlerin tekrarlanabilirliği, tekrar üretilebilirliği, raf ömrü, tekrar kullanılabilme yeteneği de izlenmiştir. Ek olarak, biyosensörlerin klinik başarısını izlemek için serum ve tükürük örneklerinde biyomarker tayini gerçekleştirilmiştir. Gerek ELISA testi gerekse standart katma metodu biyosensörün başarısını kanıtlamaktadır.Cancer is known as a disease of epoch and it threats human health significantly. The identification and determination of biomarkers has a significant role in the early stage of cancer. Biomarkers are present in saliva, serum, plasma and tissue. Therefore, the early detection of cancer is possible by measuring cancer biomarkers in biological fluids. The biomarker measurement is usually performed in serum samples. However, recent research has displayed that a variety of protein ingredients in blood are also present in saliva. Saliva, has attracted attention due to being easily accessible biological fluid. The collection, storage and transfer of saliva samples is easy. The analysis of saliva provides a desirable and promising platform for the diagnosis of different types of cancers. Consequently, the accurate and sensitive detection of cancer biomarkers facilitates the treatment of cancer. In this thesis, six different biosensors have been produced to detect cancer biomarkers in body fluids. Each biosensor is fabricated with different electrode designs. Interleukin-1a, interleukin-1 and interleukin-8 are the cancer biomarkers targeted for analysis. 6-phosphonohexanoic acid (PHA), 3-phosphonopropionic acid (PHP), 3- (triethoxysilyl) propyl isocyanate (IPTES), linear polymer poly (glycylmethacrylate) and Super P-poly (glycylmethacrylate) polymer composite interface materials. Anti-interleukin 1?, anti-interleukin 1? and anti-interleukin 8 were used as biorecognition elements. The modifications performed on the electrode surface are characterized by electrochemical techniques (electrochemical impedance spectroscopy, alternating voltammetry) and morphological techniques (scanning electron microscopy, atomic force microscopy). Single frequency impedance measurements were also performed to monitor the interaction between the antibodies and the antigens. Repeatability, reproducibility, shelf life, reusability of biosensors has also been monitored. In addition, biomarker deteminations were performed in serum and saliva samples to monitor the clinical success of biosensors. Whether the ELISA test is required or the standard addition method proves the success of the biosensor

Novel electrochemical biosensing platform based on conductive multilayer for sensitive and selective detection of CYFRA 21-1

In the present work, an electrochemical biosensor modified with a conductive multilayer composed of gold nanoparticles and amino-substituted-pyrrole polymer (AuNPs/P(PyAmn)) was constructed for label-free detec-tion of cytokeratin 19 fragment 21-1 (CYFRA 21-1), one of the most important lung cancer biomarkers. The electrochemical biosensor was fabricated by electropolymerization of PyAmn on an indium tin oxide (ITO) platform with electrodeposition of AuNPs and binding of an anti-CYFRA 21-1 recognition element on the P (PyAmn)-coated electrode via glutaraldehyde crosslinking. In the present immunosensor, AuNPs deposition provided excellent conductivity and good electron transfer. The electropolymerization of the P(PyAmn) polymer layer ensured a large surface area that increased the amount of anti-CYFRA 21-1 antibodies that could be attached. A specific immunoreaction occurred between anti-CYFRA 21-1 antibody and CYFRA 21-1 antigen when the immunosensor was successively reacted with the target CYFRA 21-1 protein. According to specific immu-noreactions, the resulting biosensor produced an impedimetric signal proportional to the amount of CYFRA 21-1 in the linear detection range of 0.015-90 pg/mL. With optimal fabrication parameters, the detection limit, quantification limit and sensitivity for CYFRA 21-1 were 4.59 pg/mL, 15.31 pg/mL and 0.21 k Omega pg(-1) mL cm(-2), respectively. Meanwhile, this biosensor had good stability and high specificity for CYFRA 21-1 detection, and it was successfully applied to real serum samples. It also had a satisfactory rate of R-2 = 0.9984. The use of a disposable ITO substrate as a basis for this immunosensor allowed the use of simple instrumentation. This study illustrates a new approach to fabricate an ultrasensitive and label-free electrochemical biosensor based on a disposable platform for CYFRA 21-1 analysis in clinical biosensing.Scientific and Technological Research Council of Tekirdag ?; [NKU- BAP.00]This study was funded by the Scientific and Technological Research Council of Tekirdag ? Nam?k Kemal University, (Project number: NKU- BAP.00.GA.21.328)

Highly sensitive electrochemical immunosensor based on polythiophene polymer with densely populated carboxyl groups as immobilization matrix for detection of interleukin 1 beta in human serum and saliva

A new impedimetric immunosensor was fabricated for detection of Interleukin 1 beta (IL-1 beta) by using semi-conductive poly(2-thiophen-3-yl-malonic acid) (P3-TMA) as an immobilization matrix material and anti-IL-1 beta antibody as a biorecognition element for the first time. The polymer P3-TMA bound onto hydroxylated ITO surface via ester bond to form a polymer interface including active carboxyl groups. These reactive carboxyl groups bound to anti-IL-1 beta antibodies via amide bond under coupling reagent of N-beta-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride/N-hydroxysuccinimide. The detection of IL-1 beta antigen was monitored with electrochemical impedance spectroscopy technique (EIS). Apart from EIS technique, cyclic voltammetry (CV), fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), SEM-energy dispersive X-ray (EDX) mapping, atomic force microscopy (AFM) were used for characterization of immunosensor. The effect of antibody and antigen incubation durations, and utilized biorecognition element concentrations were investigated to determine the optimum analytical performance of the immunosensor. Under optimized conditions, the relative change in impedance was proportional to the IL-1 beta concentration in the range of 0.01-3 pg/mL with the detection limit 3 fg/mL. The proposed immunosensor had good specificity, reproducibility and stability. The immunosensor was applicable for detection of IL-1 beta in human serum and saliva samples with satisfied recoveries (97.4-104.5%). (C) 2018 Elsevier B.V. All rights reserved.TUBITAK (Scientific and Technological Research Council of Turkey)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [113 Z 678]The financial support from TUBITAK (The Scientific and Technological Research Council of Turkey, Project number: 113 Z 678) is gratefully acknowledged

A highly sensitive immunosensor based on ITO thin films covered by a new semi-conductive conjugated polymer for the determination of TNF alpha in human saliva and serum samples

A novel, ultrasensitive impedimetric immunosensor was constructed for the detection of tumor necrosis factor alpha (TNF alpha) by using Poly(3-thiophene acetic acid) (P3), a conjugated polymer as an immobilization matrix. The polymer P3 contains a lot of carboxylic acid groups on its surface that provide a larger biorecognition surface. This developed immunosensor was prepared on hydroxy-bearing ITO surface via an ester bond linkage of polymer P3 to immobilize anti-TNF alpha antibodies. The ITO electrode modification steps and interaction between anti-TNF alpha antibody and TNF alpha antigen were monitored by cyclic voltammetry (CV) and by electrochemical impedance spectroscopy (EIS) method. After the analytical parameters optimization, a linear detection response from 0.01 pg/mL to 2 pg/mL, a limit of detection LOD of 3.7 fg/mL and a limit of quantification (LOQ) of 12.4 fg/mL were achieved, which provided accurate results (relative standard deviation; 4.03%). The characterization of this developed immunosensor was performed by using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), SEM-energy dispersive X-ray (EDX) mapping and atomic force microscopy (AFM). The immunosensor allowed a simple and fast detection of TNF alpha antigen in human serum and satisfied recoveries (98.69-105.20%) were obtained by using standard addition method.TUBITAK (The Scientific and Technological Research Council of Turkey)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [113 Z 678]The financial support from TUBITAK (The Scientific and Technological Research Council of Turkey, Project number: 113 Z 678) is gratefully acknowledged

Biosensors in Drug Discovery and Drug Analysis

Background: The determination of drugs in pharmaceutical formulations and human biologic fluids is important for pharmaceutical and medical sciences. Successful analysis requires low sensitivity, high selectivity and minimum interference effects. Current analytical methods can detect drugs at very low levels but these methods require long sample preparation steps, extraction prior to analysis, highly trained technical staff and high-cost instruments. Biosensors offer several advantages such as short analysis time, high sensitivity, real-time analysis, low-cost instruments, and short pretreatment steps over traditional techniques. Biosensors allow quantification not only of the active component in pharmaceutical formulations, but also the degradation products and metabolites in biological fluids. The present review gives comprehensive information on the application of biosensors for drug discovery and analysis. Moreover, this review focuses on the fabrication of these biosensors. Methods: Biosensors can be classified as the utilized bioreceptor and the signal transduction mechanism. The classification based on signal transductions includes electrochemical optical, thermal or acoustic. Electrochemical and optic transducers are mostly utilized transducers used for drug analysis. There are many biological recognition elements, such as enzymes, antibodies, cells that have been used in fabricating of biosensors. Aptamers and antibodies are the most widely used recognition elements for the screening of the drugs. Electrochemical sensors and biosensors have several advantages such as low detection limits, a wide linear response range, good stability and reproducibility. Optical biosensors have several advantages such as direct, real-time and label-free detection of many biological and chemical substances, high specificity, sensitivity, small size and low cost. Modified electrodes enhance sensitivity of the electrodes to develop a new biosensor with desired features. Chemically modified electrodes have gained attention in drug analysis owing to low background current, wide potential window range, simple surface renewal, low detection limit and low cost. Modified electrodes produced by modifying of a solid surface electrode via different materials (carbonaceous materials, metal nanoparticles, polymer, biomolecules) immobilization. Recent advances in nanotechnology offer opportunities to design and construct biosensors. Unique features of nanomaterials provide many advantages in the fabrication of biosensors. Nanomaterials have controllable chemical structures, large surface to volume ratios, functional groups on their surface. To develop protein-inorganic hybrid nanomaterials, four preparation methods have been used. These methods are immobilization, conjugation, crosslinking and self-assembly. In the present manuscript, applications of different biosensors, fabricated by using several materials, for drug analysis are reviewed. The biosensing strategies are investigated and discussed in detail. Results: Several analytical techniques such as chromatography, spectroscopy, radiometry, immunoassays and electrochemistry have been used for drug analysis and quantification. Methods based on chromatography require time-consuming procedure, long sample-preparation steps, expensive instruments and trained staff. Compared to chromatographic methods, immunoassays have simple protocols and lower cost. Electrochemical measurements have many advantages over traditional chemical analyses and give information about drug quantity, metabolic fate of drugs, and pharmacological activity. Moreover, the electroanalytical methods are useful to determine drugs sensitively and selectivity. Additionally, these methods decrease analysis cost and require low-cost instruments and simple sample pretreatment steps. Conclusion: In recent years, drug analyses are performed using traditional techniques. These techniques have a good detection limit, but they have some limitations such as long analysis time, expensive device and experienced personnel requirement. Increased demand for practical and low-cost analytical techniques biosensor has gained interest for drug determinations in medical sciences. Biosensors are unique and successful devices when compared to traditional techniques. For drug determination, different electrode modification materials and different biorecognition elements are used for biosensor construction. Several biosensor construction strategies have been developed to enhance the biosensor performance. With the considerable progress in electrode surface modification, promotes the selectivity of the biosensor, decreases the production cost and provides miniaturization. In the next years, advances in technology will provide low cost, sensitive, selective biosensors for drug analysis in drug formulations and biological samples

Fabrication of electrochemical immunosensor based on acid-substituted poly(pyrrole) polymer modified disposable ITO electrode for sensitive detection of CCR4 cancer biomarker in human serum

This study described the first impedimetric immunosensor reported for the determination of CCR4, a new prostate cancer biomarker. This impedimetric immunosensor was constructed through the modification of disposable indium tin oxide (ITO) sheet with a conjugated pyrrole polymer P(Pyr-Pac) and subsequent immobilization of anti-CC chemokine receptor 4 (CCR4) antibodies. Acid-substituted poly(pyrrole) P(Pyr-Pac) polymer contained a lot of carboxyl groups on its end site, which were suitable for attachment of anti-CCR4 antibodies. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) were chosen to investigate electrode preparation stages and, EIS was chosen to detect the CCR4 concentration. Anti-CCR4 antibody attached biosensing surface was highly selective to CCR4 antigen, the specific interaction resulted changes in electrochemical signal. Optimization studies containing polymer amount, anti-CCR4 antibody concentration, anti-CCR4 antibody immobilization time and anti-CCR4 antibody-CCR4 antigen interaction time were studied. The developed immunosensor displayed a linear increase with concentrations of CCR4 antigen (0.02–8 pg/mL) and a low detection limit of 6.4 fg/mL. In addition, this biosensor had great reproducibility and repeatability. Moreover, the designed biosensor was successfully used for the quantification of CCR4 antigen in serum samples. The recovery for the spiked serum samples was between 98.25% and 103.99%. The suggested immunosensor illustrated a good selectivity towards some interferents including different biomarkers. This study could establish a new approach for future cancer biomarker detection. © 2020 Elsevier B.V.Çanakkale Onsekiz Mart Üniversitesi, ÇOMÜ; Consejo Nacional para Investigaciones Científicas y Tecnológicas, CONICIT; FUK-2018-1396This research was supported The Scientific and Technological Research Council of by ?anakkale Onsekiz Mart University, ?OM?-BAP (Grant number: FUK-2018-1396).This research was supported The Scientific and Technological Research Council of by Çanakkale Onsekiz Mart University , ÇOMÜ-BAP (Grant number: FUK-2018-1396 )

Impedimetric Detection of Calreticulin by a Disposable Immunosensor Modified with a Single-Walled Carbon Nanotube-Conducting Polymer Nanocomposite

A label-free impedimetric immunosensing system was constructed for ultrasensitive determination of the calreticulin (CALR) biological marker in human serum samples utilizing an electrochemical impedance spectroscopy analysis technique for the first time. The new biosensor fabrication procedure consisted of electro-deposition of single-walled carbon nanotubes (SWCNTs) incorporating polymerization of an oxiran-2-yl methyl 3-(1H-pyrrol-1-yl) propanoate monomer (Pepx) onto a low-cost and disposable indium tin oxide (ITO) electrode. The SWCNTs-PPepx nanocomposite layer was prepared onto the ITO after the one-step fabrication procedure. The fabrication procedure of the immunosensor and the characteristic biomolecular interactions between the anti-CALR and CALR were characterized by electrochemical analysis and morphological monitoring techniques. Under optimum conditions, the proposed biosensor was responsive to CALR concentrations over the detection ranges of 0.015-60 pg/mL linearly, and it had a very low detection limit (4.6 fg/mL) and a favorable sensitivity (0.43 k omega pg(-1) mL cm(-2)). The reliability of the biosensor system in clinical analysis was investigated by successful quantification of CALR levels in human serum. Moreover, the repeatability and reproducibility results of the biosensor were evaluated by using Dixon, Grubbs, T-test, and F-tests. Consequently, the proposed biosensor was a promising method for scientific, rapid, and successful analysis of CALR in human serum samples.Scientific and Technological Research Council of Canakkale Onsekiz Mart University [FHD-2021-3533]The authors gratefully acknowledge support from project FHD-2021-3533 of the Scientific and Technological Research Council of Canakkale Onsekiz Mart University. We thank Assoc. Prof. Pinar Ilgin for her support in the FTIR analysis