Sensitive sandwich-type voltammetric immunosensor for breast cancer biomarker HER2 detection based on gold nanoparticles decorated Cu-MOF and Cu2ZnSnS4 NPs/Pt/g-C3N4 composite

A sandwich-type sensitive voltammetric immunosensor for breast cancer biomarker human epidermal growth factor receptor 2 (HER2) detection was prepared. The electrochemical immunosensor was developed based on gold nanoparticles decorated copper-organic framework (AuNPs/Cu-MOF) and quaternary chalcogenide with platinum-doped graphitic carbon nitride (g-C3N4). Cu2ZnSnS4 nanoparticle (CZTS NP) quaternary chalcogenide with platinum (Pt)-doped g-C3N4 composite (Pt/g-C3N4) was tagged as CZTS NPs/Pt/g-C3N4. AuNPs/Cu-MOF composite was successfully synthesized by amidation reaction between AuNPs functionalized with amino group and Cu-MOFs containing carboxylic acid. After the conjugations of primer HER2 antibody and antigen HER2 protein to AuNPs/Cu-MOF as sensor platform, CZTS NPs/Pt/g-C3N4 composite was prepared by one-pot hydrothermal method. After immune reaction of 30 min, the prepared HER2 immunosensor was characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), x-ray diffraction (XRD) method, x-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The developed immunosensor showed high sensitivity with a detection limit of 3.00 fg mL−1. Additional properties of the voltammetric immunosensor are high selectivity, stability, reproducibility, and reusability. Graphical abstract: [Figure not available: see fulltext.]. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH, AT part of Springer Nature

Novel voltammetric tumor necrosis factor-alpha (TNF-α) immunosensor based on gold nanoparticles involved in thiol-functionalized multi-walled carbon nanotubes and bimetallic Ni/Cu-MOFs

TNF-α, as a pro-inflammatory cytokine, regulates some physiological and pathological courses. TNF-α level increases in some important diseases such as cancer, arthritis, and diabetes. In addition, it displays an important function in Alzheimer’s and cardiovascular diseases. Herein, a novel, sensitive, and selective voltammetric TNF-α immunosensor was prepared by using gold nanoparticles involved in thiol-functionalized multi-walled carbon nanotubes (AuNPs/S-MWCNTs) as sensor platform and bimetallic Ni/Cu-MOFs as sensor amplification. Firstly, the sensor platform was developed on glassy carbon electrode (GCE) surface by using mixture of thiol-functionalized MWCNTs (S-MWCNTs) and AuNPs. Then, capture TNF-α antibodies were conjugated to sensor platform by amino-gold affinity. After capture TNF-α antibodies’ immobilization, a new-type voltammetric TNF-α immunosensor was developed by immune reaction between AuNPs/S-MWCNTs immobilized with primer TNF-α antibodies and bimetallic Ni/Cu-MOFs conjugated with seconder TNF-α antibodies. The prepared TNF-α immunosensor was characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), x-ray diffraction (XRD) method, x-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), thermogravimetric analysis, Fourier transform infrared spectroscopy (FTIR), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). A linearity range of 0.01–1.0 pg mL−1 and a low detection limit of 2.00 fg mL−1 were also obtained for analytical applications. Graphical abstract: [Figure not available: see fulltext.] © 2021, Springer-Verlag GmbH Germany, part of Springer Nature

A novel QCM immunosensor development based on gold nanoparticles functionalized sulfur-doped graphene quantum dot and h-ZnS-CdS NC for Interleukin-6 detection

Interleukin 6 (IL-6) acts as both a proinflammatory and anti-inflammatory cytokine and is generally utilized as an important diagnostic biomarker for sepsis. In addition, the high levels of IL-6 measured in plasma have been associated with pathological inflammation. A novel quartz crystal microbalance (QCM) immunoassay method was presented for high sensitivity and selectivity detection of interleukin-6 (IL-6) based on gold nanoparticles functionalized sulfur-doped graphene quantum dot (AuNPs/S-GQD) and hollow ZnS–CdS nanocage (h-ZnS-CdS NC). Firstly, AuNPs/S-GQD nanocomposite was synthesized in the presence of tetrachloroauric acid and then conjugated onto anti-IL-6 antibodies by amino-gold affinity. The sandwich-type QCM immunoassay probe was prepared by immune-reaction between AuNPs/S-GQD/QCM immobilized with anti-IL-6 capture antibodies and h-ZnS-CdS NC including detection anti-IL-6 antibodies in the presence of target IL-6. The prepared QCM immunoassay probe was characterized by transmission electron microscopy (TEM), scanning electron microscope (SEM), x-ray diffraction (XRD) method, x-ray photoelectron spectroscopy (XPS), Raman spectroscopy, UV–vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The QCM immunosensor showed a linearity range (0.01–2.0 pg mL−1) and a low detection limit (3.33 fg mL−1). Lastly, high stable and selective QCM immunosensor was applied to prepared plasma samples with good recovery. © 2021 Elsevier B.V

Electrochemical cardiac troponin I immunosensor based on nitrogen and boron-doped graphene quantum dots electrode platform and Ce-doped SnO2/SnS2 signal amplification

The detection of acute myocardial infarction directly depends on the concentration of the cardiac troponin I (CTnI) in human blood plasma. In this study, the sensitive, selective, and fast sandwich-type electrochemical CTnI immunosensor was developed by using nitrogen and boron-dopped graphene quantum dots -as electrode platform and two-dimensional Ce-dopped SnO2/SnS2 (Ce–SnO2/SnS2) as signal amplification. In preparation of electrochemical CTnI immunosensor, the coordinated covalent bond between capture antibody (anti-CTnI-Ab1) and nitrogen and boron-dopped graphene quantum dots as electrode platform led to immobilization of anti-CTnI-Ab1, and the strong esterification between the secondary antibody (anti-CTnI-Ab2) and thioglycolic acid-modified Ce–SnO2/SnS2 resulted in anti-CTnI-Ab2 conjugation. Finally, the resultant electrochemical CTnI immunosensor was formed via antigen-antibody interaction. High-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, UV–Vis spectroscopy and Raman spectroscopy, as well as some electrochemical characterization techniques, including cyclic voltammetry, differential pulse voltammetry and electrochemical impedance spectroscopy were used to characterize the prepared immunosensor. The detection limit of CTnI in plasma samples was calculated as 2.00 fg mL−1, making it an effective tool for acute myocardial infarction testing. © 2021 Elsevier Lt

L-Phenylalanine-Imprinted Electrochemical Sensor Based on WS2 Nanoflowers on N,B-Doped Graphene and Its Application to Milk Samples

Phenylketonuria (PKU) is a critical disease in the disorder of amino acid metabolism, which mostly emerges in children. The most common method used in PKU treatment is the detection of L-phenylalanine (PHEA) as the biomarker of PKU. In the present work, a new molecularly imprinted electrochemical electrode based on WS2 nanoflowers (NFs) on N,B-doped graphene (WS2 NFs/N,B-GR) is presented for PHEA assay in milk samples. First of all, WS2 NFs/N,B-GR was synthesized via a high-efficiency hydrothermal synthesis. Cyclic voltammetry was applied to the electrochemical cell, including PHEA as a template molecule and pyrrole as a monomer, to form PHEA-imprinted electrochemical electrodes. Then, the structural and morphological features of WS2 NFs and WS2 NFs/N,B-GR were investigated in detail by various analytical methods. The limit of quantification and limit of detection values were obtained as 1.0 × 10-11 and 3.0 × 10-12 M, respectively, by a PHEA-imprinted electrochemical electrode. Finally, a PHEA-imprinted electrochemical sensor having a high degree of selectivity, stability, and reusability is presented in the literature for early diagnosis of PKU. © 2022 American Chemical Society. All rights reserved

Identification of heavy metal ions from aqueous environment through gold, Silver and Copper Nanoparticles: An excellent colorimetric approach

Heavy metal pollution has become a severe threat to human health and the environment for many years. Their extensive release can severely damage the environment and promote the generation of many harmful diseases of public health concerns. These toxic heavy metals can cause many health problems such as brain damage, kidney failure, immune system disorder, muscle weakness, paralysis of the limbs, cardio complaint, nervous system. For many years, researchers focus on developing specific reliable analytical methods for the determination of heavy metal ions and preventing their acute toxicity to a significant extent. The modern researchers intended to utilize efficient and discerning materials, e.g. nanomaterials, especially the metal nanoparticles to detect heavy metal ions from different real sources rapidly. The metal nanoparticles have been broadly utilized as a sensing material for the colorimetric detection of toxic metal ions. The metal nanoparticles such as Gold (Au), Silver (Ag), and Copper (Cu) exhibited localized plasmon surface resonance (LPSR) properties which adds an outstanding contribution to the colorimetric sensing field. Though, the stability of metal nanoparticles was major issue to be exploited colorimetric sensing of heavy emtal ions, but from last decade different capping and stabilizing agents such as amino acids, vitmains, acids and ploymers were used to functionalize the metal surface of metal nanoparticles. These capping agents prevent the agglomeration of nanoparticles and make them more active for prolong period of time. This review covers a comprehensive work carried out for colorimetric detection of heavy metals based on metal nanoparticles from the year 2014 to onwards. © 202

Evaluation of electrochemical behaviour of ezetimibe and analysis in pharmaceutical preparations by electroanalytical methods

Ezetimib (EZE), kolesterol absorpsiyon inhibitörü antihiperlipidemik ajanların ilk üyesidir. Bu tez çalışmasında, EZE'nin farmasötik preparatlardan miktar tayini amacıyla kare dalga voltametrisi (SWV), kare dalga adsorptif sıyırma voltametrisi (SWAdSV) ve diferansiyel puls adsorptif sıyırma voltametrisi (DPAdSV) gibi basit ve güvenilir elektroanalitik yöntemler uygulanmıştır. Öncelikle EZE tayini için şartlar optimize edilmiştir. Bunun sonucunda SWV yöntemi için 50 Hz'lik frekans, 3 mV'luk adım yüksekliği, 20 mV'luk puls genliğinde; SWAdSV yöntemi için - 800 mV'luk biriktirme potansiyeli, 4 mV'luk adım yüksekliği, 15 Hz'lik frekans, 25 mV'luk puls genliği, 15 s biriktirme süresinde; DPAdSV yöntemi için - 850 mV'luk birikirme potansiyeli, 20 mV / s'lik tarama hızı, 50 mV'luk puls genliği ve 15 s'lik biriktirme süresinde en iyi pikler elde edilmiştir. Gözlenebilme sınırı (LOD) ve alt tayin sınırı (LOQ) sırasıyla SWV yöntemi için 0.099 µg mL-1 ve 0.298 µg mL-1; SWAdSV yöntemi için 11.53 ng/mL ve 31.73 ng/mL; DPAdSV yöntemi için 20.26 ng/mL ve 62.46 ng/mL olarak elde edilmiştir. Doğrusallık aralıkları SWV yöntemi için 0.33 - 6.54 µg/mL; SWAdSV yöntemi için 33 - 596 ng/mL; DPAdSV yöntemi için 66 - 400 ng/mL olarak bulunmuştur. EZE derişimine bağlı olarak SWV yönteminde [(-1290) ? (-1322)] mV arasında SWAdSV yönteminde [(-1236) ? (-1252)] mV arasında ve DPAdSV yönteminde [(-1190) ? (-1210)] mV arasında indirgenme piki gözlenmiştir. Geliştirilen yöntemler ?International Conference on Harmonisation of Technical Requirements for Registration of Pharmacueticals for Human Use? (ICH)'a göre valide edilmiş ve doğrusal, duyarlı, özgün, doğru, kesin, sağlam ve tutarlı bulunmuştur. Bu yöntemler EZE içeren farmasötik preparatların analizine başarıyla uygulanmıştır. Elde edilen sonuçlar kaynaklarda verilen UV-spektrofotometrik yöntemle karşılaştırılmış ve istatistiksel olarak anlamlı bir fark bulunmamıştır. Ayrıca EZE'nin elektrokimyasal davranışları incelenmiştir. Bunun için yapılan dönüşümlü voltametri (CV) ve SWV deneylerinin sonucunda indirgenme mekanizmasının 2 elektronlu ve 2 protonlu olduğu, CV, kronoamperometri (CA) ve kronokulometri (CC) yöntemleri uygulanarak EZE'in indirgenme akımının difüzyon kontrollü ve elektrot tepkimesinin tersinmez olduğu bulunmuştur. İndirgenme tepkimesinin EC mekanizmasına göre yürüdüğü tespit edilmiş ve olası indirgenme mekanizması önerilmiştir. Elektrokimyasal tekniklerle EZE'in indirgenme tepkimesine ait difüzyon katsayısı (D), elektron aktarım hız sabiti (kf) ve kimyasal tepkimenin hız sabiti (k) hesaplanmıştır.Ezetimibe (EZE) is the first of a new class of antihyperlipidemic agents, the cholesterol ? absorption inhibitors. In this thesis study, a simple and reliable electroanalytical methods such as square wave voltammetry (SWV), square wave adsorptive stripping voltammetry (SWAdSV) and diferansiyel puls adsorptive stripping voltammetry (DPAdSV) are applied to estimate the amount of EZE in tablets. Firstly, the developed methods were optimized for the determination of EZE. The well-defined peaks were observed at the frequency of 50 Hz, amplitude of 20 mV, potential increment of 3 mV for SWV; at accumulation time of 15 s, accumulation potential of ? 800 mV, frequency of 15 Hz, amplitude of 25 mV, potential increment of 4 mV for SWAdSV; at accumulation time of 15 s, accumulation potential of ? 850 mV, scan rate of 20 mV / s and amplitude of 50 mV for DPAdSV. Limit of detection (LOD) and limit of quantification (LOQ) were found 0.099 µg/mL and 0.298 µg/mL for SWV, 11.53 ng/mL and 31.73 ng/mL for SWAdSV and 20.26 ng/mL and 62.46 ng/mL for DPAdSV respectively. The linearity ranges of EZE for SWV, SWAdSV and DPAdSV were found 0.33 - 6.54 µg/mL, 33 - 596 ng/mL and 66 - 400 ng/mL respectively. EZE gave rise to a single voltammetric peak in the potential interval from - 1290 to -1322 mV for SWV, from - 1236 to - 1252 mV for SWAdSV and from - 1190 to - 1210 mV for DPAdSV depending on EZE concentration. The developed methods were validated according to the ?International Conference on Harmonisation of Technical Requirements for Registration of Pharmacueticals for Human Use? (ICH) guideline and found to be linear, sensitive, specific, accurate, precise, accurate, robust and rugged. The methods were applied successfully for the determination of EZE in tablet dosage form. The data were compaired with ones obtained from the UV-spectrophotometric method given in the literature and no significant difference was found statistically. Also electrochemical behaviours of EZE were investigated. As a results of cyclic voltammetry (CV) and SWV experiments, the reduction mechanism included 2 electrons and 2 protons, and further more, reduction current of EZE was difusion controlled and the electrode reaction was found to be irreversible by using CV, chronoamperometry (CA) and choronocoulometry (CC) methods. It was found out that the reduction reaction occured according to EC mechanism and possible reduction mechanism was proposed. Using electrochemical techniques diffusion coefficient (D), rate constant for electron transfer (kf) and rate constant of chemical reaction (k) relating to EZE?s reduction reaction was calculated

Farmasötik Preparatlardan ve Gıdalardan Tobramisin Tayini İçin Moleküler Baskılanmış Nanosensörlerin Geliştirilmesi

In this thesis study, the molecularly imprinted glassy carbon and quartz crystal microbalance (QCM) nanosensors were developed for the determination of tobramycin. For QCM nanosensor, firstly the modification of gold surface of QCM chip was performed by self-assembling monolayer formation of allyl mercaptane to introduce polymerizable double bonds on the chip surface. Then, TOB imprinted poly(2-hydroxyethyl methacrylate?methacryloylamidoglutamic acid) film was generated on the gold surface. For electrochemical nanosensor, the electrode was prepared by incorporation of tobramycin molecule during the electropolymerization of pyrrole on glassy carbon electrode using cyclic voltammetry method. The performance of the imprinted and non-imprinted sensors was evaluated by QCM and square wave voltammetry (SWV) tecniques. The imprinted and non-imprinted sensors were characterized by using atomic force microscopy (AFM), Fourier transform infrared (FTIR) spectroscopy, ellipsometry, contact angle measurements, electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). Limit of detection (LOD) and limit of quantification (LOQ) were found as 0.00561 nM and 0.0166 nM for QCM and 0.166 nM and 0.491 nM for SWV, respectively. The linearity ranges of tobramycin for QCM and SWV were found as 0.017-0.150 nM and 0.5-10.0 nM respectively. The developed methods were validated according to the ?International Conference on Harmonisation of Technical Requirements for Registration of Pharmacueticals for Human Use? (ICH) guideline and found to be linear, sensitive, specific, accurate, precise, robust and rugged. The methods were applied successfully for the determination of tobramycin in pharmaceuticals and foods. In addition, association kinetic analysis and isotherm models were applied to data to explain adsorption process occured.Bu tez çalışmasında tobramisin tayini için moleküler baskılanmış camsı karbon ve kuvarz kristal mikrobalans (QCM) nanosensörleri geliştirilmiştir. QCM nanosensörü için, öncelikle QCM çipinin altın yüzeyinin modifikasyonu çip yüzeyine polimerize çift bağlarının girmesi için alil merkaptanın kendiliğinden oluşan tek tabaka yöntemiyle gerçekleştirilmiştir. Daha sonra çip yüzeyinde tobramisin baskılanmış poli(2-hidroksietil metakrilat-metakriloilamidoglutamik asit) filmi oluşturulmuştur. Elektrokimyasal nanosensör için, elektrot dönüşümlü voltametri yöntemi kullanılarak camsı karbon elektrot yüzeyinde pirolün elektropolimerizasyonu sırasında tobramisin molekülün katılmasıyla hazırlanmıştır. Baskılanmış ve baskılanmamış sensörlerin performansları QCM ve kare dalga voltametrisi (SWV) teknikleri ile değerlendirilmiştir. Baskılanmış ve baskılanmamış sensörler atomik kuvvet mikroskopu (AFM), Fourier dönüşümlü infrared (FTIR) spektroskopisi, elipsometre, temas açısı ölçümleri, elektrokimyasal impedans spektroskopisi (EIS) ve dönüşümlü voltametri teknikleri kullanarak karakterize edilmiştir. Gözlenebilme sınırı (LOD) ve alt tayin sınırı (LOQ) QCM yöntemi için sırasıyla 0.00561 nM ve 0.0166 nM ve SWV yöntemi için sırasıyla 0.166 nM ve 0.491 nM olarak bulunmuştur. Tobramisin için doğrusallık aralıkları QCM yöntemi için 0.017-0.150 nM ve SWV yöntemi için 0.5-10.0 nM olarak bulunmuştur. Geliştirilen yöntemler ?International Conference on Harmonisation of Technical Requirements for Registration of Pharmacueticals for Human Use? (ICH)?a göre valide edilmiş ve doğrusal, duyarlı, özgün, doğru, kesin, sağlam ve tutarlı bulunmuştur. Bu yöntemler farmasötik preparatlar ve gıdalardan tobramisin analizine başarıyla uygulanmıştır. Ayrıca bağlanma kinetik analizi ve izoterm modelleri sensör yüzeyinde gerçekleşen adsorpsiyon işlemini açıklamak için datalara uygulanmıştır

Development of molecular imprinted nanosensors for determination of tobramycin in pharmaceuticals and foods

Bu tez çalıĢmasında tobramisin tayini için moleküler baskılanmıĢ camsı karbon ve kuvarz kristal mikrobalans (QCM) nanosensörleri geliĢtirilmiĢtir. QCM nanosensörü için, öncelikle QCM çipinin altın yüzeyinin modifikasyonu çip yüzeyine polimerize çift bağlarının girmesi için alil merkaptanın kendiliğinden oluĢan tek tabaka yöntemiyle gerçekleĢtirilmiĢtir. Daha sonra çip yüzeyinde tobramisin baskılanmıĢ poli(2-hidroksietil metakrilat-metakriloilamidoglutamik asit) filmi oluĢturulmuĢtur. Elektrokimyasal nanosensör için, elektrot dönüĢümlü voltametri yöntemi kullanılarak camsı karbon elektrot yüzeyinde pirolün elektropolimerizasyonu sırasında tobramisin molekülün katılmasıyla hazırlanmıĢtır. BaskılanmıĢ ve baskılanmamıĢ sensörlerin performansları QCM ve kare dalga voltametrisi (SWV) teknikleri ile değerlendirilmiĢtir. BaskılanmıĢ ve baskılanmamıĢ sensörler atomik kuvvet mikroskopu (AFM), Fourier dönüĢümlü infrared (FTIR) spektroskopisi, elipsometre, temas açısı ölçümleri, elektrokimyasal impedans spektroskopisi (EIS) ve dönüĢümlü voltametri teknikleri kullanarak karakterize edilmiĢtir. Gözlenebilme sınırı (LOD) ve alt tayin sınırı (LOQ) QCM yöntemi için sırasıyla 0.00561 nM ve 0.0166 nM ve SWV yöntemi için sırasıyla 0.166 nM ve 0.491 nM olarak bulunmuĢtur. Tobramisin için doğrusallık aralıkları QCM yöntemi için 0.017-0.150 nM ve SWV yöntemi için 0.5-10.0 nM olarak bulunmuĢtur. GeliĢtirilen yöntemler ―International Conference on Harmonisation of Technical Requirements for Registration of Pharmacueticals for Human Use‖ (ICH)‘a göre valide edilmiĢ ve doğrusal, duyarlı, özgün, doğru, kesin, sağlam ve tutarlı bulunmuĢtur. Bu yöntemler farmasötik preparatlar ve gıdalardan tobramisin analizine baĢarıyla uygulanmıĢtır. Ayrıca bağlanma kinetik analizi ve izoterm modelleri sensör yüzeyinde gerçekleĢen adsorpsiyon iĢlemini açıklamak için datalara uygulanmıĢtır.In this thesis study, the molecularly imprinted glassy carbon and quartz crystal microbalance (QCM) nanosensors were developed for the determination of tobramycin. For QCM nanosensor, firstly the modification of gold surface of QCM chip was performed by self-assembling monolayer formation of allyl mercaptane to introduce polymerizable double bonds on the chip surface. Then, TOB imprinted poly(2-hydroxyethyl methacrylate–methacryloylamidoglutamic acid) film was generated on the gold surface. For electrochemical nanosensor, the electrode was prepared by incorporation of tobramycin molecule during the electropolymerization of pyrrole on glassy carbon electrode using cyclic voltammetry method. The performance of the imprinted and non-imprinted sensors was evaluated by QCM and square wave voltammetry (SWV) tecniques. The imprinted and non-imprinted sensors were characterized by using atomic force microscopy (AFM), Fourier transform infrared (FTIR) spectroscopy, ellipsometry, contact angle measurements, electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). Limit of detection (LOD) and limit of quantification (LOQ) were found as 0.00561 nM and 0.0166 nM for QCM and 0.166 nM and 0.491 nM for SWV, respectively. The linearity ranges of tobramycin for QCM and SWV were found as 0.017-0.150 nM and 0.5-10.0 nM respectively. The developed methods were validated according to the ―International Conference on Harmonisation of Technical Requirements for Registration of Pharmacueticals for Human Use‖ (ICH) guideline and found to be linear, sensitive, specific, accurate, precise, robust and rugged. The methods were applied successfully for the determination of tobramycin in pharmaceuticals and foods. In addition, association kinetic analysis and isotherm models were applied to data to explain adsorption process occured