Metamfetamine spesifik DNA aptamerinin geliştirilmesi

Metamfetamin yaygın olarak kötüye kullanımı olan yüksek derecede bağımlılık yapan uyarıcı ve nörotoksik bir ilaçtır. Metamfetamin kötüye kullanımı birçok tıbbi, sosyal ve ekonomik sorun ile ilişkilendirilmektedir. Metamfetamin kötüye kullanımı, tüm dünyada giderek artan uluslararası bir sorun haline gelmiştir. Bağımlılık toplumun karşı karşıya olduğu en yaygın, pahalı ve zorlayıcı sağlık sorunlarından biridir. Bununla birlikte, amfetamin türevlerinin (metamfetamin vb.) üretimi ve kötüye kullanımı artarak devam etmektedir. Birleşmiş Milletler Uyuşturucu ve Suç Ofisi verilerine göre dünya genelinde metamfetamin kullanıcılarının sayısı, hem opiat hem de kokain kullanıcılarının sayısı ile yarışır durumdadır. Önceki çalışmalarda, idrar, kan ve saç gibi biyolojik örnekle laboratuvar testleri, uyuşturucu kullanımını doğrulamak amaçlı kullanılmıştır. Bununla birlikte, örnek toplama sırasında değiştirme ya da yerine koyma gibi birçok problem ortaya çıkmaktadır. Düşük hassasiyet ve seçicilik, operasyonel uygulama zorlukları ve toksik çözücülerin kullanımı gibi çeşitli sınırlamalar, metamfetamin analizleri için yeni ve pratik yöntemlerin geliştirilmesine duyulan ihtiyacı doğurmuştur. Bu sınırlamaların bir sonucu olarak, bu yöntemlere alternatif olabilecek metamfetaminin belirlenmesi için daha hızlı ve daha ucuz yöntemler geliştirmeye ihtiyaç duyulmaktadır. Bu çalışmada, ssDNA aptamerleri GO-SELEX (Grafen Oksit-Ligandların Üstel Zenginleştirilmesi ve Sistematik Evrimi) yöntemi kullanılarak metamfetamin kullanımına karşı seçilmiştir. Aptamerler, dizilerine özgü üç boyutlu katlanmalarıyla hedeflerine oldukça yüksek afinite ve özgüllükle bağlanabilen tek iplikli DNA veya RNA oligonükleotidleridir. Aptamerler, üç boyutlu yapılarına bağlı olarak, tek bir molekülden karmaşık analit karışımına ve hücrelerden tüm organizmaya kadar birçok farklı ligand tipine bağlanacak şekilde geliştirilebilir. Küçük moleküller için aptamerlerin geliştirilmesi için en pratik ve seçici SELEX yöntemlerinden biri grafen oksit SELEX (GO-SELEX) 'dir. Bu çalışma kapsamında metamfetamin için geliştirilen aptamerler, izotermal titrasyon kalorimetrisi (ITC) ile karakterize edilmiştir. ITC analizi ile aptamerlerin hedef moleküle afiniteleri belirlenmiştir. Geliştirilmiş aptamerlerin seçiciliği ve afinitesi, biyolojik numunelerde µM seviyesinde afinite ile metamfetamin molekülünün analizi için yeni aptasensörlerin geliştirilmesi için ümit vericidir.Methamphetamine is a widely abused and highly addictive psychostimulant and neurotoxic drug. There are many medical, social and economic problems associated with methamphetamine abuse. Abuse of methamphetamine has become a growing international problem all over the world. Addiction is one of the most common, expensive and challenging health problems facing society. However, production and abuse of amphetamine derivatives (methamphetamine etc.) continues to increase. According to the United Nations Office on Drugs and Crime the number of methamphetamine users worldwide is close to the number of both opiate and cocaine users. In previous studies, laboratory tests of biological samples such as urine, blood and hair have been used to test drug abuse. However, many problems of sample obtaining difficulties and risk of adulteration or alteration appear. Various limitations such as low sensitivity and selectivity, operational implementation challenges and the use of toxic solvents have led to the need for the development of new and practical methods for methamphetamine analyses. As result of such limitations, there is a need to develop faster and cheaper methods to determine methamphetamine which may be an alternative to these methods. In this study, ssDNA aptamers were selected against methamphetamine by using GO-SELEX (Graphene-Oxide Systematic Evolution of Ligands by Exponential Enrichment) method. Aptamers are single-stranded DNA or RNA oligonucleotides that can bind with high affinity and specificity to their targets with their three-dimensional folding specific to their sequence. Aptamers can be developed to bind to many different ligand types, from a single molecule to complex analyte mixture and from cells to a whole organism, depending on their three-dimensional structure. One of the most practical and selective SELEX methods for the development of aptamers for small molecules is graphene-oxide SELEX (GO-SELEX). Within the framework of this study, aptamers developed for methamphetamine were characterized by isothermal titration calorimetry (ITC). The selectivity and affinity of the developed aptamers is promising for the development of novel aptasensors for the analysis of the methamphetamine molecule with µM level affinity in biological samples

Synthetic antibodies for methamphetamine analysis: Design of high affinity aptamers and their use in electrochemical biosensors

An aptamer-based electrochemical biosensor was designed and fabricated for methamphetamine (METH) anal-ysis. Several aptamer sequences developed by the GO-SELEX method were immobilized onto gold electrodes (GE) via gold-thiol affinity. Surface characterizations were performed by electrochemical methods including cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectrometry (EIS). GE/Apta-4/METH aptasensor was selected for further studies since the best results were obtained with the Apta-4 sequence in terms of analytical parameters. Accordingly, it exhibited good selectivity for METH analysis with a wide linear range of 0.1-50 ng/mL and a low limit of detection (LOD) which was found to be 0.467 ng/mL. The proposed aptasensor platform displayed good selectivity for the detection of METH in synthetic urine samples spiked with METH.This work was supported by the Republic of Turkey, Ministry of Development (Project Grant No: 2016 K121190) and partially by Ege University Scienti fi c Research Projects Coordination Unit (Project Grant No: 18 -FEN -006) . We thank Ege University Central Research Testing and Analysis Laboratory Research and Application Center (EGE-MATAL) for ITC measurements.Republic of Turkey, Ministry of Development [2016 K121190]; Ege University Scienti fi c Research Projects Coordination Unit [18 -FEN -006

A review of aptamer-conjugated nanomaterials for analytical sample preparation: Classification according to the utilized nanomaterials

Uğurlu Ö, Man E, Gök O, et al. A review of aptamer-conjugated nanomaterials for analytical sample preparation: Classification according to the utilized nanomaterials. Analytica Chimica Acta. 2024;1287: 342001.Background: Sample extraction before detection is a critical step in analysis. Since targets of interest are often found in complex matrices, the sample can not be directly introduced to the analytical instrument. Nanomaterials with unique physical-chemical properties are excellent supports for use in sorbent-based extraction. However, they lack selectivity and thus need to be functionalized with target-capturing molecules. Antibodies and molecularly imprinted polymers (MIPs) can be used for this purpose, but they have some problems that limit their practical applications. Hence, functionalization of nanomaterials for selectivity remains a problem. Results: Nucleic acid aptamers are affinity reagents that can provide superiority to antibodies since they can be selected in vitro and at a lower cost. Moreover, aptamers can be chemically synthesized and easily modified with different functional groups. Hence, aptamers are good candidates to impart selectivity to the nanomaterials. Recent studies focus on the integration of aptamers with magnetic nanoparticles, carbon-based nanomaterials, metal-organic frameworks, gold nanoparticles, gold nanorods, silica nanomaterials, and nanofibers. The unique properties of nanomaterials and aptamers make the aptamer-conjugated nanomaterials attractive for use in sample preparation. Aptamer-functionalized nanomaterials have been successfully used for selective extraction of proteins, small molecules, and cells from different types of complex samples such as serum, urine, and milk. In particular, magnetic nanoparticles have a wider use due to the rapid extraction of the sample under magnetic field. Significance: In this review, we aim to emphasize how beneficial features of nanomaterials and aptamers could be combined for extraction or enrichment of the analytes from complex samples. We aim to highlight that the benefits are twofold in terms of selectivity and efficiency when employing nanomaterials and aptamers together as a single platform

in vitro Selection of Aptamer for Imidacloprid Recognition as Model Analyte and Construction of a Water Analysis Platform

Evran, Serap/0000-0001-6676-4888; Ceylan, Ayse Elcin/0000-0002-0591-6080;WOS: 000535246200001Pesticide use in agriculture is one of the threats to water safety. Therefore, detection of pesticide residues is crucial for human health. Compared to conventional chromatographic methods, aptasensors are promising tools for fast, cheap and sensitive detection of environmental contaminants. To the best of our knowledge, such an aptasensor has not been reported for imidacloprid (Imi) which is one of the most widely used pesticides. in order to meet this demand, we initially selected two novel aptamers designated as 'Apta-1' and 'Apta-2' by graphene oxide-SELEX (GO-SELEX) method. Then, these aptamers were used to fabricate the gold electrode-based aptasensor platforms and characterized by using electrochemical methods such as cyclic voltammetry, and electrochemical impedance spectroscopy as well as X-Ray photoelectron spectroscopy. It was found that the limit of detection value of Apta-1 based sensor for the Imi was found better than Apta-2 based system, although linear ranges were similar. Based on that finding, Apta-1 based system was further tested against possible interference molecules. the proposed platform was successfully used for detection of very low concentrations of Imi in the range of ng/mL. Thus, it eliminates the need for sample pre-treatment and enables a practical analysis in real wastewater samples.EUEuropean Union (EU); FCT under the ERA-NET Cofund WaterWorks 2015 Call [Water-Works2015-AGRINUPES]; Scientific and Technological Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [117Y195]; Republic of Turkey, Ministry of DevelopmentTurkiye Cumhuriyeti Kalkinma Bakanligi [2016K121190]The authors would like to thank the EU and FCT for funding, in the frame of the collaborative international consortium AGRINUPES financed under the ERA-NET Cofund WaterWorks 2015 Call (Project code: Water-Works2015-AGRINUPES, Project name: Integrated monitoring and control of water, nutrients and plant protection products towards a sustainable agricultural sector). This ERA-NET is an integral part of the 2016 Joint Activities developed by the Water Challenges for a Changing World Joint Programme Initiative (Water JPI). This research was supported by the Scientific and Technological Research Council of Turkey (TUBITAK, Project Grant No: 117Y195). This work was also partially supported by Republic of Turkey, Ministry of Development (Project Grant No: 2016K121190). Ege University Central Research Testing and Analysis Laboratory Research and Application Center (EGE-MATAL) chromatography laboratories were used in this study. Also, we thank to Turkish Water Institute (SUEN) due to their contributions as one of the partner Institute in Turkey

Sensor Platform with a Custom-Tailored Aptamer for Diagnosis of Synthetic Cannabinoids

Ceylan, Ayse Elcin/0000-0002-0591-6080; Evran, Serap/0000-0001-6676-4888; BALABAN, Simge/0000-0002-4540-1882WOS: 000505868000001Synthetic cannabinoids (SCs) are the large group of abused drugs and detection of them is still a challenge. Hence, new methods for analysis of SCs are being investigated. We aimed to develop a novel system for selective analysis of SCs. First, various custom-tailored aptamers against the target SCs were selected through GO-SELEX process. Toggling between different SC analytes during successive rounds of selection was performed to generate cross-reactive aptamers. Then, the amino-capped aptamers were synthesized and easily attached to the cysteamine-covered gold electrodes. Analytical parameters and selectivity of the aptasensors were compared by using electrochemical techniques. After comparison of the analytical features and selectivity towards target analytes, one of the aptamers designated as Apta-1 was chosen for further measurements. the aptasensor was tested by using differential pulse voltammetry technique against JWH-018 (5-pentanoic acid), selected as a model for SCs. the linearity and limit of detection were determined as 0.01-1.0 ng/mL and 0.036 ng/mL. Finally, sample application in synthetic urine samples was successfully performed with standard addition method, as confirmed by LC-QTOF/MS. JWH-018 (4-hydroxypentyl), JWH-073 (3-hydroxybutyl), JWH-250 (5-hidroxypentyl) and HU-210 were used to test the selectivity of the aptasensor and the system was shown to recognize all these SCs. Also other illegal drugs did not significantly interfere with the signal responses.Scientific and Technological Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [117Z152]; Republic of Turkey, Ministry of DevelopmentTurkiye Cumhuriyeti Kalkinma Bakanligi [2016K121190]; Ege University Central Research Testing and Analysis Laboratory Research and Application Center (EGE-MATAL)This study was supported by the Scientific and Technological Research Council of Turkey (TUBITAK, Project Grant No: 117Z152). This work was also supported by Republic of Turkey, Ministry of Development (Project Grant No: 2016K121190) and Ege University Central Research Testing and Analysis Laboratory Research and Application Center (EGE-MATAL) chromatography laboratories were used in this study

Magnetic Nanoparticle-Based Electrochemical Sensing Platform Using Ferrocene-Labelled Peptide Nucleic Acid for the Early Diagnosis of Colorectal Cancer

Diagnostic biomarkers based on epigenetic changes such as DNA methylation are promising tools for early cancer diagnosis. However, there are significant difficulties in directly and specifically detecting methylated DNA regions. Here, we report an electrochemical sensing system based on magnetic nanoparticles that enable a quantitative and selective analysis of the methylated septin9 (mSEPT9) gene, which is considered a diagnostic marker in early stage colorectal cancer (CRC). Methylation levels of SEPT9 in CRC samples were successfully followed by the selective recognition ability of a related peptide nucleic acid (PNA) after hybridization with DNA fragments in human patients’ serums and plasma (n = 10). Moreover, this system was also adapted into a point-of-care (POC) device for a one-step detection platform. The detection of mSEPT9 demonstrated a limit of detection (LOD) value of 0.37% and interference-free measurement in the presence of branched-chain amino acid transaminase 1 (BCAT1) and SRY box transcription factor 21 antisense divergent transcript 1 (SOX21-AS1). The currently proposed functional platform has substantial prospects in translational applications of early CRC detection