Chitosan/Ionic Liquid Composite Electrode for Electrochemical Monitoring of the Surface-Confined Interaction Between Mitomycin C and DNA

Electrochemistry as a Powerful Tool for Investigations of Antineoplastic Agents: A Comprehensive Review

Cancer is most frequently treated with antineoplastic agents (ANAs) that are hazardous to patients undergoing chemotherapy and the healthcare workers who handle ANAs in the course of their duties. All aspects related to hazardous oncological drugs illustrate that the monitoring of ANAs is essential to minimize the risks associated with these drugs. Among all analytical techniques used to test ANAs, electrochemistry holds an important position. This review, for the first time, comprehensively describes the progress done in electrochemistry of ANAs by means of a variety of bare or modified (bio)sensors over the last four decades (in the period of 1982-2021). Attention is paid not only to the development of electrochemical sensing protocols of ANAs in various biological, environmental, and pharmaceutical matrices but also to achievements of electrochemical techniques in the examination of the interactions of ANAs with deoxyribonucleic acid (DNA), carcinogenic cells, biomimetic membranes, peptides, and enzymes. Other aspects, including the enantiopurity studies, differentiation between single-stranded and double-stranded DNA without using any label or tag, studies on ANAs degradation, and their pharmacokinetics, by means of electrochemical techniques are also commented. Finally, concluding remarks that underline the existence of a significant niche for the basic electrochemical research that should be filled in the future are presented.

Electrochemical DNA biosensors developed for the monitoring of biointeractions with drugs: a review

The interaction of drugs with DNA is important for the discovery of novel drug molecules and for understanding the therapeutic effects of drugs as well as the monitoring of side effects. For this reason, many studies have been carried out to investigate the interactions of drugs with nucleic acids. In recent years, a large number of studies have been performed to electrochemically detect drug-DNA interactions. The fast, sensitive, and accurate results of electrochemical techniques have resulted in a leading role for their implementation in this field. By means of electrochemical techniques, it is possible not only to demonstrate drug-DNA interactions but also to quantitatively analyze drugs. In this context, electrochemical biosensors for drug-DNA interactions have been examined under different headings including anticancer, antiviral, antibiotic, and central nervous system drugs as well as DNA-targeted drugs. An overview of the studies related to electrochemical DNA biosensors developed for the detection of drug-DNA interactions that were reported in the last two decades in the literature is presented herein along with their applications and they are discussed together with their future perspectives.

Sequence-Specific Electrochemical Genosensor for Rapid Detection of blaOXA-51-like Gene in Acinetobacter baumannii

Acinetobacter baumannii (A. baumannii) are phenotypically indistinguishable from the Acinetobacter calcoaceticus−A. baumannii (ACB) complex members using routine laboratory methods. Early diagnosis plays an important role in controlling A. baumannii infections and this could be assisted by the development of a rapid, yet sensitive diagnostic test. In this study, we developed an enzyme-based electrochemical genosensor for asymmetric PCR (aPCR) amplicon detection of the blaOXA-51-like gene in A. baumannii. A. baumanniiblaOXA-51-like gene PCR primers were designed, having the reverse primer modified at the 5′ end with FAM. A blaOXA-51-like gene sequence-specific biotin labelled capture probe was designed and immobilized using a synthetic oligomer (FAM-labelled) deposited on the working electrode of a streptavidin-modified, screen-printed carbon electrode (SPCE). The zot gene was used as an internal control with biotin and FAM labelled as forward and reverse primers, respectively. The blaOXA-51-like gene was amplified using asymmetric PCR (aPCR) to generate single-stranded amplicons that were detected using the designed SPCE. The amperometric current response was detected with a peroxidase-conjugated, anti-fluorescein antibody. The assay was tested using reference and clinical A. baumannii strains and other nosocomial bacteria. The analytical sensitivity of the assay at the genomic level and bacterial cell level was 0.5 pg/mL (1.443 µA) and 103 CFU/mL, respectively. The assay was 100% specific and sensitive for A. baumannii. Based on accelerated stability performance, the developed genosensor was stable for 1.6 years when stored at 4 °C and up to 28 days at >25 °C. The developed electrochemical genosensor is specific and sensitive and could be useful for rapid, accurate diagnosis of A. baumannii infections even in temperate regions.

Graphene-Oxide and Ionic Liquid Modified Electrodes for Electrochemical Sensing of Breast Cancer 1 Gene

Graphene-oxide and ionic liquid composite-modified pencil graphite electrodes (GO-IL-PGEs) were developed and used as a sensing platform for breast cancer 1 (BRCA1) gene detection. The characterization of GO-IL modified electrodes was executed by scanning electron microscopy (SEM), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The nucleic-acid hybridization was monitored by a differential pulse voltammetry (DPV) technique by directly measuring the guanine oxidation signal without using any indicator. The effects of the IL concentration, the probe concentration, and the hybridization time were optimized to the biosensor response. The limit of detection (LOD) was calculated in the concentration range of 2–10 μg/mL for the BRCA1 gene and found to be 1.48 µg/mL. The sensitivity of the sensor was calculated as 1.49 µA mL/µg cm². The developed biosensor can effectively discriminate the complementary target sequence in comparison to a three-base-mismatched sequence or the non-complementary one.

Electrochemical Investigation of Curcumin-DNA Interaction by Using Hydroxyapatite Nanoparticles-Ionic Liquids Based Composite Electrodes

Hydroxyapatite nanoparticles (HaP) and ionic liquid (IL) modified pencil graphite electrodes (PGEs) are newly developed in this assay. Electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and cyclic voltammetry (CV) were applied to examine the microscopic and electrochemical characterization of HaP and IL-modified biosensors. The interaction of curcumin with nucleic acids and polymerase chain reaction (PCR) samples was investigated by measuring the changes at the oxidation signals of both curcumin and guanine by differential pulse voltammetry (DPV) technique. The optimization of curcumin concentration, DNA concentration, and the interaction time was performed. The interaction of curcumin with PCR samples was also investigated by gel electrophoresis.

A New Electrochemical Sensor for Direct Detection of Purine Antimetabolites and DNA Degradation

The development of a reliable electrochemical sensor using a hybrid nanocomposite consisting of ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate) functionalized graphene oxide (GrO-IL) and gold nanoparticles (AuNPs) stabilized by chitosan (Chit) was described. The new sensor, labelled as GrO-IL-AuNPs-Chit/CSE, exhibited an improved electrocatalytic response to cancer drugs such as purine antimetabolites (6-thioguanine, 6-mercaptopurine, and azathioprine) in a wide concentration range with a low detection limit (20-40 nmol·L^-1, S/N = 3), and satisfactory recoveries (97.1-103.0%). The sensor has been also successfully used for cyclic voltammetric study of a salmon sperm double-stranded DNA degradation and DNA-6-mercaptopurine interaction in aqueous solutions (pH 7.4).

Electrochemical DNA Sensor Based on Carbon Black-Poly(Neutral Red) Composite for Detection of Oxidative DNA Damage

Voltammetric DNA sensor has been proposed on the platform of glassy carbon electrode covered with carbon black with adsorbed pillar[5]arene molecules. Electropolymerization of Neutral Red performed in the presence of native or oxidatively damaged DNA resulted in formation of hybrid material which activity depended on the DNA conditions. The assembling of the surface layer was confirmed by scanning electron microscopy and electrochemical impedance spectroscopy. The influence of DNA and pillar[5]arene on redox activity of polymeric dye was investigated and a significant increase of the peak currents was found for DNA damaged by reactive oxygen species generated by Cu²⁺/H₂O₂ mixture. Pillar[5]arene improves the electron exchange conditions and increases the response and its reproducibility. The applicability of the DNA sensor developed was shown on the example of ascorbic acid as antioxidant. It decreases the current in the concentration range from 1.0 μM to 1.0 mM. The possibility to detect antioxidant activity was qualitatively confirmed by testing tera infusion. The DNA sensor developed can find application in testing of carcinogenic species and searching for new antitumor drugs.

An Impedimetric Biosensor Based on Ionic Liquid-Modified Graphite Electrodes Developed for microRNA-34a Detection

In the present work, an impedimetric nucleic acid biosensor has been designed for the purpose of detection of microRNA (miRNA). Ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate (IL))-modified chemically activated pencil graphite electrodes (PGEs) were used for the sensitive and selective detection of miRNA-34a. After covalent activation of the PGE surface using covalent agents (CAs), the ionic liquid (IL) was immobilized onto the surface of the chemically activated PGE by passive adsorption. The electrochemical and microscopic characterization of the IL/CA/PGEs was performed by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and scanning electron microscopy (SEM). DNA probe concentration, miRNA target concentration, and also the hybridization time and wet adsorption time were optimized by using the EIS technique. Then, the hybridization occurred between specific DNA probes and miRNA-34a was immobilized onto the surface of the IL/CA/PGEs. The impedimetric detection of miRNA-DNA hybrid was performed by EIS. The detection limit (DL) was calculated in a linear concentration range of 2⁻10 µg/mL miRNA-34a target, and it was found to be 0.772 µg/mL (109 nM) in phosphate buffer solution (PBS) and 0.826 µg/mL (117 nM) in diluted fetal bovine serum (FBS). The selectivity of impedimetric biosensor for miRNA-34a was also tested against to other non-complementary miRNA sequences both in buffer media, or diluted FBS.

Non-Enzymatic Electrochemical Sensing of Malathion Pesticide in Tomato and Apple Samples Based on Gold Nanoparticles-Chitosan-Ionic Liquid Hybrid Nanocomposite

Malathion (MLT) is an organophosphorous type pesticide and having seriously high toxicity and electrochemical platforms for rapid, simple, inexpensive and sensitive determination of pesticides is still a special concern. This paper describes a simple preparation of a composite film consisting of ionic liquid (IL), chitosan (CS) and electrochemically synthesized gold nanoparticles (AuNPs) on single use pencil graphite electrodes (PGEs). The microscopic and electrochemical characterization of AuNP-CS-IL/PGE was studied using scanning electron microscopy, cyclic voltammetry and electrochemical impedance spectroscopy. This fabricated surface was then explored for the first time as a sensing matrix for the non-enzymatic electrochemical sensing of malathion by cyclic voltammetry and square wave voltammetry measurements. The proposed AuNP-CS-IL/PGE showed excellent characteristics and possessed remarkable affinity for malathion. The voltammetric current response exhibited two linear dynamic ranges, 0.89–5.94 nM and 5.94–44.6 nM reflecting two binding sites, with a detection limit of 0.68 nM. The method was applied in real sample analysis of apple and tomato. The results demonstrate the feasibility of AuNP-CS-IL-modified electrodes for simple, fast, ultrasensitive and inexpensive detection of MLT.

Development of Ionic Liquid Modified Disposable Graphite Electrodes for Label-Free Electrochemical Detection of DNA Hybridization Related to Microcystis spp

In this present study, ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate (IL)) modified pencil graphite electrode (IL-PGEs) was developed for electrochemical monitoring of DNA hybridization related to Microcystis spp. (MYC). The characterization of IL-PGEs was performed using microscopic and electrochemical techniques. DNA hybridization related to MYC was then explored at the surface of IL-PGEs using differential pulse voltammetry (DPV) technique. After the experimental parameters were optimized, the sequence-selective DNA hybridization related to MYC was performed in the case of hybridization between MYC probe and its complementary DNA target, noncomplementary (NC) or mismatched DNA sequence (MM), or and in the presence of mixture of DNA target: NC (1:1) and DNA target: MM (1:1).