Currently several conventional identification techniques hav

Currently, several conventional identification techniques have been established such as polymerase chain reaction (PCR) [8], culture and colony counting [9], immunological techniques [10] and fluorescence-based assays using organic dye molecules [11]. The majority of these approaches is laborious, complex, time consuming, and lack the necessary levels of detectability and specificity towards the target [12]. Therefore, new, rapid, selective and sensitive detection techniques are required in clinical diagnosis, disease control, environmental monitoring and food safety. DNA biosensor technologies are rapidly developing as an alternative to the classical gene assays, due to the advantages of low cost, rapid analysis time, simplicity of operation, and possibility of miniaturization [13]. Moreover, it is a device that combines a DNA probe consisting of a biological recognition agent and a single-stranded DNA with a transducer. The selectivity of this device is due to the former, while its sensitivity is provided by the latter [14]. Biosensors take advantage of hybridization events to detect target DNA sequences [15]. Nucleic bcrp inhibitor based techniques are widely used for analytical applications due to their powerful recognition properties [16,17]. Selection of the nucleic acid for a DNA-based biosensor mainly depends on the event to be sensed. The main purpose of the biosensor is to detect a DNA sequence using a single-stranded DNA with a short oligonucleotide as the biosensing element. Several aspects that are crucial in the development of hybridization biosensors are sensitivity, detection of low concentrations of DNA and ability to detect a point mutation. Traditional methods of detecting the hybridization event are too slow and need special preparation. Thus, there is great interest in developing biosensors based on electrochemical hybridization. The use of nanoparticles (NPs) in biosensors has gained importance as an emerging area of research. The integration of NPs into biodevices has been reported by several researchers [18–21]. Nanobiosensors have been invented for the specific detection of biological molecules, e.g., nucleic acids [22], proteins [23] and enzymes [24] and as well as infectious agents [25]. The nanostructures have great advantages including high surface area, nontoxicity, good environmental acceptability, inexpensive, electrochemical activity and high electron communication features. Zinc oxide (ZnO) nanoparticles are one of the most important nanomaterials due to their unique electronic, metallic and structural characteristics [26]. Most nanoparticle-sensing research has focused on the ability of surface-confined ZnO to promote electron-transfer reactions with electroactive species. Electrochemical biosensors have taken great advantage of NPs to increase the surface area of the electrode, and to enhance electronic properties and electrocatalytic activity in order to improve their speed, detection ability and selectivity [18]. Ionic liquids (ILs) consist of large organic cations and various kinds of anions that exist in the liquid state at high temperatures of more than 100°C [27,28]. ILs have been receiving increased attention due to their unique chemical and physical properties, such as high chemical and thermal stability, negligible vapor pressure, high ionic conductivity, low toxicity, and ability to dissolve a wide range of organic and inorganic compounds [29,30]. ILs are extensively used as modifiers on electrode surfaces in the fabrication of gas sensors [31] and biosensors [32] due to their unique electrochemical properties, such as high ionic conductivity and relatively wide electrochemical window. Moreover, ILs also hold great promise for green chemistry applications in general and for electrochemical applications in particular. Chitosan (CHIT) as a biocompatible polymer was selected for the application in this study due to its low-cost, hydrophilicity, nontoxicity, and excellent film-forming ability. The combination of CHIT–ILs as a composite material has great potential in the application of electrochemical biosensors.