Additional Bioaffinity Nanoprobes == == 2.4.1. such as surface plasmon resonance (SPR) analysis, Fluorescence Resonance Energy Transfer (FRET) measurements, circular dichroism, and flow cytometry, that are used to evaluate the efficacy of bioaffinity nanoprobes. Additionally, it discusses advances in the development and application of Bay K 8644 biosensors in monitoring foodborne pathogens. Keywords:aptamer, nanoprobe, biosensor, bioaffinity, food safety == 1. Introduction == Food safety has become a global concern, given the frequency and severity of foodborne disease outbreaks recently, and the grave effects associated with them. Most of these outbreaks are caused by foodborne pathogens, which are bacteria, viruses, and parasites that contaminate food, causing diseases and in some cases deaths. Some of the predominant foodborne pathogens includeListeria monocytogenes,Campylobacter,Staphylococcus aureus,Salmonella typhimurium,andEscherichia coli[1]. The advancement of food supply chains, which has become a giant network connected to all parts of the world, makes the spread of foodborne illnesses more rapid and the strain on socio-economic development disastrous. Although there have been great advancements in the methods used to detect pathogens, there are Bay K 8644 still increasing outbreaks of foodborne diseases showing that the methods of analysis are no longer enough. The conventional culture-based methods are very cheap and easy to use but take up to several days to produce results and require extra biochemical or molecular tests to confirm that the species match the pathogen of interest, making them highly unsuitable for on-site detection [2]. Other methods have also been developed, such as the polymerase chain reaction (PCR), nucleic acid, and immunoassay-based methods. These methods are able to fix the time constraint of the culture-based methods but are usually expensive and require specific reagents, complicated sample pretreatment, and experienced personnel for the analysis, making the possibility of commercialization nearly impossible [3,4]. Hence, the urgent need for inexpensive, easy-to-use, but accurate, and rapid detection methods that do not require specialized expertise or equipment to run. Nanosensors, which are a product of biosensor technology incorporated into nanotechnology, are the newest and most advanced detection technology being developed by scientists [4,5]. A nanosensor is basically a compact analytical device with dimensions below 100 nanometers (nm) that Rabbit polyclonal to STK6 detects the presence of biomolecules and nanoparticles or monitors physical and chemical parameters on a nanoscale. It can be a sensor with bioreceptor platforms or a biosensor with an added nanomaterial (NM) component to enhance sensitivity and efficiency [6,7,8]. Nanosensors incorporating additional nanomaterials offer advantages such as high absorption capacity, improved thermal stability, presence of surface-activated functional groups, large surface area, and excellent surface reactivity [9]. There are three main stages in all nanosensing methods: the recognition element, also known as the bioaffinity probe, detects the target by forming a complex with it. The transducer converts the target recognition event into a measurable signal, such as an electrochemical, colorimetric, impedimetric, or voltammetric signal. A third element manipulates the converted signal into a format that can be easily displayed or interpreted by the analyst [10]. The success of a nanosensor largely depends on the selectivity combined with the sensitivity and specificity of the recognition element, overall stability, limit of detection, cost, response time, shelf life, linearity, recyclability, and hysteresis [11]. Since foodborne pathogens are usually present in trace quantities, the bioreceptor of choice for the nanosensor must possess a high affinity towards the target to be able to detect it even in minute quantities. For this reason, biomolecules such as antibodies, aptamers, enzymes, cells, and proteins are preferred as bioaffinity probes in the nanosensors or nano-biosensors [12]. In order to analyze the real-time performance of these bioaffinity probes, certain techniques have been designed. These analytical approaches consist of Surface Plasmon Resonance (SPR), Circular Dichroism (CD), Flow Cytometry (FC), and Fluorescence Resonance Energy Transfer (FRET) measurements, and they are used to study the interactions between these bioaffinity probes Bay K 8644 and their targets. == 2. Overview of Bioaffinity Nanoprobes == Bioaffinity nanoprobes are biomolecules that serve as bioreceptors in nanosensors. These molecules bind to the target to create a reaction that can be converted into an understandable signal to the analyst. These molecules include antibodies, aptamers, enzymes, and non-antibody binding proteins. == 2.1. Antibodies == Antibodies, which are also known as immunoglobulins (Ig), are defined.