Nucleic acid biosensing

Several recent reports describe nucleic acid biosensing methods that rely on electroactive reporter groups that are not DNA-binding molecules. 

The applications of nanoparticles in biosensors can be classified into two categories according to their functions (1) nanoparticle-modified transducers for bioanalytical applications and (2) biomolecule-nanoparticle conjugates as labels for biosensing and bioassays. We intend to review some of the major advances and milestones in biosensor development based upon nanoparticle labels and their roles in biosensors and bioassays for nucleic acids and proteins. Moreover, we focus on some of the key fundamental properties of certain nanoparticles that make them ideal for different biosensing applications. 

A very broad research activity in recent years is focused on investigation of possibilities of applications of nucleic acids for biosensing, especially DNA. As DNAs in organisms function as carrier of genetic information, for biosensors employing DNA as molecular recognition element a name genosensors appears recently in analytical literature. 

The development and application of biosensors has been discussed in several reviews [125, 126]. For instance, fabrication of cholesterol biosensors relies on the immobilization of cholesterol oxidase and cholesterol esterase onto CNTs, while horseradish peroxidase and flavocytochrome P450scc are also used for the same reason [125, 126]. Beyond the biosensing field, carbon nanotubes are also used as carriers for peptide, nucleic acid and drug delivery, due to their intrinsic property to cross cell membranes [102, 124]. The fact that the functionalized CNTs (f-CNTs) are not immunogenic and low-toxic opens the pathway for more research in the field of CNT-abetted drug delivery [102]. 

The last example is based on the interaction between a new receptor (ap-tamer) able to interact with a specific protein and represents an example of nucleic acid-protein interaction. The aptamers can represent an alternative to an antibody-based sensor and are an interesting challenge in biosensing research. 

The topics discussed in the book include electrochemical detection of DNA hybridization based on latex/gold nanoparticles and nanotubes nanomaterial-based electrochemical DNA detection electrochemical detection of microorganism-based DNA biosensor gold nanoparticle-based electrochemical DNA biosensors electrochemical detection of the aptamer-target interaction nanoparticle-induced catalysis for DNA biosensing basic terms regarding electrochemical DNA (nucleic acids) biosensors screen-printed electrodes for electrochemical DNA detection application of field-effect transistors to label-free electrical DNA biosensor arrays and electrochemical detection of nucleic acids using branched DNA amplifiers. 

There are a variety of methods to detect the DNA content of food, which can be used to unequivocally identify the nature of the product [4]. Among the various systems for nucleic acid detection, electrochemical DNA analysis can involve direct detection based on a guanine signal (label-free) [5] or an electrocatalytic mechanism (label-based). Quantum dots (QDs) [6,7], metal nanoparticles (NPs) [8,9], enzymes [10,11], and metal complexes [12, 13] can be employed as labels. This chapter focuses on electrochemical biosensing systems based on DNA hybridization events, which offer novel routes for food safety and security applications. Particularly, it describes in detail different approaches reported in the latest years on the immobilization of oligonucleotides on electrochemical transducers for sensing of various compounds with interest in food industry. In addition, some interesting applications in other fields that can easily be extended to that of food are also included. 

Utilize a biochemical mechanism for recognition. They are responsible for binding the analyte of interest to the sensor surface for the measurement. Bioreceptors can generally be classified into five major categories enzyme, antibody/antigen, nucleic acid/DNA, cellular structure/ceU, and biomimetic. The sampling component of a biosensor contains a biosensitive layer that can contain bioreceptors or be made of bioreceptors cova-lendy attached to the transducer. The most common forms of bioreceptors used in biosensing are based on ... 

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