Biosensors for Nucleic Acids

Advancements in the area of optical biosensors for nucleic acid determinations have been substantial and many design concepts and surface chemistries have been explored. A practical solution that provides for all of the desired biosensor attributes - reusability, robustness, reliability, selectivity, sensitivity and speed of response - in a single device has not yet been... 

Nugen SR, Asiello PJ, Connelly JT, Baeumner AJ (2009) PMMA biosensor for nucleic acids with integrated mixer and electrochemical detection. Biosens Bioelectron 24 2428-2433... 

Results on DNA-based biosensors will be presented they have been used mainly for two kind of applications 1) for the determination of low-molecular weight compounds witlr affinity for nucleic acids and 2) for the detection of hybridization reaction. 

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. 

The classical methods on DNA detection are time-consuming and labor-intensive. However, wide-scale genetic testing requires the development of fast, inexpensive, and sensitive miniaturized devices. Thus, biosensors offer a promising alternative for faster, cheaper, and simpler detection protocols for nucleic acid analysis. These biosensors commonly rely on the immobilization of double-stranded DNA (dsDNA), single-stranded DNA (ssDNA), or an oligonucleotide... 

The immobilization of the hyperbranched spherical structures onto physical transducers greatly increases the binding capacity of the surface and leads to enhanced sensitivity and extended linearity of biosensors. Nucleic acid dendrimers were prepared and their amplification properties for the detection of DNA were examined using mass-sensitive transducers [45, 46]. Antibodies... 

The initial hurdle to overcome in the biosensor application of a nucleic acid is that involving its stable attachment on a transducing element which commonly includes a metallic electrode. In the first part of this chapter, we wish to introduce our approach for DNA immobilization (Scheme 1). A detailed characterization of the immobilization chemistry is also presented. In the second part, we follow the development of work from our laboratory on chemical sensor applications of the DNA-modified electrode involving a biosensor for DNA-binding molecules and an electrochemical gene sensor. 

Cell components or metabolites capable of recognizing individual and specific molecules can be used as the sensory elements in molecular sensors [11]. The sensors may be enzymes, sequences of nucleic acids (RNA or DNA), antibodies, polysaccharides, or other reporter molecules. Antibodies, specific for a microorganism used in the biotreatment, can be coupled to fluorochromes to increase sensitivity of detection. Such antibodies are useful in monitoring the fate of bacteria released into the environment for the treatment of a polluted site. Fluorescent or enzyme-linked immunoassays have been derived and can be used for a variety of contaminants, including pesticides and chlorinated polycyclic hydrocarbons. Enzymes specific for pollutants and attached to matrices detecting interactions between enzyme and pollutant are used in online biosensors of water and gas biotreatment [20,21]. 

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