Transducer platform

We have developed a new strategy based on the adsorption behaviour of nanostructured materials towards HMIs to enhance the selectivity and sensitivity of electrochemical transducing platforms. Various nanostructured materials which possess higher adsorption capacity or different adsorption behaviour toward HMIs have been designed. In this chapter, our recent progress in application of nanostructured materials as modifiers of electrodes in electrochemical detection of HMIs will be introduced. We have combined electrochemical experiments, adsorption measurements, and computational calculation to show this new route to realize the improved selectivity and sensitivity in electrochemical sensing of toxic HMIs. 

One of the most promising applications of MIPs is the fabrication of chips with microarrays containing several selective polymers against different targets. Fabrication of such platforms will extend the application and the commercial impact of such materials to many different areas where multianalyte capability is a must. Nevertheless, further efforts are still needed to optimize fabrication of localized polymer structures, avoiding problems related to long term stability of the biomi-metic material, MIP deposition, and transducer coupling. 

In aspect of chip-based technology, electrochemical genosensors based on different materials and transducers have been recently developed in response to clinical demand of giving promising results [18-25]. Different sensor technologies provide a unique platform in order to immobilize molecular receptors by adsorption, crosslinking or entrapment, complexation, covalent attachment, and other related methods on nanomaterials [5,7,26]. 

GEC-based platforms are useful and versatile transducer materials for electrochemical DNA genosensing of amplicon food pathogens. 

GEC based platforms are useful and versatile transducer materials for electrochemical immunosensing of food residues. Graphite-epoxy composites (GEC) and biocomposites (GEB), widely studied by our research group, show excellent transducing features for the detection of atrazine and sulfo-drugs based on electrochemical immunosensing. 

Recently, an impressive number of inventive designs of DNA-based electrochemical sensing are emerging. These types of sensors combine nucleic acid layers with electrochemical transducers to produce a biosensor and promise to provide a simple, accurate and inexpensive platform for patient diagnosis. 

The biosensors can be divided into nonlabelled or label-free types, which are based on the direct measurement of a phenomenon occurring during the biochemical reactions on a transducer surface and labelled, which relies on the detection of a specific label. Research into label-free biosensors continues to grow [13] however labelled ones are more common and are extremely successful in a multitude of platforms. 

Fig. 19 The sensor can be separated into three main parts. 1 A V-grooved auxiliary support, where the optical fibers are fixed, 2 the exchangeable transducer based on curved ARROW waveguides, where the membrane is deposited and 3 a connection platform, which allows the alignment of the transducer waveguides to the optical fibers, which are fixed in the auxiliary support by the aid of two microfabricated channels at both sides of the surface...

In conclusion, the proposed technologically improved IWAO made evident its appropriateness as a versatile platform for the development of ion-selective optical sensors, depending on the membrane composition, which also permits disposable transducers to be obtained. 

The very large absorption cross-sections of Au nanoparticles give rise to photothermal effects, that is, an increase in local temperature upon plasmon resonance excitation. The concept of Au nanoparticles as photothermal transducers has inspired numerous efforts to develop biomedical applications such as localized hyperthermal therapy,63-65 photothermal contrast agents,66 and optothermally controlled drug release,67-69 and also novel platforms for information storage.70... 

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