Biosensors nanomaterial

Susan M. Brozik, Biosensors Nanomaterials, Sandia National Laboratories, PO Box 5800, MS-0892, Albuquerque, New Mexico 87185, USA... 

In 1994, thiols were firstly used as stabilizers of gold nanoparticles [6a]. Thiols form monolayer on gold surface [18] and highly stable nanoparticles could be obtained. Purification of nanoparticles can be carried out, which makes chemical method of metal nanoparticles a real process for nanomaterial preparation. Various thiol derivatives have been used to functionalize metal nanoparticles [6b, 19]. Cationic and anionic thiol compounds were used to obtain hydrosols of metal nanoparticles. Quaternary ammonium-thiol compounds make the nanoparticle surface highly positively charged [20]. In such cases, cationic nanoparticles were densely adsorbed onto oppositely charged surfaces. DNA or other biomolecule-attached gold nanoparticles have been proposed for biosensors [21]. 

The material is presented in 17 chapters, covering topics such as trends in ion selective electrodes, advances in electrochemical immunosensors, modem glucose biosensors for diabetes management, biosensors based on nanomaterials (e.g. nanotubes or nanocrystals), biosensors for nitric oxide and superoxide, or biosensors for pesticides. 

Keywords Biosensor Lithography Microbiochip Microfabrication Molecularly imprinted polymer Nanocomposite Nanofabrication Nanomaterial Synthetic receptor... 

Chapters 1 to 5 deal with ionophore-based potentiometric sensors or ion-selective electrodes (ISEs). Chapters 6 to 11 cover voltammetric sensors and biosensors and their various applications. The third section (Chapter 12) is dedicated to gas analysis. Chapters 13 to 17 deal with enzyme based sensors. Chapters 18 to 22 are dedicated to immuno-sensors and genosensors. Chapters 23 to 29 cover thick and thin film based sensors and the final section (Chapters 30 to 38) is focused on novel trends in electrochemical sensor technologies based on electronic tongues, micro and nanotechnologies, nanomaterials, etc. 

The specific properties of novel nanomaterials as nanowires offer an excellent prospect for biological recognition surfaces in order to develop a more selective and sensitive biosensor technology [60-62],... 

Electrochemical behavior of nanomaterials as transducer for biosensors, immunosensors and chemical sensors. 

Nanomaterials can also be applied to glucose biosensors to enhance the properties of the sensors and, therefore, can lead to smaller sensors with higher signal outputs. Carbon nanotubes have been incorporated in previously developed sensors and seen to increase the peak currents observed by threefold.89 Platinum nanoparticles and single-wall carbon nanotubes have been used in combination to increase sensitivity and stability of the sensor.90,91 CdS quantum dots have also been shown to improve electron transfer from glucose oxidase to the electrode.92,93 Yamato et al. dispersed palladium particles in a polypyrrole/sulfated poly(beta-hydro-xyethers) and obtained an electrode response at 400 mV, compared to 650 mV, at a conventional platinum electrode.94... 

Biological functionalization of nanomaterials has become to be of significant interest in recent years owing to the possibility of developing detector systems. Noncovalent immobilization of biomolecules on carbon nanotubes motivated the use of the tubes as potentially new types of biosensor materials [207-210] (a review on carbon nanotube based biosensors was recently published by Wang [211]). So far, only limited work has been carried out with MWCNTs [207-210]. Streptavidin was found to adsorb on MWCNTs, presumably via hydro-phobic interactions between the nanotubes and hydrophobic domains of the proteins [210]. 

In addition to its contribution described above, nanoscience can provide an alternative step forward to promoting biomolecular-fluorescence detection. Recent advances in nanoscience permits innovative assembly and fiibrication of nanomaterials for use as advanced biosensor substrates in fluorescence detection. Therefore, nanoscience may offer a much simpler and convenient route in promoting biomolecular fluorescence detection, even when using as-grown nanomaterials without any downstream modifications following their synthesis. In order to design such substrates comprised of nanonaaterials, four key characteristics of the candidate nanoscale materials should be carefiilly considered ... 

The first important group of nanomaterials with application in sensors and biosensors field is represented by the CNTs [114], The nanodimensions, surface chemistry and electronic properties of CNT make this material an ideal candidate for chemical and biochemical sensing. There are two main types of CNTs (i) single-walled nanotubes (SWNTs) consisting of single graphite rolled seamlessly wrapped into a cylindrical tube (1-2 nm diameter) represents undoubtedly one of the more remarkable discoveries in the... 

Although different nanomaterials such as nanoparticles, nanowires and nanotubes are used for the construction of biosensor, this chapter is mainly devoted to the use of AuNPs for the construction of electrochemical biosensor and their analytical performances. Further, in this chapter we restrict ourselves in the electrochemical sensing of glucose, ascorbic acid, uric acid and dopamine derivatives using the AuNPs modified electrodes. 

This section deals with the ordered immobilization of AuNPs on the solid surface or electrodes. Attachment of AuNPs onto an electrode surface is very important task in developing an electrochemical biosensor. There are numerous approaches to fabricate nanomaterials on electrode surfaces, depending on the exact material and substrate. The modified electrodes usually exhibit different electrochemical and electrocatalytic characteristics even if there is a slight change in the modification procedure. Therefore, it is necessary to discover different electrode materials as well as novel attachment approaches for AuNPs [42], Generally, AuNPs modified electrode surfaces can be prepared in three major ways ... 

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