Nanoparticle-based sensing

Different strategies of electrochemical sensing have been used for DNA electrochemical detection (1) direct DNA electrochemistry, (2) indirect DNA electrochemistry, (3) DNA-specific redox indicator detection, (4) DNA-mediated charge transport, and (5) nanoparticle-based electrochemistry amplification. 

Nanoparticle-Enhanced Electron Conduction-Based Sensing... 

SILICA NANOPARTICLES BASED SELF-ORGANIZED SENSING... 

PEBBLEs are water-soluble nanoparticles based on biologically inert matrices of cross-linked polymers, typically poly(acrylamide), poly(decylmethacrylate), silica, or organically modified silicates (ORMOSILs), which encapsulate a fluorescent chemo-sensor and, often, a reference dye. These matrices have been used to make sensors for pH, metal ions, as well as for some nonionic species. The small size of the PEBBLE sensors (from 20 to 600 nm) enables their noninvasive insertion into a living cell, minimizing physical interference. The semipermeable and transparent nature of the matrix allows the analyte to interact with the indicator dye that reports the interaction via a change in the emitted fluorescence. Moreover, when compared to naked chemosensors, nanoparticles can protect the indicator from chemical interferences and minimize its toxicity. Another important feature of PEBBLEs, particularly valuable in intracellular sensing applications, is that the polymer matrix creates a separate... 

Silica Nanoparticles Based Self-Organized Sensing Agents 367... 

Last, but not least, full application of QDs in chemical sensors would require the immobilization of the nanoparticles into appropriate solid supports in order to develop reliable active phases (able to provide, for instance, convenient fiber optic-based sensing applications). Although only a few reports have been published so far regarding the trapping of the QDs in solid matrices, some important steps have already started towards the realization of the potential of these technologies. There is still plenty of room for further development in all those directions. 

Implementing nanoparticles in biosensing applications relies heavily on the nano-paiticle s core composition, surface functionalization, sensing mechanism, and modality. The aforementioned aspects in the design of nanoparticle-based sensors provide the main challenge to the development of novel nanoparticle-based systems to replace fluorescent molecular indicators such as DCFH for sensing ROS... 

The other fundamental advantage of gold nanoparticles-based electrochemical DNA biosensors is the development of amplification routes for the DNA sensing events. According to Willner etal. [7], the concept of the amplified detection of DNA using gold nanoparticles... 

Lakard et al. have described HRP modified PANI nanoparticles-based biosensor for sensing [159]. This biosensor format exhibits improved enzyme deposition and improved signal-to-noise ratio. There is a strong relationship between nano-dimension and biosensing performance. 

Huang CC, Chang HT (2006) Selective gold-nanoparticle-based tum-on fluorescent sensors for detection of mercury(II) in aqueous solution. Anal Chem 78 8332-8338 He X, Liu H, Li Y et al (2005) Gold nanoparticle-based fluorometric and colorimetric sensing of copper(II) ions. Adv Mater 17 2811-2815... 

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