nanotechnology

nanotechnology

 

Electrospinning Nanofibers for Water Treatment

Electrospinning is a highly versatile technique that can be used to create ultrafine fibres of various polymers and other materials, with diameters ranging from a few micrometers down to tens of nanometres. The nonwoven webs of fibers formed through this process typically have high specific surface areas, nano-scale pore sizes, high and controllable porosity and extreme flexibility with regard to the materials used and modification of the surface chemistry of the fibres. A combination of these features is utilized in the application of electrospun nanofibres to a variety of water treatment applications, including filtration, solid phase extraction and reactive membranes read more ...

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Reverse Osmosis

The membrane separation technologies of reverse osmosis (hyperfiltration) and nanofiltration are important in water treatment applications. Reverse osmosis is based on the basic principle of osmotic pressure, while nanofiltration makes use of molecule size for separation. Recent advances in the field of nanotechnology are opening a range of possibilities in membrane technologies. These include: new membrane preparation and cleaning methods, new surface and interior modification possibilities, the use of new nanostructured materials, and new characterization techniques read more ...

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Nanofiltration for Water and Wastewater Treatment

Nanofiltration is a new type of pressure driven membrane process and used between reverse osmosis and ultrafiltration membranes. The most different speciality of nanofiltration membranes is the higher rejection of multivalent ions than monovalent ions. Nanofiltration membranes are used in softening water, brackish water treatment, industrial wastewater treatment and reuse, product separation in the industry, salt recovery and recently desalination as two pass nanofiltration system read more ...

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Nanofibers and Nanobiocides in Water Purification

Electrospun nanofibers and nanobiocides show potential in the improvement of water filtration membranes. Biofouling of membranes caused by the bacterial load in water reduces the quality of drinking water and has become a major problem. Several studies showed inhibition of these bacteria after exposure to nanofibers with functionalized surfaces. Nanobiocides such as metal nanoparticles and engineered nanomaterials are successfully incorporated into nanofibers showing high antimicrobial activity and stability in water read more ...

from Nanotechnology in Water Treatment Applications by Cloete, TE et al. (2010)

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Nanotechnology and Nanosensors

Nanotechnology will play an important role in future biosensor development. Nanotechnology is now making possible development of in vivo sensors, i.e. nano-sized devices envisioned to be ingested or injected where they could act as reporters of in vivo concentrations of key analytes. These engineered nanoparticle devices imbedded in the cytosol of individual tissue specific cells will be capable of transmitting recognition events, that is, the binding to biorecognition elements of target analytes of clinical relevance to an external data capture system. Nanosensors will enable compartmental analyses of metabolite levels and metabolic activity. Nanosensor prototypes have been expressed in Yeast and in mammalian cell cultures for determination of carbohydrate homeostasis in living cells with subcellular resolution. Nanosensors can be selectively expressed under the control of tissue specific promoters. The clinical relevance arising from constant, real-time metabolic vigilance via sensor based ligand specific biorecognition elements is immense. Virus-based nanoparticles have been developed for tumor specific recognition, targeting, imaging and destruction.

Of particular note, DNA conjugate materials have been prepared which can recognize DNA fragments with one-base specificity for reliable genotyping of single nucleotide polymorphisms, while bacterial magnetic particles have been integrated into functional nanomaterials by assembling enzymes, antibodies and receptors onto nano-sized bacterial magnetic particles for use in applications such as determination of human insulin.

The emerging ability to control patterns of matter on the nanometer length scale can be expected to lead to entirely new spatial positioning schemes of biorecognition elements using a variety of new materials. Although current technologies such as microstructure fabrication, surface modification, integration of detection and optimization of chemistry can not effectively complete with current, well established detection instrumentation, the need for high throughput diagnostic/detection methods will continue. If pursued, array technology should open the door for commercializing sensor platforms utilizing a variety of biorecognition elements for general diagnostic/detection purposes.

from Chambers et al. in Curr. Issues Mol. Biol. (2008) 10: 1-12
abstract     full article pdf

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Biosensors

A biosensor is a compact analytical device or unit incorporating a biological or biologically derived sensitive recognition element integrated or associated with a physio-chemical transducer. Since the first biosensor was developed many new biosensors have been studied and the range of applications extended.

Molecular recognition is central to biosensing. Initially, biosensor recognition elements were isolated from living systems. However, many biosensor recognition elements now available are not naturally occurring but have been synthesized in the laboratory. The sensing of targets, i.e. analytes of interest, is being influenced by the availability of new engineered binding proteins. Employing the techniques of modern biotechnology, it is now possible to construct DNA polynucleotides at will, thus opening new possibilities for the generation of biosensor recognition elements arising from paths not taken by nature.

In the future, the ability to "recognize" and "detect" electrically and magnetically will be radically transformed. The emergence of magnetoelectronics is a promising new platform technology for biorecognition element/sensor development.

from Chambers et al. in Curr. Issues Mol. Biol. (2008) 10: 1-12
abstract     full article pdf

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