Gold Nanoparticles Hold Promise for the Early Detection of Disease
News May 16, 2016
Since its inception, Strem Chemicals has focused on offering unique organometallic compounds for both academic and industrial research purposes. A series of nanomaterials, including metal nanoclusters, metal nanocolloids (organosols and hydrosols), metal nanopowders, metal nanoparticles, and magnetic fluids are now available from Strem Chemicals in the UK and Ireland.
Close relationships with leading researchers in the field have enabled Strem to stay abreast of the latest scientific advances in and regularly add novel chemicals to our product portfolio.
Multi-colour labelling of both fixed and living cells with fluorescent nanoparticles conjugated with biological ligands that specifically bind against certain cellular targets enables the recording of diffusion pathways in receptor cells. Uptake of nanoparticlesinto the vesicular compartments around the nucleus of cells can be used to label the cells so that their pathway and fate can be followed. The nanoparticles exhibit reduced photo bleaching as compared to traditional dyes and are passed on to daughter cells during cell division, therefore allowing for much longer term observation. Magnetic nanoparticles can also act as sensors for assessing how external stresses affect changes in intracellular biochemistry and gene expression.
Colloidal gold nanoparticles have been found to strongly enhance the native signals of chemical constituents in cells. Surface Enhanced Raman Spectroscopy (SERS) relies on this signal magnification and serves as a tool for ultra-sensitive monitoring of the intracellular distribution of these chemicals.
Colloidal gold bio functionalised Nano modules also have potential for use in enzyme multi-sensors. Gold nanoparticles coated with proteins have been used to detect conformation changes in the attached proteins via observation of colour changes. Strem is the first company in the world to be able to synthesize and stabilize high quality gold nanorods without the use of CTAB. Our ability to manufacture gold nanorods without CTAB/CTA+ will accelerate the adoption of these nanoparticle products for medical and surgical applications. In addition, our GNR products offer many features, supported by our patent-pending technical advances, that will offer benefits to the primary commercial users of gold nanoparticle products, biotech companies, who make gold Nano rod-enabled point-of-care, point-of-use and In-Vitro diagnostic test kit products.”
Early detection of disease remains a primary goal of the medical community. Nanotechnology holds great promise for enabling the achievement of this goal. Nanoparticles in particular have exhibited tremendous potential for detecting fragments of viruses, pre-cancerous cells, disease markers, and indicators of radiationdamage.
Gold coatings have made it possible to use toxic cobalt nanoparticles for biomedical applications. Gold coated ferromagnetic nanoparticles tagged with HIV antibodies may be able to detect virus particles left after completion of conventional drug therapy.
Metal nanoparticles in the form of dendrimers have also been functionalized with different biomolecules to detect specific proteins, antibodies, and other disease indicators. Fluorescent markers can also be attached to the dendrimers.
Biomolecule coated ultra small superparamagnetic iron oxide (USPIO) particles injected in the blood stream recognize target molecular markers present inside cells and induce a specific signal for detection by magnetic resonance imaging (MRI). This technology may allow for detection of individual cancer cells months or years earlier than traditional diagnostic tools, which require the presence of hundreds of cancer cells.
A nanoparticle-based bio barcode amplification assay (BCA) utilizes gold nanoparticles and magnetic micro particles attached to large numbers of DNA strands and antibodies for a specific disease marker. The marker binds to the nano- and micro particles forming a complex that is separated from the sample using a magnetic field.
Heating the complexes releases the DNA barcodes, which emit an amplified signal due to their large numbers. This BCA technology has been applied to the detection of markers for Alzheimer’s disease and is being investigated for numerous others.
Targeted drug delivery systems can convey drugs more effectively and/or more conveniently, increase patient compliance, extend the product life cycle, provide product differentiation, and reduce health care costs.
Delivery systems that rely on nanomaterials also allow for targeted delivery of compounds characterized by low oral bioavailability due to poor water solubility, permeability and/or instability and provide for longer sustained and controlled release profiles.
These technologies can increase the potency of traditional small molecule drugs in addition to potentially providing a mechanism for treating previously incurable diseases. The use of magnetic nanoparticles in targeted drug delivery systems is under investigation by several research groups.
Therapeutic drug molecules have been immobilized on the surface of magnetic nanoparticles or nanocrystals and directed to a specific target tissue using a magnetic field gradient. The drug is released by applying a radio frequency (RF) pulse.
Gold coated iron, nickel and cobalt ferromagnetic nanoparticles have been employed in this “tag and drag” approach. In hypothermal treatment, magnetic nanoparticles are directed to diseased tissue containing heat sensitive tumours. An ac magnetic field is applied such that the nanoparticles become heated, causing destruction of the cancerous cells.
More effective radiation therapy for tumour treatment can also be expected using metallic nanoparticles instead of, for example, magnetite. The nanoparticles allow the application of higher dosages of radiation at the tumour while sparing normal tissue.
Numerous other potential applications exist in the medical and pharmaceutical field for nanomaterials from Strem. Areas currently under investigation include gene therapy, antibacterial/antimicrobial agents for burn and wound dressings, repair of damaged retinas, artificial tissues, prosthetics, enhancing signals for magnetic resonance imaging examinations, and as radio frequency controlled switching of complex biochemical processes.
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