Updated: January 31, 2001
N A N O P R O B E S E - N E W S
Vol. 2, No. 1 January 31, 2001
This monthly newsletter is keep you informed about techniques to improve your immunogold labeling, highlight interesting articles and novel metal nanoparticle applications, and answer your questions. We hope you enjoy it and find it useful.
Have questions, or issues you would like to see addressed in the next
issue? Let us know by e-mailing tech@nanoprobes.com.
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A recent discussion on the MSA microscopy listserver generated many ideas and suggestions for optimizing your TEM immmunolabeling, as well as explanations for why some antibodies work better than others. Read about the factors that can affect labeling performance of both primary and secondary antibodies, and how to test your labeling effectively before proceeding to a full TEM experiment.
Full details: www.nanoprobes.com/TechIEM.html
More technical help for Nanoprobes products: www.nanoprobes.com/Tech.html
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How is Nanogold labeling different from colloidal gold labeling? How do you get the best results from it? Our Guide to Gold Cluster Labeling shows you the process step-by-step, with all the factors that can affect your labeling reaction described and explained. The Guide includes the UV/visible spectra of Nanogold both unconjugated and conjugated, and shows you how to calculate your labeling exactly. Plus, select the right separation media from our extensive list of gels, and see a preview of some of the new products we are developing. This section will help you get the most out of Nanogold.
Guide to Gold Cluster Labeling: www.nanoprobes.com/LGuide.html
Spectra and labeling calculations: www.nanoprobes.com/LGuide4.html
To see our labeling reagents in motion, take a quick tour of our technology, complete with animated illustrations:
Technology Tour: www.nanoprobes.com/Label.html
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We have already shown how Nanogold® can be linked to DNA and to peptides; but covalent linking means that many other molecules that cannot be labeled with conventional colloidal gold can readily be labeled with Nanogold. Large or small, water-soluble or best handled in other solvents, all that is needed for successful gold-labeling is an accessible thiol (sulfhydryl) or amino- group. And with Monoamino-Nanogold, you can use many other heterobifunctional cross-linking reagents to link Nanogold to other functional groups.
Some examples:
You can also use charged Nanogold to label cellular or nuclear features with the opposite charge:
Charged Nanogold - general information: www.nanoprobes.com/LabRgts.html#charged
Charged Nanogold - references: www.nanoprobes.com/RefTopNG.html#Ncharged
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Undecagold is an 11-atom gold cluster, smaller than Nanogold but with the same covalent mode of activation and cross-linking. Although generally we recommend that you use Nanogold rather than undecagold for electron microscopy immunolabeling, undecagold has some useful applications as well use it for:
- STEM microscopy
- Diffraction studies
- Heavy atom derivatization of large proteins and membrane proteins in crystallography
- As a high-resolution microscopy size standard
General and catalog information and applications: www.nanoprobes.com/UndecaG.html
References sorted by application: www.nanoprobes.com/RefTopUG.html
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Gerhard Hacker and co-workers continue their work on in situ hybridization using Nanogold with autometallography as a detection system; see Graf, A. H., Cheung, A. L., Hauser-Kornberger, C., Dandachi, N., Tubbs, R. R., Dietze, O., and Hacker, G. W.; Appl. Immunohistochem. Molecul. Morphol., 8, 300-9 (2000).
Medline citation:
http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=11127922&dopt=Abstract
In related work, Van Noorden and co-workers found that signal amplification and Nanogold/silver enhancement was the only method sufficiently sensitive to properly demonstrate cathepsin B in the human colorectal mucosa. See Bleeker, F. E., Hazen, L. G., Kohler, A., and Van Noorden, C. J.; Acta Histochem., 102, 247-57 (2000), and Kohler, A., Lauritzen, B., and Van Noorden, C. J.; J. Histochem. Cytochem., 48, 933-41 (2000).
Medline citations:
http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=10990063&dopt=Abstract
http://www.ncbi.nlm.nih.gov:80/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=10858270&dopt=Abstract
Schwartz and Matouschek have used Nanogold and undecagold to determine the dimensions of the protein import channels in the outer and inner mitochondrial membranes; the larger Nanogold was excluded, while the smaller undecagold was able to pass through the channels (See: Schwartz, M. P., and Matouschek, A.: Proc. Natl. Acad. Sci. USA, 96, 13086-13090 (1999).
Abstract (html): http://www.pnas.org/cgi/content/abstract/96/23/13086
Full paper (PDF format): http://www.pnas.org/cgi/reprint/96/23/13086.pdf
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