title: Visualizing quantum dots in biological samples using silver staining.
abstract: Quantum dot (QD) based contrast agents are currently being developed as probes for bioimaging and as vehicles for drug delivery. The ability to detect QDs, regardless of fluorescence brightness, in cells, tissues, and organs is imperative to their development. Traditional methods used to visualize the distribution of QDs in biological samples mainly rely on fluorescence imaging, which does not account for optically degenerate QDs as a result of oxidative quenching within the biological environment. Here, we demonstrate the use of silver staining for directly visualizing the distribution of QDs within biological samples under bright field microscopy. This strategy involves silver deposition onto the surface of QDs upon reduction by hydroquinone, effectively amplifying the size of QDs until visible for detection. The method can be used to detect non-fluorescent QDs and is fast, simple, and inexpensive.
authors.affiliation: Institute of Biomaterials & Biomedical Engineering, Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Leo Y T
authors.initials: LY
authors.lastname: Chou
authors.forename: Hans C
authors.initials: HC
authors.lastname: Fischer
authors.forename: Steve D
authors.initials: SD
authors.lastname: Perrault
authors.forename: Warren C W
authors.initials: WC
authors.lastname: Chan
mesh_terms: D000818:Animals; D019187:Cadmium Compounds / Q000737:chemistry; D003287:Contrast Media / Q000032:analysis* / Q000493:pharmacokinetics; D006873:Hydroquinones; D008099:Liver / Q000737:chemistry; D008198:Lymph Nodes / Q000737:chemistry; D010084:Oxidation-Reduction; D045663:Quantum Dots; D051381:Rats; D019163:Reducing Agents; D018036:Selenium Compounds / Q000737:chemistry; D012680:Sensitivity and Specificity; D016622:Silver Staining / Q000379:methods*; D013440:Sulfides / Q000737:chemistry; D014018:Tissue Distribution; D017967:Zinc Compounds / Q000737:chemistry
chemical_list: D019187:Cadmium Compounds; D003287:Contrast Media; D006873:Hydroquinones; D019163:Reducing Agents; D018036:Selenium Compounds; D013440:Sulfides; D017967:Zinc Compounds; C058667:cadmium selenide; C031238:zinc sulfide; C031927:hydroquinone