Core-shell silver nanoparticles for optical labeling of cells.

Analytical biochemistry (2014-04-24)
Kyle D Dukes, Kenneth A Christensen, George Chumanov
ABSTRACT

Silver nanoparticles have been modified with self-assembled monolayers of hydroxyl-terminated long chain thiols and encapsulated with a silica shell. The resulting core-shell nanoparticles were used as optical labels for cell analysis using flow cytometry and microscopy. The excitation of plasmon resonances in nanoparticles results in strong depolarized scattering of visible light, permitting detection at the single nanoparticle level. The nanoparticles were modified with neutravidin via epoxide-azide coupling chemistry, to which biotinylated antibodies targeting cell surface receptors were bound. The nanoparticle labels exhibited long-term stability in solutions with high salt concentrations without aggregation or silver etching. Labeled cells exhibited two orders of magnitude enhancement of the scattering intensity compared with unlabeled cells.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
2-Propanol, BioReagent, for molecular biology, ≥99.5%
Sigma-Aldrich
2-Propanol, suitable for HPLC, 99.9%
Sigma-Aldrich
2-Propanol, ACS reagent, ≥99.5%
Sigma-Aldrich
2-Propanol, anhydrous, 99.5%
Sigma-Aldrich
Ammonia solution, 7 N in methanol
Sigma-Aldrich
(3-Glycidyloxypropyl)trimethoxysilane, ≥98%
Sigma-Aldrich
Isopropyl alcohol, ≥99.7%, FCC, FG
Sigma-Aldrich
Isopropyl alcohol, meets USP testing specifications
Sigma-Aldrich
2-Propanol, puriss. p.a., ACS reagent, reag. ISO, reag. Ph. Eur., ≥99.8% (GC)
Sigma-Aldrich
Ammonia, anhydrous, ≥99.98%
Sigma-Aldrich
2-Propanol, HPLC Plus, for HPLC, GC, and residue analysis, 99.9%
Sigma-Aldrich
2-Propanol, BioUltra, for molecular biology, ≥99.5% (GC)
Sigma-Aldrich
Fluorescein, for fluorescence, free acid
Sigma-Aldrich
2-Propanol, puriss. p.a., ACS reagent, ≥99.8% (GC)
Sigma-Aldrich
2-Propanol, Laboratory Reagent, ≥99.5%
Supelco
2-Propanol, Pharmaceutical Secondary Standard; Certified Reference Material
Supelco
2-Propanol, analytical standard
Sigma-Aldrich
Tetramethyl orthosilicate, ≥99%
Sigma-Aldrich
2-Propanol, electronic grade, 99.999% trace metals basis
Sigma-Aldrich
2-Propanol, puriss., meets analytical specification of Ph. Eur., BP, USP, ≥99.5% (GC)
Sigma-Aldrich
Ammonia solution, 0.4 M in THF
Sigma-Aldrich
Tetramethyl orthosilicate, 98%
Sigma-Aldrich
Ammonia solution, 0.4 M in dioxane
Sigma-Aldrich
Ammonia solution, 2.0 M in methanol
Sigma-Aldrich
1-Undecanol, 99%
Sigma-Aldrich
Ammonia solution, 4 M in methanol
Sigma-Aldrich
Ammonia solution, 2.0 M in isopropanol
USP
2-Propanol, United States Pharmacopeia (USP) Reference Standard
Sigma-Aldrich
2-Propanol, suitable for HPLC, 99.5%
Sigma-Aldrich
Ammonia, puriss., anhydrous, ≥99.95%