title: Minimizing nonspecific cellular binding of quantum dots with hydroxyl-derivatized surface coatings.
abstract: Quantum-dot (QD) nanocrystals are promising fluorescent probes for multiplexed staining assays in biological applications. However, nonspecific QD binding to cellular membranes and proteins remains a limiting factor in detection sensitivity and specificity. Here we report a new class of hydroxyl (-OH)-coated QDs for minimizing nonspecific cellular binding and for overcoming the bulky size problems encountered with previous surface coatings. The hydroxylated QDs are prepared from carboxylated (-COOH) dots via a hydroxylation and cross-linking process. With a compact hydrodynamic size of 13-14 nm (diameter), they are highly fluorescent (>60% quantum yields) and stable under both basic and acidic conditions. By using human cancer cells, we have evaluated their superior nonspecific binding properties against that of carboxylated, protein-coated, and poly(ethylene glycol) (PEG)-coated QDs. Quantitative cellular staining data indicate that the hydroxylated QDs result in a dramatic 140-fold reduction in nonspecific binding relative to that of carboxylated dots and a still significant 10-20-fold reduction relative to that of PEG- and protein-coated dots.
authors.affiliation: Department of Biomedical Engineering, Emory University, 101 Woodruff Circle, Suite 2001, Atlanta, Georgia 30322, USA.
authors.forename: Brad A
authors.initials: BA
authors.lastname: Kairdolf
authors.forename: Michael C
authors.initials: MC
authors.lastname: Mancini
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Smith
authors.forename: Shuming
authors.initials: S
authors.lastname: Nie
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D000588:Amines / Q000737:chemistry; D019187:Cadmium Compounds / Q000737:chemistry; D005456:Fluorescent Dyes / Q000737:chemistry*; D006367:HeLa Cells; D006801:Humans; D006900:Hydroxylation; D008856:Microscopy, Fluorescence; D053758:Nanoparticles / Q000737:chemistry*; D045663:Quantum Dots; D018036:Selenium Compounds / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet; D013440:Sulfides / Q000737:chemistry; D013499:Surface Properties; D017967:Zinc Compounds / Q000737:chemistry
chemical_list: D000180:Acrylic Resins; D000588:Amines; D019187:Cadmium Compounds; D005456:Fluorescent Dyes; D018036:Selenium Compounds; D013440:Sulfides; D017967:Zinc Compounds; C034939:cadmium sulfide; C006903:carbopol 940; C058667:cadmium selenide; C031238:zinc sulfide; C008699:octylamine