title: Single particle quantum dot imaging achieves ultrasensitive detection capabilities for Western immunoblot analysis.
abstract: Substantially improved detection methods are needed to detect fractionated protein samples present at trace concentrations in complex, heterogeneous tissue and biofluid samples. Here we describe a modification of traditional Western immunoblotting using a technique to count quantum-dot-tagged proteins on optically transparent PVDF membranes. Counts of quantum-dot-tagged proteins on immunoblots achieved optimal detection sensitivity of 0.2 pg and a sample size of 100 cells. This translates to a 10(3)-fold improvement in detection sensitivity and a 10(2)-fold reduction in required cell sample, compared to traditional Westerns processed using the same membrane immunoblots. Quantum dot fluorescent blinking analysis showed that detection of single QD-tagged proteins is possible and that detected points of fluorescence consist of one or a few (<9) QDs. The application of single nanoparticle detection capabilities to Western blotting technologies may provide a new solution to a broad range of applications currently limited by insufficient detection sensitivity and/or sample availability.
authors.affiliation: Department of Biomedical Engineering,Oregon Health and Science University, Portland, OR 97239, USA.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Scholl
authors.forename: Hong Yan
authors.initials: HY
authors.lastname: Liu
authors.forename: Brian R
authors.initials: BR
authors.lastname: Long
authors.forename: Owen J T
authors.initials: OJ
authors.lastname: McCarty
authors.forename: Thomas
authors.initials: T
authors.lastname: O'Hare
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Druker
authors.forename: Tania Q
authors.initials: TQ
authors.lastname: Vu
mesh_terms: D015153:Blotting, Western / Q000592:standards*; D045663:Quantum Dots; D012680:Sensitivity and Specificity