QDs versus Alexa: reality of promising tools for immunocytochemistry

Abstract

BackgroundThe unique photonic properties of the recently developed fluorescent semiconductor nanocrystals (QDs) have made them a potential tool in biological research. However, QDs are not yet a part of routine laboratory techniques. Double and triple immunocytochemistries were performed in HeLa cell cultures with commercial CdSe QDs conjugated to antibodies. The optical characteristics, due to which QDs can be used as immunolabels, were evaluated in terms of emission spectra, photostability and specificity.ResultsQDs were used as secondary and tertiary antibodies to detect β-tubulin (microtubule network), GM130 (Golgi complex) and EEA1 (endosomal system). The data obtained were compared to homologous Alexa Fluor 594 organic dyes. It was found that QDs are excellent fluorochromes with higher intensity, narrower bandwidth values and higher photostability than Alexa dyes in an immunocytochemical process. In terms of specificity, QDs showed high specificity against GM130 and EEA1 primary antibodies, but poor specificity against β-tubulin. Alexa dyes showed good specificity for all the targets tested.ConclusionThis study demonstrates the great potential of QDs, as they are shown to have superior properties to Alexa dyes. Although their specificity still needs to be improved in some cases, QDs conjugated to antibodies can be used instead of organic molecules in routine immunocytochemistry.

Evaluation of quantum dot conjugated antibodies for immunofluorescent labelling of cellular targets

“…Although Montón et al suggest that Qdot-Abs were more specific for proteins that are scarce in the cell [20], here we find that the specific labelling of proteins such as SC35 and talin could not be achieved with the with commercial Qdot-Abs.…”

Plasmonic Control of Radiative Properties of Semiconductor Quantum Dots Coupled to Plasmonic Ring Cavities

“…We employ colloidal semiconductor QDs (CdSe/ZnS) as target entities as they have many advantages over standard fluorescent dyes. In particular, QDs photobleach less and are brighter than most standard fluorescent dyes; [33][34][35][36] also, in contrast to strong and complicated structure-function relationships of organic dyes, modification of QDs surface chemistry can be achieved without large changes in their fluorescence behavior. [37][38][39] For these reasons, among others, they have been suggested as the active elements in many emitterbased systems.…”

Luminescent nanomaterials for droplet tracking in a microfluidic trapping array

“…Other droplet barcoding techniques utilizing organic dyes[18, 19] are also limited in their ability to simultaneously quantify different cellular outputs due to the spectral overlap of these dyes with common biochemical stains. [20–22] These issues have resulted in some limitations in the use of droplet microfluidics in multiplexed applications where simultaneous tracking of cellular outputs to different input conditions on a single platform is required.…”

“…[23–25] Because of their size-tuneable absorptions/emissions, and high fluorescence quantum yield, QDs are considered a better alternative to organic dyes. [21, 22] Although being widely used as fluorescent barcodes in platforms such as FACS[26, 27] and droplet microfluidics[28], there have been concerns regarding QDs’ cytotoxicity, with heavy metals being used in their crystal structure. [29] Rare earth (RE)-doped materials are a class of phosphors that have received attention for their potential applications in bio-imaging, sensing, and therapeutics.…”