Optical Analysis of Beads Encoded with Quantum Dots Coated with a Cationic Polymer

Abstract

Quantum dots are incorporated onto small beads made of various materials thanks to the versatile layer‐by‐layer method. The high contrast, tri‐color gradient TEM image of a bead emphasizes quantum dots in red‐yellow spots. Below, quantum dot coated magnetic beads demonstrate bimodality with their bright fluorescence and alignment along field lines. An hyperspectral imaging inspired technique allowed faster statistical characterization of optically coded beads on a setup typical of biological experiments.

Hemoglobin‐CdTe‐CaCO3@Polyelectrolytes 3D Architecture: Fabrication, Characterization, and Application in Biosensing

“…While the problem of the first approach lies in the drawback of phase separation between the beads and QDs during the synthesis, the second method suffers from the drawback of a non-uniform distribution of QDs inside the beads. [15] The third method offers a facile and controllable means for the loading of QDs by using the layer-by-layer method. A uniform distribution of QDs was obtained when SiO 2 spheres were used as templates.…”

“…A uniform distribution of QDs was obtained when SiO 2 spheres were used as templates. [15] In another piece of work, biologically active polystyrene (PS) beads labeled with semiconductor quantum dots (QDs)with tailored QD loading were prepared via the layer-by-layer (LBL) assembly approach and applied in immunoassays. [13] However, the smooth surface and nonporous structure of the PS and the SiO 2 beads limited the loading of the QDs to a monolayer, [16] and an increase in the loading of the QDs could only be achieved by repetitive and tedious work of multilayer assembly.…”

Toward Automatic Label-Free Whispering Gallery Modes Biodetection with a Quantum Dot-Coated Microsphere Population

“…More details on these methods can be found elsewhere [17,33]. Briefly for the encapsulation, the cQDs were transferred from chloroform to water in presence of soluble poly(styrene-co-vinyl benzyl chloride) copolymer previously quaternized with N,N dimethylhexadecylamine.…”

Ultrasensitive simultaneous detection of four biomarkers based on hybridization chain reaction and biotin–streptavidin signal amplification strategy

“…To acquire independent signals for each biomarker in multianalytes sample, electrochemical researchers have validated different types of tags as nanowires (Walton et al, 2002;Tok et al, 2006), barcodes (Nicewarner-Peña et al, 2001;Sha et al, 2006;Stoeva et al, 2006;Pregibon et al, 2007), enzyme (Kojim et al, 2003;Wilson and Nie, 2006a;Wilson and Nie, 2006b;Fu et al, 2007), quantum dots (QD) (Han et al, 2001;Allen et al, 2007;Liu et al, 2007), dye-doped nanoparticles , metal ion (Hayes et al, 1994) and redox-probe (Song et al, 2010) etc. Redox probes could fast transmit electron, provide obvious redox peaks in electrochemical scan and have widely used in electrochemical sensors.…”