Quantum Dot‐Based Nanotools for Bioimaging, Diagnostics, and Drug Delivery

Abstract

Quantum dots (QDs) are highly fluorescent nanocrystals with advanced photophysical and spectral properties: high brightness and stability against photobleaching accompanied by broad excitation and narrow emission spectra. Water-soluble QDs functionalized with biomolecules, such as proteins, peptides, antibodies, and drugs, are used for biomedical applications. The advantages of QD-based approaches to immuno-histochemical analysis, single-molecule tracking, and in vivo imaging (over traditional methods with organic dyes and fluorescent proteins) are explained. The unique spectral properties of QDs offer opportunities for designing systems for multiplexed analysis by multicolor imaging for the simultaneous detection of multiple targets. Conjugation of drug molecules with QDs or their incorporation into QD-based drug-delivery particles makes it possible to monitor real-time drug tracking and carry out image-guided therapy. Because of the tunability of their photophysical properties, QDs emitting in the near-infrared have become an attractive tool for deep-tissue mono- and multiphoton in vivo imaging. We review recent achievements in QD applications for bioimaging, targeting, and drug delivery, as well as challenges related to their toxicity and non-biodegradability. Key and perspectives for further development of advanced QD-based nanotools are addressed.

Engineering of Optically Encoded Microbeads with FRET‐Free Spatially Separated Quantum‐Dot Layers for Multiplexed Assays

“…[7][8][9] The unique optical properties make QDs ideal probes for multiplexed analysisa nd multicolor imaging as QDs of severalc olors may be excited simultaneously with as ingle light source, and their emission peaks can be distinguished with ah igh resolution. [10,11] Moreover,t he multiplexed flow cytometry analysis with QD-encoded microbeads does not require complicated compensation procedures thus increasing the sensitivity of analysis. [4] Since 2001, when the concept of multicolor optical coding of microbeads with QDs was first suggested, [12] an umber of approaches has been designedf or engineering QD-encoded microparticles:e mbedding of QDs into the microbeads during the microbeads manufacturing, [13] incorporation of QDs into pores of swollenmicroparticles, [12,14] doping of mesoporous microbeads with QDs, [15] the concentration-controlled flow-focusing approach, [16] layer-by-layer deposition technique, [17] and encapsulation of QDs into polyelectrolytem icrocapsules.…”

Quantitative and multiplexed detection for blood typing based on quantum dot–magnetic bead assay

“…17,18 These unique properties make QDs ideal probes compared with traditional fluorescent dyes and they have been widely used for DNA sequencing, protein molecular detection, and cell and tissue imaging. [19][20][21][22][23] QDs have also demonstrated great power in multiplexed analysis because they can be simultaneously excited without overlapping emission peaks. Previous studies demonstrated that these characteristics can offer convenience in the multiplex detection of biomolecules.…”

Quantum Dot Conjugates in Functional Imaging and Highly Sensitive Biochemical Assays

“…Semiconductor quantum dots (QDs) have emerged as alternative tools for cellular labelling, biochemical sensing, probing biocatalysed reactions, and drug delivery [4][5][6][7].…”