Semiconductor Quantum Dots for Biosensing and In Vivo Imaging

Dept. of Radiol., Stanford Univ., Stanford, CA
IEEE Transactions on NanoBioscience (Impact Factor: 2.31). 04/2009; 8(1):4 - 12. DOI: 10.1109/TNB.2009.2017321
Source: IEEE Xplore


Semiconductor quantum dots (QDs) have captivated researchers in the biomedical field over the last decade. Compared to organic dyes and fluorescent proteins, QDs have unique optical properties such as tunable emission spectra, improved brightness, superior photostability, and simultaneous excitation of multiple fluorescence colors. Since the first successful reports on the biological use of QDs a decade ago, QDs and their bioconjugates have been successfully applied to various imaging applications including fixed cell labeling, live-cell imaging, in situ tissue profiling, fluorescence detection and sensing, and in vivo animal imaging. In this review, we will briefly survey the optical properties of QDs, the biofunctionalization strategies, and focus on their biosensing and in vivo imaging applications. We conclude with a discussion on the issues and perspectives on QDs as biosensing probes and in vivo imaging agents.

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    • "While nearly all carboxy-terminated ligands limit QDs dispersion to basic pH, silica shell encapsulation provides stability over much broader pH range. The third method maintains native ligands on the QDs and uses variants of amphiphilic diblock and triblock copolymers and phospholipids to tightly interleave the alkylphosphine ligands through hydrophobic interactions (Michalet et al. 2005; Xing et al. 2009). Aside from rendering water solubility, these surface ligands play a critical role in insulating, passivating and protecting the QD surface from deterioration in biological media (Cai et al. 2007). "
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