Fluorescence correlation spectroscopy of CdSe/ZnS quantum dot optical bioimaging probes with ultra-thin biocompatible coatings

• Published in: Optics communications Vol. 281; no. 7; pp. 1771 - 1780
• Main Authors: Murcia, Michael J., Shaw, David L., Long, Eric C., Naumann, Christoph A.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-04-2008
• Subjects: CdSe/ZnS quantum dots; FCS; FCS; CdSe/ZnS quantum dots
• ISSN: 0030-4018; 1873-0310
• DOI: 10.1016/j.optcom.2007.07.069

The colloidal stabilities and emission properties of CdSe/ZnS quantum dot (QD) optical probes capped with a variety of thin, hydrophilic surface coatings were studied using confocal fluorescence correlation spectroscopy. These coatings are based on mercaptoethanol, mercaptopropionic acid (with and without conjugated aminoethoxyethanol), lipopolymers (DSPE-PEG2000), cysteine (Cys), and a variety of Xaa-Cys dipeptides. The study shows that QDs with thin hydrophilic coatings can be designed that combine good colloidal stability and excellent emission properties (brightness). Furthermore, there is a general correlation between colloidal stability and brightness. The experiments reported illustrate that QDs with multiple types of thin coatings can be created for optical imaging applications in a biological environment while also maintaining a size below 10
nm.