Oral delivery of near-infrared quantum dot loaded micelles for noninvasive biomedical imaging.

The purpose of this study is to design, develop, and characterize an optical imaging agent for oral administration. The hydrophobic, nanosized (7 nm), near-infrared (NIR) quantum dots (QDs) have been loaded into deoxycholic acid (DOCA) conjugated low molecular weight heparin (LMWH) micelles. The QD-loaded LMWH-DOCA (Q-LHD) nanoparticles have been characterized by electrophoretic light scattering (ELS) and a transmission electron microscope (TEM) which shows the average particle size was 130-220 nm in diameter. The Q-LHD nanoparticles also show the excellent stability in different pH conditions, and the release profile demonstrates the slow release of QDs after 5 days of oral administration. Concfocal laser microscopic scanning images show that the Q-LHD nanoparticles penetrate the cell membrane and are located inside the cell membrane. The real time pharmacokinetics studies show the absorption, distribution, metabolism, and elimination profile of Q-LHD nanoparticles, observed by the Kodak molecular imaging system (KMIS). This study has demonstrated that the orally administered Q-LHD nanoparticles are absorbed in the small intestine through the bile acid transporter and eliminated through the kidneys.