Quantum Dot-Loaded Liposomes to Evaluate the Behavior of Drug Carriers after Oral Administration

Abstract EN

We have developed submicron-sized liposomes modified with a mucoadhesive polymer to enhance peptide drug absorption after oral administration.

Liposomal behavior in the gastrointestinal tract is a critical factor for effective peptide drug delivery.

The purpose of this study was to prepare quantum dot- (QD-) loaded submicron-sized liposomes and examine liposomal behavior in the body after oral administration using in vivo fluorescence imaging.

Two types of CdSe/CdZnS QDs with different surface properties were used: hydrophobic (unmodified) QDs and hydrophilic QDs with glutathione (GSH) surface modifications.

QD- and GSH-QD-loaded liposomes were prepared by a thin film hydration method.

Transmission electron microscopy revealed that QDs were embedded in the liposomal lipid bilayer.

Conversely, GSH-QDs were present in the inner aqueous phase.

Some of the GSH-QDs were electrostatically associated with the lipid membrane of stearylamine-bearing cationic liposomes.

QD-loaded liposomes were detected in Caco-2 cells after exposure to the liposomes, and these liposomes were not toxic to the Caco-2 cells.

Furthermore, we evaluated the in vivo bioadhesion and intestinal penetration of orally administered QD-loaded liposomes by observing the intestinal segment using confocal laser scanning microscopy.