Multiparameter Quantific ation of Liposomes

A liposome is a tiny vesicle made from materials similar to a cell membrane. Drug-encapsulated liposomes have been considered the most clinically acceptable drug delivery systems. In this study, the Flow NanoAnalyzer was used to simultaneously detect the side-scatter (SS) and fluorescence (FL) signals generated by individual liposome particles at a speed of up to 10,000 nanoparticles/min. To address the size dependence of the refractive index of liposomes, different sizes of doxorubicin-loaded liposomes were fabricated and characterized to serve as calibration standards for measuring both particle size and drug content. This method provides a highly practical platform for the characterization of liposome vesicles.

Figure 1. Particle size and Dox content characterization of the DEL reference standards.

Figure 2. Multiparameter quantification of Dox-loaded liposome samples.

The superior sensitivity of the Flow NanoAnalyzer allows simultaneous detection of SS and FL signals of liposomes as small as 30 nm. Using DELs as a model, the application of the Flow NanoAnalyzer for the absolute quantification of particle size, drug content, fraction of drug encapsulation, and particle concentration of single liposomes is demonstrated.

ACS Appl. Mater. Interfaces, 2017, 9(16), 13913-13919.