A Compensated Förster Resonance Energy Transfer-Based Platform for Quantitative Assessment of Liposome Integrity in...

Area of Science:

• Nanomedicine
• Biophysical Chemistry
• Pharmaceutical Sciences

Background:

• Liposomal carrier integrity is crucial for inhalable drug delivery efficacy.
• Current methods lack quantitative assessment of liposome stability throughout the inhalation process.
• Developing robust methods to monitor liposome structural integrity is essential for optimizing pulmonary drug delivery.

Purpose of the Study:

• To establish a compensated Förster resonance energy transfer (FRET)-based platform for quantitative assessment of liposome integrity during inhalation delivery.
• To enable accurate quantification of FRET signals from co-loaded liposomes (DiD/DiR) using spectrofluorometry and macroscopic imaging.
• To validate the platform's sensitivity and applicability in vitro and in vivo.

Main Methods:

• Co-loading liposomes with Förster resonance energy transfer (FRET) pairs (DiD donor/DiR acceptor).
• Compensating for donor fluorescence bleed-through and direct acceptor excitation for accurate FRET signal quantification.
• Utilizing spectrofluorometry, macroscopic imaging, Andersen cascade impactor for in vitro aerosol analysis, and in vivo mouse models for pulmonary residence studies.

Main Results:

• The compensated FRET/donor ratio effectively detected liposome disruption at lower Triton X-100 concentrations compared to membrane anisotropy.
• The FRET platform enabled simultaneous analysis of aerodynamic particle size distribution and stage-specific liposome integrity using an Andersen cascade impactor.
• In vivo studies demonstrated a time-dependent decline in liposome integrity within the lungs, correlating with pulmonary residence time.

Conclusions:

• The compensated FRET platform provides a sensitive and quantitative method to assess inhalable liposome integrity throughout the delivery process.
• This platform offers significant advantages for formulation development, stabilization strategies, and dosing regimen optimization for inhaled therapeutics.
• The FRET-based approach is adaptable to various cascade impactors and applicable to a broad range of nanocarriers, including vaccines and nucleic acid therapeutics.