Dual signal-responsive liposomes for temperature-controlled cytoplasmic delivery

Area of Science:

• Biotechnology
• Materials Science
• Cell Biology

Background:

• Liposomes are crucial for drug delivery but often struggle with targeted intracellular release.
• Developing stimuli-responsive systems enhances control over drug release kinetics and location.

Purpose of the Study:

• To create novel liposomes responsive to both temperature and acidic pH for triggered destabilization.
• To evaluate the intracellular delivery efficiency of these dual signal-responsive liposomes.

Main Methods:

• Liposomes were functionalized with hyperbranched poly(glycidol) derivatives containing N-isopropylamide and carboxyl groups.
• HeLa cells were incubated with pyranine-loaded liposomes under different temperature and pH conditions.
• Intracellular delivery was assessed by observing the fluorescence pattern of pyranine using microscopy.

Main Results:

• At 28 °C, liposomes were endosomally trapped, showing punctate fluorescence.
• Upon heating to 45 °C in an acidic environment, liposomes destabilized, releasing pyranine into the cytosol (diffuse fluorescence).
• This dual-stimuli triggered release demonstrated efficient payload transfer into the cell cytoplasm.

Conclusions:

• Dual signal-responsive liposomes offer a promising platform for targeted intracellular delivery.
• The combination of temperature and acidic pH triggers efficient release of encapsulated molecules into the cytosol.
• These liposomes could be valuable for delivering membrane-impermeable therapeutics like siRNA and proteins.