A highly efficient charge-driven method to encapsulate bacteriophages in liposomes

Area of Science:

• Biotechnology
• Antimicrobial Therapy
• Nanotechnology

Background:

• Liposome-encapsulated bacteriophages show promise for treating multidrug-resistant infections by improving phage stability and targeted delivery.
• Existing encapsulation methods suffer from low efficiency (≤50%), phage inactivation, and poor scalability for industrial production.

Purpose of the Study:

• To develop and evaluate an electrostatically driven encapsulation method for producing phage liposomal formulations.
• To overcome the limitations of current methods by enhancing efficiency, scalability, and phage viability.

Main Methods:

• Utilized cationic lipids (DOTAP) and scalable micromixing systems (AXF™mini, confined impinging jet, microfluidic chip).
• Investigated various flow rate ratios and total flow rates to optimize encapsulation.
• Employed transmission electron microscopy, atomic force microscopy, and infrared spectroscopy for structural analysis.

Main Results:

• Achieved high encapsulation efficiency of 90-91% for both podovirus (PEV31) and myovirus (PEV1) using electrostatic interactions.
• Maintained phage viability with minimal reduction (<0.2 log10 titre).
• Produced uniformly sized liposomal phages (<1000 nm, PDI <0.3) with a slightly positive zeta potential.

Conclusions:

• The electrostatic encapsulation method effectively addresses key challenges in phage therapy, including efficiency and scalability.
• This versatile strategy accommodates diverse phage morphotypes while preserving viability.
• The developed liposomal phage formulations hold potential for industrial-scale antimicrobial applications.