Bactericidal Activity of Lipid-Shelled Nitric Oxide-Loaded Microbubbles

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Infectious Diseases

Background:

• Antibiotic resistance is a growing global health crisis, necessitating novel therapeutic strategies.
• Nitric oxide (NO) possesses potent bactericidal and anti-biofilm properties, but its therapeutic application is limited by its instability.
• Microbubbles (MB) offer a potential platform for controlled delivery of therapeutic agents like NO.

Purpose of the Study:

• To characterize nitric oxide-loaded microbubbles (NO-MB) stabilized with a lipid shell.
• To evaluate the feasibility of using these NO-MB for *in vitro* antibacterial therapy.
• To assess the impact of co-encapsulating NO with octafluoropropane (OFP) on MB properties and efficacy.

Main Methods:

• NO-MB and NO-OFP-MB were prepared and characterized for size distribution and acoustic attenuation.
• Ultrasound was used to trigger gas payload release, and NO concentration was measured using an amperometric sensor.
• The bactericidal efficacy against *Staphylococcus aureus* (SA) USA 300 was assessed *in vitro*.

Main Results:

• Co-encapsulation of NO with OFP increased MB volume and acoustic attenuation.
• Ultrasound successfully triggered gas release from NO-OFP-MB, delivering higher NO concentrations than saturated solutions.
• NO-OFP-MB demonstrated enhanced bactericidal efficacy against *S. aureus* compared to control groups.

Conclusions:

• Encapsulating NO with OFP in lipid-shelled MB improves NO payload delivery and enhances antibacterial efficacy.
• NO-OFP-MB show feasibility for antibacterial applications, with potential for treating resistant infections.
• Further studies are needed to explore the limitations and optimize NO-OFP-MB for clinical translation.