Ultrastructure of exogenous surfactants using cryogenic scanning electron microscopy

Area of Science:

• Biomaterials Science
• Pulmonary Medicine
• Microscopy

Background:

• Exogenous surfactants are crucial for treating Respiratory Distress Syndrome (RDS), reducing mortality rates.
• Commercial surfactants differ significantly in composition and biophysical properties.
• Understanding surfactant ultrastructure is key to developing improved treatments.

Purpose of the Study:

• To investigate and compare the liposomal formation and ultrastructure of three exogenous surfactants: Survanta, ALEC, and Exosurf Neonatal.
• To correlate ultrastructural findings with surfactant composition and potential function.

Main Methods:

• Cryogenic scanning electron microscopy was employed to visualize the ultrastructure of Survanta, ALEC, and Exosurf Neonatal.
• Detailed analysis of liposomal organization and membrane structures was performed.

Main Results:

• ALEC demonstrated the most pronounced and regular closed liposomal organization with an "onion-ring-like" internal bilayer structure.
• Survanta formed open membranous structures with wavy, ribbon-like membranes, potentially due to interactions with surfactant proteins.
• Exosurf Neonatal showed more obvious liposomal organization than Survanta but less than ALEC.

Conclusions:

• ALEC exhibits superior liposomal organization compared to Survanta and Exosurf Neonatal.
• The presence of proteins in Survanta may contribute to its unique membranous structures and potential for enhanced spreading.
• Further research into biomaterial ultrastructure could lead to improved artificial, protein-free surfactants with enhanced lung surface activity.