Revealing the Structural Intricacies of Biomembrane-Interfaced Emulsions with Small- and Ultra-Small-Angle Neutron...

Area of Science:

• Colloid and Surface Science
• Biomaterials Engineering
• Neutron Scattering Physics

Background:

• Cell membranes enhance colloidal stability and biological properties for biomedical applications.
• The internal structure of emulsions interfaced with red blood cell (RBC) and platelet (PLT) membranes is not well understood.
• Advanced characterization techniques are needed to elucidate complex biointerfaced colloidal structures.

Purpose of the Study:

• To systematically investigate the structure of perfluorohexane (PFH) emulsions stabilized by RBC and PLT membranes using small- and ultra-small-angle neutron scattering (SANS and USANS).
• To determine the structural characteristics of these biointerfaced emulsions and compare them with other imaging techniques.
• To highlight the utility of SANS/USANS in characterizing novel bio-colloids for biomedical applications.

Main Methods:

• Utilized SANS and USANS with contrast variation to probe RBC/PFH and PLT/PFH emulsions.
• Employed a deuterium oxide solvent matching the scattering length density of cell membranes (1.5 × 10^-6 Å^-2).
• Applied polydispersed sphere models and invariant analysis to determine droplet size and core structure.

Main Results:

• Determined the scattering length density of RBC and PLT membranes to be 1.5 × 10^-6 Å^-2.
• Estimated droplet diameters of 770 nm for RBC/PFH and 1.5 µm for PLT/PFH emulsions.
• Revealed entirely liquid perfluorohexane cores, contrasting with electron microscopy observations of bubble-droplet systems, demonstrating the power of neutron scattering.

Conclusions:

• SANS and USANS are critical tools for characterizing the true structure of biointerfaced colloids.
• The study uncovered native liquid perfluorohexane core structures within RBC/PFH and PLT/PFH emulsions.
• These findings offer insights into novel colloidal structures with significant potential for biomedical applications and clinical translation.