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Fluorescence Recovery after Merging a Droplet to Measure the Two-dimensional Diffusion of a Phospholipid Monolayer
Published on: October 15, 2015
The structure of zwitterionic phosphocholine surfactant monolayers
M Yaseen1, J R Lu, J R P Webster
1Biological Physics Group, School of Physics and Astronomy, the University of Manchester, Sackville Street Building, Sackville Street, Manchester M60 1QD, UK.
Langmuir : the ACS Journal of Surfaces and Colloids
|June 14, 2006
Summary
Zwitterionic phosphocholine (PC) surfactants show strong water affinity and stable hydration, maintaining their structure even with temperature and salt changes. Their unique headgroup geometry influences chain immersion and surface biocompatibility.
Area of Science:
- Surface Chemistry
- Materials Science
- Biophysical Chemistry
Background:
- Phosphocholine (PC) surfactants are known for their biocompatibility.
- Understanding their interfacial structure is crucial for applications in biomaterials and drug delivery.
Purpose of the Study:
- To determine the structure of zwitterionic phosphocholine (PC) surfactant monolayers at the water surface.
- To investigate the hydration of PC headgroups and their behavior with changing temperature and salt concentration.
- To correlate PC surfactant structure with their surface properties and biocompatibility.
Main Methods:
- Neutron reflectivity measurements.
- H/D isotopic substitution for structural analysis.
- Kinematic approach for alkyl chain tilt angle determination.
Main Results:
- PC headgroup hydration is high and stable against temperature and salt variations.
- The fraction of the alkyl chain immersed in water (f(c)) is consistently low (~0.15) and independent of surface coverage.
- Increased alkyl chain length leads to increased tilt angle, while layer thickness remains constant.
- PC surfactants exhibit stronger headgroup hydration but lower chain immersion compared to nonionic and ionic surfactants.
Conclusions:
- The strong water affinity and structural order of PC headgroups contribute to their biocompatibility.
- PC headgroup geometry plays a key role in maintaining conformational order within the monolayer.
- The findings provide insights into the interfacial behavior of PC surfactants, relevant for designing biocompatible materials.
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