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Controlling osteopontin orientation on surfaces to modulate endothelial cell adhesion
Lingyun Liu1, Shengfu Chen, Cecilia M Giachelli
1Department of Bioengineering, University of Washington, Seattle, WA 98195, USA.
Journal of Biomedical Materials Research. Part A
|May 28, 2005
Summary
Osteopontin (OPN) adsorption on surfaces depends on surface charge. Positively charged surfaces promote OPN orientation favorable for enhanced cell adhesion and spreading, crucial for biomaterial engineering.
Area of Science:
- Biomaterials Science
- Surface Chemistry
- Cell Biology
Background:
- Osteopontin (OPN) is an extracellular matrix protein involved in healing and inflammation.
- OPN's arginine-glycine-aspartic acid (RGD) motif mediates cell adhesion via integrins.
- Controlling OPN orientation on surfaces is key for biomaterial applications.
Purpose of the Study:
- Investigate OPN adsorption and cell adhesion on various surfaces.
- Determine how surface properties influence OPN conformation and presentation.
- Evaluate the impact of OPN orientation on endothelial cell interactions.
Main Methods:
- Utilized self-assembled monolayers (SAMs) with varied terminal groups (--CH3, --OH, --NH2, --COOH) on gold.
- Employed surface plasmon resonance (SPR) biosensors for protein adsorption analysis.
- Conducted atomic force microscopy (AFM) and in vitro cell adhesion assays.
Main Results:
- OPN adsorption was similar on --NH2 and --COOH surfaces, approaching monolayer coverage.
- Cell adhesion assays revealed significantly higher cell counts and spreading on --NH2 surfaces compared to --COOH.
- Surface coverage and cell spreading decreased in the order: --NH2 > Au > --CH3 > --COOH > --OH.
Conclusions:
- Surface charge critically influences OPN adsorption and conformation.
- Positively charged surfaces (--NH2) optimize OPN presentation for enhanced endothelial cell adhesion and spreading.
- Surface properties dictate OPN's bioactivity, impacting cell interactions for biomaterial design.