Abstract

In the present study, the cell attachment/spreading behaviour of L929 mouse fibroblasts on chitosan membranes was evaluated by using physico-chemical properties. For this purpose chitosan membranes were prepared and then photochemically modified with the cell adhesive peptide RGDS (Arg-Gly-Asp-Ser). The physico-chemical properties of unmodified (CHI) and RGDS-modified chitosan (CHI-RGDS) membranes were evaluated by calculating surface free energy (γ_sv) and interfacial free energy (γ_sw) values using captive bubble contact angle measurements and harmonic mean equation. The cell attachment experiments were performed both in 10% FBS containing and serum-free media with CHI and CHI-RGDS membranes. Eventually, it was not possible to predict a direct relationship between the change in physico-chemical properties and L929 cell attachment behaviour. The experimental results obtained from cell attachment agree with the theoretical prediction for the free energy of adhesion except for the cell attachment on CHI membrane in serum-free medium. Although a negative interfacial free energy of adhesion was calculated for CHI membrane in serum-free medium (ΔF_adh = −2.19 ergs/cm²), the cell attachment was poor (70%) compared to CHI-RGDS (90%) and none of the cells were spread on CHI surface to gain a fibroblastic morphology. Negative energy of adhesion was calculated for CHI and CHI-RGDS in 10% FBS medium, in which 100% of cells were attached on the membranes correlating with the thermodynamic approach. It can be suggested that, adsorption of serum proteins strongly affected the cell attachment meanwhile the presence of biosignal RGDS molecules triggered the cell spreading in serum medium.

Keywords: Chitosan; RGDS; Contact angle; Surface free energy; Free energy of adhesion

Article Outline

1. Introduction

2. Materials and methods

2.1. Membrane preparation and biomodification

2.2. Surface characterization by SEM

2.3. Surface characterization by FTIR-ATR

2.4. Wettability by captive bubble method and surface free energy

2.5. Cell culture studies

2.5.1. Cell line and maintenance

2.5.2. Cell attachment

2.6. Other measurements

2.7. Statistical analysis

3. Results and discussion

3.1. Biomodification of chitosan membranes

3.2. FTIR-ATR analysis

3.3. Contact angle measurements and surface free energy calculations

3.4. Results of cellular attachment

3.5. Evaluation of cellular attachment by surface physico-chemical properties

3.6. Evaluation of cellular attachment by thermodynamic approach

4. Conclusion

Acknowledgements

References