Collagen is one of the most widely used biological materials in medical design. Collagen extracted from marine organisms can be a good biomaterial for tissue engineering applications due to its suitable properties. In this study, collagen is extracted from fish skin of Ctenopharyngodon Idella; then, the freeze drying method is used to design a porous scaffold. The scaffolds are modified with the chemical crosslinker N-(3-Dimethylaminopropyl)-N'-ethyl carbodiimide hydrochloride (EDC) to improve some of the overall properties. The extracted collagen samples are evaluated by various analyzes including cytotoxicity test, SDS-PAGE, FTIR, DSC, SEM, biodegradability and cell culture. The results of the SDS-PAGE study demonstrate well the protein patterns of the extracted collagen. The results show that cross-linking of collagen scaffold increases denaturation temperature and degradation time. The results of cytotoxicity show that the modified scaffolds have no toxicity. The cell adhesion study also shows that epithelial cells adhere well to the scaffold. Therefore, this method of chemical modification of collagen scaffold can improve the physical and biological properties. Overall, the modified collagen scaffold can be a promising candidate for tissue engineering applications.

Abstract
1. Introduction
2. Materials and Method
    2.1. Collagen extraction
    2.2. Sodium dodecyl sulphate polyacrylamide gelelectrophoresis (SDS-PAGE)
    2.3. Porous scaffold
    2.4. FTIR analysis
    2.5. DSC analysis
    2.6. Structural analysis
    2.7. Degradation test
    2.8. Cell study
    2.9. Statistical analysis
3. Results & Discussion
    3.1. SDS-PAGE analysis
    3.2. FTIR analysis
    3.3. DSC analysis
    3.4. Degradation results
    3.5. Cell study
4. Conclusion
Declaration of Interest Statement
References

• Esmaeil Biazar(Tissue Engineering Group, Department of Biomedical Engineering, Tonekabon Branch, Islamic Azad University, Tonekabon, Iran) Corresponding author
• Mahshad Kamalvand(Tissue Engineering Group, Department of Biomedical Engineering, Tonekabon Branch, Islamic Azad University, Tonekabon, Iran)
• Saeed Heidari Keshel(Department of Tissue Engineering and Applied Cell Sciences, School of Advanced Technologies in Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran)
• Bahareh Pourjabbar(Department of Tissue Engineering and Applied Cell Sciences, School of Advanced Technologies in Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran)
• Mustafa Rezaei-Tavirani(Proteomics Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran)