ARTICLE Biomimetic mineralization of chitosan/gelatin cryogels and in vivo biocompatibility assessments for bone tissue engineering Fatma Öfkeli | Didem Demir | Nimet Bölgen Chemical Engineering Department, Mersin University, Mersin, Turkey Correspondence Nimet Bölgen, Chemical Engineering Department, Mersin University, Mersin, Turkey. Email: nimetbolgen@yahoo.com Funding information Mersin Üniversitesi, Grant/Award Number: 2016-2-TP2-1899 Abstract The objective of this study is to develop biomimetic chitosan: gelatin (CH:Gel) cryogels for bone tissue engineering, combining the biological recognition of natural polymers with the distinguished interconnected porosity of cryogels, and biomimicking properties of bone like hydroxyapatite. The control of the biomineralization process onto biomaterials should be evaluated before clini- cal application. Therefore, the effect of chitosan and gelatin ratios on the final properties of the cryogels were investigated. FTIR, XRD, and SEM analysis indicated that the SBF coating exhibited similar characteristics to hydroxyapa- tite. The cryogels showed good biocompatibility with L929 mouse fibroblasts. Clinical outcomes and gross pathological examination showed that neither necrosis nor foreign body reaction was noted at the end of implantation. The biomimetically mineralized scaffold was found to be non-irritant and non-toxic for bone tissue. The biological performance and favorable properties demon- strated that the SBF coated CH:Gel cryogel can be a promising biomimetic scaffold for bone tissue engineering applications. KEYWORDS biocompatibility, bioengineering, biomaterials, biomimetic 1 | INTRODUCTION Critical-size bone defects or bone loss as a result of inci- dents, such as, fractures, diseases (arthritis, osteoporosis, osteomyelitis, and osteosarcoma), surgeries (tumor exci- sion) or aging are one of the biggest unsolved challenges in bone regeneration. 1,2 The improving of bone defect treat- ment techniques begins with an understanding of the bio- logical, chemical, and physical properties of bone tissue. The chemical composition of bone consists of hydroxyapa- tite mineral (Ca 10 (PO 4 ) 6 (OH) 2 ), collagen, and water. 3 The interaction between all these components plays an active role in determining the mechanical behavior of bone. 4 Bone tissue engineering is a developing field that aims to create implantable bone substitutes for critical segmental and musculoskeletal defects. The main target is to direct tissue regeneration toward new bone forma- tion with the invasion and growth of surrounding cells by using a polymeric scaffold as a substituted material. 5 In other words, the scaffolds based on synthetic and natu- ral polymers or their composites act as an artificial extra- cellular matrix for osteoblasts (bone building cells) or stem cells that can become osteoblasts. 6 Furthermore, these materials play a critical role to create an appropri- ate environment for cell attachment, migration, prolifera- tion, long-term viability as well as filling bone defects while providing mechanical support during bone regen- eration or formation. 7 Naturally derived polymers have been used for scaf- fold fabrication have the potential superiority of Received: 22 June 2020 Revised: 31 October 2020 Accepted: 12 November 2020 DOI: 10.1002/app.50337 J Appl Polym Sci. 2020;e50337. wileyonlinelibrary.com/journal/app © 2020 Wiley Periodicals LLC 1 of 12 https://doi.org/10.1002/app.50337