Tissues Regeneration

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**Chapter 4**

**Abstract**

Chitosan Based Biocomposites for

Bone is the second most transplanted organ, just after blood. It provides structural support, protection for organs and soft tissues. It holds some critical biological processes such as the bone marrow blood forming system. It is responsible for storing and supplying minerals such calcium and phosphate. Bone is a connective tissue formed by two predominant phases: an inorganic phase containing mainly apatitic calcium and phosphate and an organic phase made of fibrous type I collagen. This natural biocomposite has many biological features such osteoconductivity, osteoinductivity, osteogenicity and is subject to a continuous remodeling process through osteoclastic and osteoblastic activities. In biomedical engineering, the restoration of damaged hard tissue with autologous bone is not always possible or even the best option. The development of some safe and low-cost alternatives such as biocomposites that mimic organic and calcified bone materials have shown very good results and offer an alternative to autologous bone implants. However, the mechanical properties of biocomposites still present a big challenge as a hard tissue substitute. This chapter reviews the properties of bone substitute materials chitosan and calcium phosphates, discusses strategies used in the treatment of calcified hard tissues as well as new

**Keywords:** Bone, Chitosan, Calcium phosphate, Bioceramics, Biocomposites

Bone is the second most transplanted tissue in the world, second only to blood [1]. Hundreds of millions of people worldwide are affected by musculoskeletal conditions which are on the increase with aging population and lifestyle. Bone is a critical tissue within the vertebrates. It is a dynamic organ with many functions. It provides load bearing, body structural support onto which musculature is attached, protection for vital organs and soft tissues (brain, heart, lung, etc), and enables locomotion and motor functions. It is the host of important biological processes critical cells such as postnatal stem cell populations that support hematopoiesis, myelopoiesis, and skeletogenesis. Bone is also responsible for storing and supplying of minerals such as calcium and phosphate [2]. Native bone is a connective tissue made of two predominant components: a mineralized and an unmineralized phase. The mineralized inorganic phase contains mainly crystalline apatitic calcium phosphate (70%), water (20%), and the non-mineralized organic phase (10%) is made of fibrous type I collagen, proteins, polysaccharides and lipids (**Figure 1**) [3].

Hard Tissue Engineering

*Fouad Dabbarh, Noureddin Elbakali-Kassimi* 

*and Mohammed Berrada*

approaches developed in this field.

**1. Introduction**
