**1. Introduction**

In this section, we made a short overview regarding classification of biocomposites, empha‐ sizing the motivation of using biomaterials derived from renewable resources and highlighting

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

the current challenges in natural‐derived biomaterials and their biomedical‐related applica‐ tions. We present relevant data regarding the properties of natural‐derived and renewable biomaterials.


**Table 1.** Classification of renewable biopolymers used for biocomposites fabrication.

Biocomposites are a combination of natural fibers (e.g., wood fibers: hard and soft wood) or nonwood fibers (e.g., rice straw, pineapple, sugar cane, jute, flax, banana, etc.) with polymer matrices from both of the renewable and nonrenewable resources [1]. **Table 1** includes a classification of biocomposite biomaterials based on renewable resources [2–5].

In recent years, researchers focused on environmentally friendly composite based on natural fibers [6]. Because of their advantages, recent developments in composite based on renewable resources lead to improved biomaterials biofabrication with enhanced support for global sustainability [7].

In particular case of medical applications, biocomposite based on renewable materials have ability to support cell adhesion, migration, proliferation and differentiation; therefore, they can induce extracellular matrix formation and promote tissue repair [8]. An overview of recent reviews, book chapters and articles published in the field of renewable biomaterials is given in **Table 2**.

Relevant data regarding the properties of natural renewable biomaterials with related results presented in this chapter are introduced.

Polysaccharide‐based biopolymers are of considerable interest as a source of renewable materials with applications in the biomedical, food, textile and energy industries [22].

Between them, chitin derivatives are widely studied [e.g., chitosan (CHT)]. Since chitosan is biocompatible and biodegradable, an ample diversity of interesting studies based on chitosan were reported [22].

Chitosan has been explored as a scaffold for tissue engineering due to its significant osteocon‐ ductivity, but minimal osteoinductive property [23, 24]. Chitosan has been prepared in various geometries such as thin films, scaffolds, sponges, fibers or other complex structures, for biomedical applications [25, 26].

the current challenges in natural‐derived biomaterials and their biomedical‐related applica‐ tions. We present relevant data regarding the properties of natural‐derived and renewable

> **Biocomposites/biofibers Natural biopolymers**

Biocomposites are a combination of natural fibers (e.g., wood fibers: hard and soft wood) or nonwood fibers (e.g., rice straw, pineapple, sugar cane, jute, flax, banana, etc.) with polymer matrices from both of the renewable and nonrenewable resources [1]. **Table 1** includes a

In recent years, researchers focused on environmentally friendly composite based on natural fibers [6]. Because of their advantages, recent developments in composite based on renewable resources lead to improved biomaterials biofabrication with enhanced support for global

In particular case of medical applications, biocomposite based on renewable materials have ability to support cell adhesion, migration, proliferation and differentiation; therefore, they can induce extracellular matrix formation and promote tissue repair [8]. An overview of recent reviews, book chapters and articles published in the field of renewable biomaterials is given

Relevant data regarding the properties of natural renewable biomaterials with related results

Polysaccharide‐based biopolymers are of considerable interest as a source of renewable

Between them, chitin derivatives are widely studied [e.g., chitosan (CHT)]. Since chitosan is biocompatible and biodegradable, an ample diversity of interesting studies based on chitosan

materials with applications in the biomedical, food, textile and energy industries [22].

classification of biocomposite biomaterials based on renewable resources [2–5].

Polysaccharides, chitin/ *chitosan*, glucose [3]

**Table 1.** Classification of renewable biopolymers used for biocomposites fabrication.

**Animal‐based fibers Wood‐based natural fibers Nonwood natural fibers**

and kenaf [4]

Cellulose, hemicellulose, and *lignin*, like flax, jute, sisal,

Straw fibers, bast, leaf, seed/fruit, grass fibers [5]

biomaterials.

[2]

Proteins, like wool, spider, and silkworm *silk fibroin*

108 Composites from Renewable and Sustainable Materials

sustainability [7].

were reported [22].

presented in this chapter are introduced.

in **Table 2**.

The chitosan incorporation in composite biomaterials enhances the mechanical property of the basic biomaterial. In Ref. [27], it was proved an increase in compressive strength by 33.07% and an enhancement of the proliferation of mouse preosteoblastic cells (MC3T3‐E1) upon addition of nano‐hydrohyapatite (nHA) to chitosan. Another example is given by Venkatesan et al. [28] which evidenced that the blending chitosan with an anionic polysaccharide alginate may stabilize the system by electrostatic interaction of them.


**Table 2.** Overview of recent reviews, book chapters and articles published in the field of renewable biomaterials.

Other studies have been dedicated to chitosan and its biocomposite scaffolds investigations under *in‐vivo* conditions. Ma et al. [29] demonstrated that chitosan/gelatin scaffolds degraded completely in 12 weeks, while promoted osteoblast proliferation *in‐vivo*.

As well as chitosan, lignin (Lig) is a renewable and a natural polymer [30]. This complex, amorphous organic polymer consists in a natural matrix which binds the strong and stiff cellulose units together, generally in natural wood. Lignin has been studied due to its antiox‐ idant and antimicrobial properties, making it the perfect candidate for biomedical applica‐ tions [31].

In the study of X. Pan et al. [32], lignin prepared from hybrid poplar wood chips exhibited higher antioxidant activities based on 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) assay. In the same time, in Ref. [33], it is reported that Kraft lignin from wood sources in pulp industry can protect the oxidation of corn oil, being as efficient as vitamin E.

Nada et al. [34] demonstrated the lignin antimicrobial activities toward some bacteria and fungi‐like Gram‐positive bacteria (Bacillus subtilis and Bacillus mycoids).

The lignin incorporation in composite biomaterials led to biofabrication of new compounds with enhanced bioactivity and osteoconductivity [35, 36]. An unaltered incorporation of lignin provides a composite with enhanced stability and improved interconnected structure, while increasing the coating cohesion, as showed in Refs [37, 38].

Renewable resources have therefore a functional role in providing easily available and often cheap biomaterials for biofabrication of new generation of implants.
