1.1. Introduction
Tissue engineering and regenerative medicine are fast developing approaches in the production of new organs and body tissues. On the other hand, it is a field that seeks to replace/repair or enhance the biological function of a tissue or an organ by manipulating cells via their extracellular environment [1â5].
The concept of directly engineering tissue was articulated in detail in 1985 [6]. The term âtissue engineeringâ was first used during a meeting sponsored by the National Science Foundation (NSF) in 1987. The first true tissue engineering symposium was held in 1988, where a working definition was proposed [4,5,7] in which tissue engineering was defined as âthe application of the principles and methods of engineering and life sciences toward the fundamental understanding of structureâfunction relationships in normal and pathological mammalian tissue and the development of biological substitutes to restore, maintain, or improve tissue functionâ [4,5,7]. Even though, everyone believe that the field of tissue engineering may be relatively new, the idea of replacing tissue with another goes as far back as the 16th century [8]. During 1546â99, Gasparo Tagliacozzi initiated a nose replacement that he had constructed.
Over the past few decades, there have been a wide range of research studies that have been conducted on the provision of tissue-engineered and regenerative medicine, which lead to a significant improvement in production of scaffolds with similar characteristics to a natural tissue/organ [4,5]. These scaffolds are needed, because of trauma/injury, genetic disorders, and diseases, which can lead to damage and degeneration of tissues in the human body, which necessitates treatments to facilitate their repair, replacement, or regeneration [8].
In reality, tissue engineering has a multidisciplinary approach consisting of cell engineering, molecular biology, biomaterial engineering, design, imaging, etc., to develop materials to replace/repair diseased or damaged tissue and restore and improve their function [9]. For instance, bone and joint diseases cause many people to suffer for years with crippling effects. With the progressive aging of the population, the need for functional tissue substitutes is increasing [10]. According to previous research studies, the cost of fractures in the United Kingdom is above ÂŁ5.1 billion each year [11]. Large bone defects resulting from trauma, tumors, infections, or congenital abnormalities often require reconstructive surgery to restore function [12,13]. Organ transplantation and mechanical devices have revolutionized medical practice but have limitations. New bone tissue engineering strategies have been proposed that promise greater bone restoration without many of the limitations of the current therapies [4,5,14]. Bone tissue engineering is a different method of treatment as compared with drug therapy, gene therapy, or permanent implants because engineered bone becomes incorporated within the patient, giving rise hopefully to a permanent cure for the patients suffering from various bone disorders. Bone cells (osteoblast, osteocyte, osteoclast), osteoconductive factor (three-dimensional matrices or scaffold), and osteoinductive factor (recombinant signaling molecules or growth factors) are the three main key elements (see Fig. 1.1) in the tissue engineering of bone [4,5,16]. This combination of cells, signals, and scaffold is often referred to as a tissue engineering triad [8].
Regenerative medicine for the past two decades has captured the attention of the scientific community mainly in the field of medicine that is expected to be used in near future instead of traditional therapies, which cause enormous side effects. Biomaterial scaffold is one of the main elements in this field, which work parallel to cells, environmental factors, and signaling molecules, which plays an important role in successful functional tissue engineering. Successful research studies were conducted for the past few years, and significant improvement and progress have been reported in reconstruction of various human tissues replacements and prosthesis including lung [17], kidney [18], bladder [19,20], intestine [21], bone [15,22], cartilage [19,20,23â26], skin [27,28], oral tissues [29...