Bioactive Materials in Medicine

Design and Applications

X. Zhao, J M Courtney, H Qian

• Publisher: Woodhead Publishing
• Year: 2011
• Print ISBN: 9781845696245
• eBook ISBN: 9780857092939
• Topic: Technology & Engineering
• Subtopic: Medical Technology & Supplies
• Index: Technology & Engineering

Bioactive materials play an increasingly important role in the biomaterials industry, and are used for a range of applications, including artificial organs, drug delivery systems, nanomedicine, and biosensors. Bioactive materials in medicine reviews the current status and ongoing development of bioactive materials for medical applications.Following an introduction to bioactive materials in medicine, part one covers the process of designing bioactive materials, including chapters on molecular design, nanotechnology, and tissue engineering. Part two focuses on the different applications of bioactive materials in medicine, with chapters discussing applications in orthopaedics, in the circulatory system, and as antibacterials. The final chapters focus on the uses of these materials in gene therapy, plastic surgery and body reconstruction, and in drug delivery systems.With its distinguished editors and international team of contributors, Bioactive materials in medicine is an essential reference for researchers and designers in industry, as well as those with an academic interest in the subject.- Discusses the current status and ongoing development of bioactive materials for medical applications- Explores the process of designing bioactive materials, including molecular design, nanotechnology, and tissue engineering- Assesses different applications of bioactive materials in medicine featuring applications in orthopaedics, in the circulatory system, and as antibacterials

1

Introduction to bioactive materials in medicine

X. Zhao, UK–China Research Academy of Bioactive Molecules and Materials (RABMM), UK

Abstract:

In this chapter, the comparison between bio-inert materials and bio-active materials is introduced, in order to understand the definition of bioactive materials. The current definition extends well beyond the original, and bioactive materials are now considered to be those materials which exhibit biological activities to stimulate the response of the biological system, when the materials are required to have clinical effects. The bioactive materials in this book range from traditional bioactive glass, bioactive ceramics in different forms for hard tissue repair to bioactive molecules–materials combination. In order to develop the clinical applications, assessment of the specific bioactivities is required. The principle of designing bioactive materials is required to take into account basic industrial safety and clinical efficacy. In addition, a bioactive material as the key element of a biomatrix in tissue engineering, utilised in conjunction with stem cells, offers future promise in regenerative medicine.

Key words

bioactive materials

tissue engineering

design of bioactive material

1.1 Definition of bioactive materials

Bioactive materials represent a new generation of biomaterials, which are different from the traditional bio-inert biomaterials. Traditionally, a

biomaterial is considered to be a non-viable material used in a medical device intended to interact with biological systems. Biomaterials may be distinguished from other materials in that they possess a combination of properties, including chemical, mechanical, physical, and biological properties that render them suitable for safe, effective and reliable use within a physiological environment [1].

However, by 1999, a biomaterial was defined as ‘a material intended to interface with biological systems to evaluate, treat, augment, or replace any tissue, organ, or function of the body’ [2]. This shows there is an increasing trend for a biomaterial to shift from a traditional bioinert material to a bioactive material.

Bioactive materials were originally discovered to react with the surrounding tissue to form a mechanically strong interfacial bond between a host tissue and an implant [3], with reference mainly to bone tissue repair and implant replacement. By definition, a bioactive material is ‘one that elicits a specific biological response at the interface of the material that results in the formation of a bond between the tissues and the material’ [4]. Nowadays, the term bioactive materials generally refers to biomaterials which have the capability to induce and conduct the response to the biological system upon interacting. They have the following bioactivities or functions to:

stimulate cell differentiation and proliferation;

stimulate gene and tissue regeneration;

release bioactive molecules to respond body actively and effectively for restoring and repairing the impaired functionality of the organs.

For example, an ideal bone graft material needs to have all the characteristics of osteoconductivity, osteogenicity and osteoinductivity. Osteoconductivity refers to the situation in which the bone graft substitute supports the attachment of new osteoblasts and osteoprogenitor cells, providing an interconnected structure through which new cells can migrate and new vessels can form. Osteogenicity refers to the situation when the osteoblasts that are at the site of new bone formation are able to produce minerals to calcify the collagen matrix that forms the substrate for new bone. Osteoinductivity refers to the ability of a bone graft to induce non-differentiated stem cells or osteoprogenitor cells to differentiate into osteoblasts [5,6]. To design a bioactive material to fulfil all these requirements is always a challenge when bone material is considered. Other than the application of bioactive materials in the traditional orthopaedics field, bioactive materials have become a most important part of biomedical engineering, and have been widely used in tissue engineering and artificial organs.

1.2 History of bioactive materials

The concept of a bioactive material was first suggested by Larry Hench in the late 1960s, when he found that certain glasses had the capability of bonding to living bone [3]. Since that time, more than ten groups around the world have shown that glasses containing SiO₂, CaO, P₂O₅, Na₂O and other smaller amounts of oxides in various compositions bond to bone [6–12].

The history of bioactive materials can be reviewed via the discovery and use of various bioactive materials, such as 45S5 BioGlass, bioactive glass-ceramics, such as Ceravital®, A/W glass-ceramics®, or machineable glass ceramics, further developed to dense hydroxyapatite (Hap), such as Durapatite® or Calcitite®; bioactive material composites, such as polyethylene (PE)–Hap composites, Palavital® and metal-fibre-reinforced bioglass, as shown in Table 1.1. It can be seen th...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Contributor contact details
• Foreword
• Chapter 1: Introduction to bioactive materials in medicine
• Part I: Designing bioactivematerials for use inmedicine
• Part II: Applications of bioactivematerials inmedicine
• Index