Frontiers in Biomaterials

Understanding cell-matrix interactions is crucial for the development of suitable three-dimensional (3D) scaffolds for tissue regeneration. Cell adhesion, migration, proliferation, differentiation, and signaling on two-dimensional (2D) planar substrates have been extensively studied for over three decades, generating considerable knowledge suggesting that cells can sense multiple features of the extracellular matrix (ECM), integrate that information, and respond to it. However, the cells in the body reside in and interact with a nano-structured 3D ECM network, and increasing evidence has shown that the cellular responses to the 3D environment are significantly different from those of 2D substrates. This chapter describes the current advances in controlling cellular responses to 3D scaffolds. The techniques of tailoring scaffolding chemical composition, architecture, and rigidity are highlighted from the biomaterials aspect, and their applications to regulating cell-scaffold interactions are illustrated.

Biodegradable materials have played a significant role in the construction of numerous types of scaffolds for tissue regeneration applications. Over the years several fabrication techniques have been developed for the preparation of three dimensional scaffolds with high affinities toward specific cell lines. This review chapter provides a succinct overview of some of the key aspects involved in engineering scaffolds that have been applied to three varied types of tissues- namely bone, skin and the myocardium. We have discussed some of the methods involved in the formation of highly fine-tuned biomaterials that can mimic natural tissues and encourage the regeneration of a desired tissue. It is expected that a combination of the appropriate scaffold material with ideal mechanical, electrical, and biological properties, along with biomedical imaging and computer generated datasets, will revolutionize the field of tissue engineering and bring us closer to the development of functional organs.

Nanocrystalline diamond films, which comprise the so called nanocrystalline diamond (NCD) and ultrananocrystalline diamond (UNCD), represent a class of biomaterials possessing outstanding mechanical, tribological, and electrical properties, which include high surface smoothness, high corrosion resistance, chemical inertness, superior electrochemical behavior, biocompatibility, and nontoxicity. These properties have positioned the nanocrystalline diamond films as an attractive class of materials for a range of therapeutic and diagnostic applications in the biomedical field. Consequently, the interaction of nanocrystalline diamond films with biomolecules and cells has been focus of intense research during the last years, with many studies focused in tailoring the properties of the films for the control of their biological performance. In this chapter, the current knowledge regarding the biological performance of nanocrystalline diamond films is reviewed from an application-specific perspective, covering topics such as enhancement of cellular adhesion, anti-fouling coatings, non-thrombogenic surfaces, micropatterning of cells and proteins, and immobilization of biomolecules for bioassays. In order to better understand the terminology used in the literature, which is related to the fabrication and surface functionalization of this class of materials, some of the most common approaches for synthesis and modification of CVD diamond films is introduced. Although many challenges still remain, it is envisioned that the application of this unique class of materials will significantly influence the next generation of biomedical devices.

This chapter discusses in detail the design and synthetic strategies of ceramics for biomedical application, the biocompatibility as well as new emerging trends towards the application of ceramic materials in the biomedical field. Ceramics are a promising group of materials having potential applications in various fields such as engineering, technology, medicine etc. They are inorganic materials and can be prepared by high temperature as well as low temperature processes. The porosity, crystallinity, composition etc. are the features which determine the property of ceramics. These characteristics were tuned to get a desired property at the molecular level for the intended application by appropriate modification in the synthesis process of ceramics as well as functionalization with other materials. They could be designed from bulk materials to nano level materials. They usually fall in the category of bioinert, bioactive as well as resorbable ceramics. Based on their activity they find application in biomedical field. In the biomedical field ceramic materials were used as substitute materials for bone and teeth as well as coatings for metallic implants. Advanced research is going on in the molecular level modification of ceramic materials for developing artificial transplantation materials, drug release materials as well as materials for tissue engineering and gene therapy applications.

Dental tissue injuries significantly affect the quality of life of hundreds of people worldwide. Although dental implants can be functionally effective in many cases, they are not able to completely satisfy all the aspects of regenerative dentistry. Tissue engineering using innovative biomaterial scaffolds that support cells for functional regenerative dental tissues offers new possibilities for clinical dentistry. There have been several attempts to examine different biomaterial scaffolds and cell sources to regenerate substitutes for natural extracellular matrix analogs. It is believed that regenerative dentistry involving scaffolds, stem cells, and growth factors will become common within the next twenty years. This chapter compiles a thorough review on the current developments and challenges in scaffolding techniques that are of particular significance for regenerative dentistry.

Polyesters represent a class of polymers comprised of backbone ester linkages offering opportunities to tune the macromolecular properties according to the needs of specific applications. The polyesters developed to date have generated an enormous interest because of their applicability in the biomedical field. Although these are flexible materials in the sense that they can be chemically tuned to obtain the desired properties, one of the important parameters that has to be considered when designing the material for biomedical applications represents the biocompatibility.

The present book chapter aims to review the recent advances for the most commonly studied polyester biomaterials. The first section of this chapter will focus on the synthesis strategies of polyesters as well as possible modification strategies. The second section of this chapter will highlight several polymer processing methods used to obtain scaffolds with different architectures for tissue engineering applications.

Bioresorbable polymers represent a valuable choice for the fabrication of innovative scaffolds for tissue engineering applications. However, their actual ability to support the regenerative process needs to be carefully assessed. The extracellular matrix (ECM) is a complex functional structure providing specific cues and it should be replicated to promote an effective tissue regeneration after implantation. In this regard, electrospinning is a straightforward technique for the production of ECM-like scaffolds. Natural polymers might be promising candidates due to cellular affinity, even if affected by fast degradation and low mechanical stability. This limitation can be overcome by means of a cross-linking process, giving a hydrogel-like behavior to the final structure that can be usefully considered for the long-term release of drugs and growth factors.

This chapter is aimed firstly to review the potential of cross-linked electrospun natural polymers. Experimental results of the evaluation of cross-linked electrospun gelatin scaffolds, as suitable substrates to be loaded with vascular endothelial growth factor, are also herein presented.

Wound healing and its medical complications present a huge burden to health care worldwide. Current tissue engineering materials are far from satisfactory in meeting desirable safety and efficacy. Due to the intricate three-dimensional nanostructure, flexibility in shape design and multifunctional surface modification, advanced nanomaterials offer new hopes for revolutionising modern medicine. The potential of their applications in medical research and clinical practice include diagnosis, treatment, imaging and tissue regeneration. This chapter reviews the progress made in the application of nanomaterials in skin tissue engineering in the last decade. It mainly focuses on materials of biological origins that are biodegradable, non-toxic, and biocompatible with cells at target sites. The characteristics of novel biofunctional scaffolds, safety and future trend of nanomaterial application in tissue engineering are also discussed, aiming to promote continuous research effort in developing scaffold materials for optimisation of skin regeneration.

Incorporation of bioactive component around the surface of synthetic polymeric fiber is essential to improve the biocompatibility of scaffold. Core-shell structured nylon-6/lactic acid (LA) nanofibers have been produced via single-spinneret electrospinning from the simple blending of LA and nylon-6 solution. The low evaporation rate and plasticizer property of LA was found to be responsible for the formation of point-bonded morphology whereas solvent degradation of nylon-6 with complex phase separation mechanism could give spider-web-like architecture of the mat and core-shell structure of the composite fibers. These fibers were further treated with calcium base to convert surface LA into calcium lactate (CL) which could increase the biocompatibility of composite mat. The SBF incubation test and in vitro cell compatibility test showed that CL/nylon-6 composite mat has far better biocompatibility compared to the pristine nylon-6 scaffold. Therefore, the novel nanofibrous composite mat may become a potential candidate for bone tissue engineering.

Several types of nanoparticles are being evaluated for therapeutic and diagnostic applications. Although the biocompatibility of these nanoformulations has been evaluated in different models, it is of utmost importance to standardize the tests in order to advance our knowledge in this area. This book chapter summarizes experimental results related to the in vitro and in vivo toxicity of three types of nanoparticles: gold, silica and poly(lactic-co-glycolic acid). The chapter gives an overview about the methodologies that can be used to evaluate the toxicity of the nanoparticles. Whenever possible, a correlation between NP size, chemical composition, charge and concentration with toxicity is given. We further discuss the main mechanisms of nanomaterials toxicity including cell membrane perturbation, oxidation stress, and inflammatory response.

Considerable endeavors have been devoted to the synthesis of biocompatible scaffolds with tunable new structures and improved bioactivities. Within the field of bioceramics, silica-based ordered porous materials are receiving increasing attention by the biomaterials scientific community because silica is the main constituent of many biocompatible porous scaffold materials. In addition, dietary silicon plays an important role in bone formation and is markedly present in active calcification sites, stimulating the expression of genes involved in bone and cartilage formation and concurrently, inducing osteogenic differentiation and cell mineralization. More importantly, silicabased scaffolds hold their capability to host different guest molecules, representing a new generation of structurally unique materials. This chapter collects and discusses the current advances in silica-based scaffolds. The synthetic methods of tailoring scaffolding chemical composition and architecture are highlighted.