• Future directions and requirements for tissue engineering biomaterials

      Arjunan, Arun; Baroutaji, Ahmad; Robinson, John; Praveen, Ayyappan S; Pollard, Andrew; Wang, Chang (Elsevier, 2021-02-24)
      A wide array of biomaterials are being developed to be used as tissue engineering scaffolds, including metals, ceramics, polymers, and composites. For all biomaterials, the challenge remains to achieve functionality to mimic the biomechanical environment, induce bioactivity, and support critical size tissue reintegration. This calls for a functional evolution in biomaterials to be used as tissue engineering constructs for partial and full tissue reconstruction. When characterizing biomaterials for tissue engineering, the relevant extensions include engineered surfaces, micro-patterns, and porous architectures along with, bioactive, bioresorbable, and infection resistant properties. Accordingly, functional biomaterials will drive the next generation of tissue engineering constructs. This paper, therefore, explores the major concepts, future direction, and recent signs of progress in the field of tissue engineering biomaterials. Traditional materials are not discounted entirely as bioinert materials are still relevant and emerging research offers new functionalities for them to support drug, gene, and cell tissue engineering. Therefore, an attempt is also made to explain how the requirements of biomaterials are changing to facilitate, sustain, control, and proliferate engineered tissue. The article begins with a brief introduction to the evolution of biomaterials followed by a commentary on their functional requirements when applied to tissue engineering. This is followed by an exploratory evaluation of key tissue engineering constructs and their qualifiers while systematically identifying their future direction and potential.
    • Future directions and requirements for tissue engineering biomaterials

      Arjunan, Arun; Baroutaji, Ahmad; Robinson, John; Praveen, Ayyappan S; Pollard, Andrew; Wang, Chang (Elsevier, 2021-02-24)
      A wide array of biomaterials are being developed to be used as tissue engineering scaffolds, including metals, ceramics, polymers, and composites. For all biomaterials, the challenge remains to achieve functionality to mimic the biomechanical environment, induce bioactivity, and support critical size tissue reintegration. This calls for a functional evolution in biomaterials to be used as tissue engineering constructs for partial and full tissue reconstruction. When characterizing biomaterials for tissue engineering, the relevant extensions include engineered surfaces, micro-patterns, and porous architectures along with, bioactive, bioresorbable, and infection resistant properties. Accordingly, functional biomaterials will drive the next generation of tissue engineering constructs. This paper, therefore, explores the major concepts, future direction, and recent signs of progress in the field of tissue engineering biomaterials. Traditional materials are not discounted entirely as bioinert materials are still relevant and emerging research offers new functionalities for them to support drug, gene, and cell tissue engineering. Therefore, an attempt is also made to explain how the requirements of biomaterials are changing to facilitate, sustain, control, and proliferate engineered tissue. The article begins with a brief introduction to the evolution of biomaterials followed by a commentary on their functional requirements when applied to tissue engineering. This is followed by an exploratory evaluation of key tissue engineering constructs and their qualifiers while systematically identifying their future direction and potential.
    • Metallic meta-biomaterial as biomedical implants

      Baroutaji, Ahmad; Arjunan, Arun; Robinsion, John; Ramadan, Mohamad; Abdelkareem, Mohammad A; Olabi, Abdul-Ghani (Elsevier, 2021-06-21)
      The demand for innovative biomaterials with adequate mechanical and biological properties that can be used to replace, repair, or regenerate bone tissues continues to increase rapidly due to the prevalence of osteoporosis, among the growing number of elderly people, which causes loss or weakening of bone. Over the past few years, meta-biomaterials have received increased attention for application in bone tissue regeneration and orthopedic implants due to their many desirable features such as adjustable permeability, big surface area, low weight, controlled micro-architecture, and customisable mechanical responses. Meta-biomaterials are artificially engineered porous structures where their mechanical performance is dominated by the architecture of their respective unit cells rather than the mechanical properties of the base material. Therefore, they can offer unique properties that are not readily available in natural materials.
    • Nanomaterials theory and applications

      Govindaraman, Loganathan T; Arjunan, Arun; Baroutaji, Ahmad; Robinson, John; Ramadan, Mohamad; Olabi, Abdul-Ghani (Elsevier, 2021-06-01)
      The behavior of matter at the nanoscale alters material properties in comparison to their bulk counterparts. Overall, materials at the nano-range demonstrate modified physical behaviors that offer favorable mechanical, thermodynamic, magnetic, optical, and biomedical properties for a range of applications. As such nanomaterials have their prominence in most scientific domains due to their ability to generate varied responses suitable for specific requirements. However, the implementation of nanomaterials in each situation requires a detailed understanding of the chemical and physical properties of the base materials, control parameters, and methods of fabrication. This paper introduces nanomaterials, their classification and measurement techniques followed by synthesis methods, common properties, applications, and prospects.
    • Smart tribological coating

      Arjunan, Arun; Baroutaji, Ahmad; Robinson, John; Olabi, Abdul-Ghani (Elsevier, 2021)
      Materials that can adapt their characteristics favorably to relevant external factors are defined as smart materials. The term “smart tribological coatings” defines a class of coatings that are capable of responding to their environment while offering an advantageous functionality while preserving their tribological property. The latest approach in coatings is to manipulate the material and structural composition of the deposition at submicron scales to develop functional architecture. This sequential fabrication of submicron layers featuring unique material compositions and topography result in unique and exotic properties suitable for the development of smart coatings. Several such smart coating architectures have been conceived and investigated by researchers that are summarized in this study. Notable examples of such coatings include sensing, self-healing, self-lubricating, self-cleaning, and bioactive systems. Surface architectures with enhanced and novel functionalities such as self-stratifying, super-insulating and thermochromic are also emerging and are likely to become part of the smart coating portfolio. This article starts by briefly introducing the primary concepts associated with smart tribological coatings along with their functionalities. The different types of coating structures and their smart characteristics are discussed in subsequent sections. Altogether, the article brings together the various concepts in smart tribological coatings that offer significant potential for a range of functional applications.
    • Tissue engineering concept

      Arjunan, Arun; Baroutaji, Ahmad; Robinson, John; Wang, Chang (Elsevier, 2021)
      Tissue engineering is a multidisciplinary methodology regarding the development of new tissue that can restore, maintain, or improve damaged tissues or whole organs. The conventional concept in tissue engineering features three distinct elements namely, cells, scaffolds, and bioactive factors, each having its characteristic role. Over the years, new concepts have evolved such as scaffold and cell-free architectures bringing new opportunities and challenges. The cell-free concept uses highly specialized biomaterials to create a bioresponsive scaffold that aids in vivo tissue regeneration. The scaffold-free concept, on the other hand, employs cell sheets, spheroids, or tissue strands as the fundamental building blocks replacing the conventional scaffold. The paper starts by introducing the primary elements associated with tissue engineering along with their functionalities. The various tissue engineering concepts are presented in subsequent sections and upcoming approaches such as bioprinting discussed. As such the paper brings together the various concepts in tissue engineering that offer significant potential for the generation of functional tissues and organs.