7 - Biopolymer Composites in Field-Effect Transistors

Cellulose of bacterial origin, known as bacterial cellulose (BC), is one of the most versatile biomaterials that has a huge potential in tissue engineering due to its favourable mechanical properties, high hydrophilicity, crystallinity, and purity. Additional properties such as porous nano-fibrillar 3D structure and a high degree of polymerisation of BC mimic the properties of the native extracellular matrix (ECM), making it an excellent material for the fabrication of composite scaffolds suitable for cell growth and tissue development. Recently, the fabrication of BC-based scaffolds, including composites and blends with nanomaterials, and other biocompatible polymers has received particular attention owing to their desirable properties for tissue engineering. These have proven to be promising advanced materials in hard and soft tissue engineering. This review presents the latest state-of-the-art modified/functionalised BC-based composites and blends as advanced materials in tissue engineering. Their applicability as an ideal biomaterial in targeted tissue repair including bone, cartilage, vascular, skin, nerve, and cardiac tissue has been discussed. Additionally, this review briefly summarises the latest updates on the production strategies and characterisation of BC and its composites and blends. Finally, the challenges in the future development and the direction of future research are also discussed.

Graphene-based materials for tissue engineering

Surface modification of polymers by plasma treatments for the enhancement of biocompatibility and controlled drug release

In cardiovascular surgery, reconstruction and replacement of cardiac and vascular structures are routinely performed. Prosthetic or biological materials traditionally used for this purpose cannot be considered ideal substitutes as they have limited durability and no growth or regeneration potential. Tissue engineering aims to create materials having normal tissue function including capacity for growth and self-repair. These advanced materials can potentially overcome the shortcomings of conventionally used materials, and, if successfully passing all phases of product development, they might provide a better option for both the pediatric and adult patient population requiring cardiovascular interventions. This short review article overviews the most important cardiovascular pathologies where tissue engineered materials could be used, briefly summarizes the main directions of development of these materials, and discusses the hurdles in their clinical translation. At its beginnings in the 1980s, tissue engineering (TE) was defined as “an interdisciplinary field that applies the principles of engineering and the life sciences toward the development of biological substitutes that restore, maintain, or improve tissue function” (1). Currently, the utility of TE products and materials are being investigated in several fields of human medicine, ranging from orthopedics to cardiovascular surgery (2–5). In cardiovascular surgery, reconstruction and replacement of cardiac and vascular structures are routinely performed. Considering the shortcomings of traditionally used materials, the need for advanced materials that can “restore, maintain or improve tissue function” are evident. Tissue engineered substitutes, having growth and regenerative capacity, could fundamentally change the specialty (6). This article overviews the most important cardiovascular pathologies where TE materials could be used, briefly summarizes the main directions of development of TE materials along with their advantages and shortcomings, and discusses the hurdles in their clinical translation.

With the development of tissue engineering, the application of decellularized adipose matrix as scaffold material in tissue engineering has been intensively explored due to its wide source and excellent potential in tissue regeneration. Decellularized adipose matrix is a promising candidate for adipose tissue regeneration, while modification of decellularized adipose matrix scaffold can also allow it to transcend the limitations of adipose tissue source properties and applied to other tissue engineering fields, including cartilage and bone tissue engineering, neural tissue engineering, and skin tissue engineering. In this review, we summarized the development of the applications of decellularized adipose matrix in different tissue engineering and present future perspectives.Level of Evidence III This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Tissue engineering is a promising approach in replacing or improving tissues lost or has become nonviable due to disease or trauma by the use of scaffold materials by combining engineering and biochemical/physicochemical methods. Its purpose is to create suitable matrices that support cell differentiation and proliferation toward the formation of new and functional tissue.Marine-based natural compounds are potential scaffold feedstock material in tissue engineering owing to their biocompatibility and biodegradability while providing excellent biochemical/physicochemical properties. Numerous application areas and various fabrication routes techniques described in the literature attest to the importance of these materials in tissue regeneration. This review has been carried to merge the information from a large number of studies on the marine-based scaffold materials in tissue engineering into a coherent summary.KeywordsMarineBiomaterial(s)Tissue engineeringScaffold(s)

Hydrogels are useful materials as scaffolds for tissue engineering applications. Using hydrogels with additive manufacturing techniques has typically required the addition of techniques such as cross-linking or printing in sacrificial materials that negatively impact tissue growth to remedy inconsistencies in print fidelity. Thus, there is a need for bioinks that can directly print cell-laden constructs. In this study, agarose-based hydrogels commonly used for cartilage tissue engineering were compared to Pluronic, a hydrogel with established printing capabilities. Moreover, new material mixtures were developed for bioprinting by combining alginate and agarose. We compared mechanical and rheological properties, including yield stress, storage modulus, and shear thinning, as well as construct shape fidelity to assess their potential as a bioink for cell-based tissue engineering. The rheological properties and printability of agarose-alginate gels were statistically similar to those of Pluronic for all tests (p > 0.05). Alginate-agarose composites prepared with 5% w/v (3:2 agarose to alginate ratio) demonstrated excellent cell viability over a 28-day culture period (>∼70% cell survival at day 28) as well matrix production over the same period. Therefore, agarose-alginate mixtures showed the greatest potential as an effective bioink for additive manufacturing of biological materials for cartilage tissue engineering.

Fabrication and characterization of conductive chitosan/gelatin-based scaffolds for nerve tissue engineering

Articular cartilage defects and degeneration can be caused by multiple factors, and the current clinical treatment schemes for pathological changes are relatively limited. Engineered cartilage tissue represents an alternative therapy for repairing cartilage defects in regenerative medicine. The scaffold material is considered the framework of tissue engineering; thus, scaffold material selection plays a crucial role in the therapy outcome. Polycaprolactone (PCL)-hydroxyapatite (HA) has been applied as a scaffold material for bone and cartilage tissue engineering with nontoxic, harmless metabolites and proper physical properties. The extracellular matrix (ECM) is mainly composed of collagen and proteoglycan, as well as a large number of growth factors and cytokines, which provide a tissue-specific microenvironment for host cells. Adipose-derived stem cells are pluripotent stem cells, and transforming growth factor-β3 (TGF-β3) enables mesenchymal stem cells to promote ECM production. This study, via in vitro and in vivo experiments, elucidated that the synovium mesenchymal stem cells (SMSCs) + chondrocytes + ECM-PCL-HA repair system, which is constructed upon the ECM-PCL-HA scaffold material, exhibits an adequate chondrogenic ability and reparatory effect. Overall, ECM-PCL-HA can be defined as a biofunctional scaffold material. The SMSCs + chondrocytes + ECM-PCL-HA repair system showed good confluency between the new cartilage and the surface, as well as the interface of the adjacent host cartilage. Furthermore, the structure of new cartilage tissue is consistent with adjacency. Thus, it can be used as a preferred plan for articular cartilage defect repair. Impact statement Studies investigating the chondrogenic ability and reparatory effect of the synovium mesenchymal stem cells (SMSCs) + chondrocytes + extracellular matrix (ECM)-polycaprolactone (PCL)-hydroxyapatite (HA) repair system provided a theoretical and practical basis for choosing ECM-PCL-HA as the scaffold material for cartilage tissue engineering. In this study, the transforming growth factor-β3 (TGF-β3) gene was introduced into adipose-derived stem cells (ADSCs) using a lentiviral vector to enhance ECM production. The decellularized ADSCs-ECM-PCL-HA acted as a biofunctional scaffold material with suitable physicochemical properties, which was advantageous for SMSC and chondrocyte adhesion and growth. Lastly, the SMSCs + chondrocytes + ECM-PCL-HA repair system showed excellent capability in the flush fusion state of the prosthetic surface and interface.

With the development of tissue engineering and materials science, through the research of meniscus tissue engineering to discover novel tissue engineering materials, and further accelerate the research of meniscus tissue engineering, through clinical trials and application of finding appropriate meniscus substitute, which can provide a new mode of treatment for meniscus repair. The focus of the current study including the mechanism of meniscus injury can absorb the natural collagen meniscus tissue engineering scaffolds as feasibility analysis, stress stimulation, meniscus recovery mechanical factors in 4 aspects. Research shows that it has a good application prospect and wider space for meniscus tissue engineering repair of exercise-induced meniscus injury. But in practical application, the meniscus tissue engineering scaffold construction, research on extra cellular matrix composite and its tissue compatibility, repair after tissue engineering meniscus stress stimulation and can withstand the mechanical factors the problem is still the meniscus tissue engineering problems.

The aim of developing tissue engineering approaches are based on the principles of engineering and life sciences. Cells in multicellular tissues sense a set of complex biophysical and biochemical cues and integrate these inputs to greatly change their dynamic state. In this sense, the cell is itself a “smart material”. Thus, the key to the smart design of materials for tissue engineering is to consider the cell as a smart material. This chapter first explains the mechanism of cell material interactions with respect to how cells sense, integrate, transduce, and respond to factors inherent to the extracellular matrix (ECM). Second, the ECM determinants that affect tissue dynamics are listed with respect to space and time in the cell–ECM interaction. A phenomenological sense of space and time is important to design dynamic cues provided by the smart materials. Finally, these insights are organized into a design concept for smart materials in tissue engineering.

The extensive utilization of natural polymers in tissue engineering is attributed to their excellent biocompatibility, degradability, and resemblance to the natural extracellular matrix. These polymers have a wide range of applications such as delivering therapeutic medicine, detecting diseases, sensing biological substances, promoting tissue regeneration, and treating diseases. This is a brief review of current developments in the properties and uses of widely used biomedical polymers derived from nature. Additionally, it explores the correlation between the characteristics and functions of these materials in different biomedical applications and highlights the prospective direction for the advancement of natural polymer materials in tissue engineering.

Over the past thirty years, interest in how mammalian cells interact with materials has exploded, with applications ranging from diagnostic in vitro testing, to bioprocess engineering with microcarriers, and to tissue engineering. This interest has paralleled a revolution in material processing methods which allow scientists and engineers to create an enormous variety of micro- and nanotopological features. By studying aspects of cell behavior such as gene expression, viability, motility, and fate when cells are presented with simple architectural elements, biomedical engineers hope to build a toolbox of topological features that can be deployed to solve specific tissue engineering problems. In this chapter, we first discuss fundamental molecular biology-based mechanisms behind cell–material interactions and then focus specifically on mammalian cell interactions with nanofibers, nanofibrous microspheres, nanogrooves, nanopits, nanotubes, and nanopillars, along with their applications in tissue engineering.

Tissue engineering is simply defined as the replacement or regeneration of an injured or damaged cell through the fabrication of new tissue at any segment of the human body. It may be orthopaedic, cardiovascular, spinal, gastro, urological, dermal, etc. Generally, tissue-engineering materials are classified into two categories, synthetic and natural polymers. Due to some side effects caused by synthetic polymers, natural biopolymers are most preferable for use in a biological system. Biomaterial along with nanoparticles, drug incorporation of scaffold or hydrogel may speed up the tissue regenerative process. Bionanomaterials have ideal characteristics such as being biodegradable, biocompatible, nontoxic, useful in drug delivery, antimicrobial, antioxidant, etc. These properties of bionanomaterials improve or promote mechanical, biochemical, electrical properties and are also capable of differentiation, cell adhesion, proliferation and cultivating cell growth. This chapter introduces tissue engineering and biomaterials, then continues with a deeper discussion of bionanomaterial tissue engineering regeneration for cardiovascular, urological and dermal use.

Perspective insights into versatile hydrogels for stroke: From molecular mechanisms to functional applications