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Abstract

This chapter explains the importance of 3D cell culture and highlights its potential and benefits in comparison to traditional 2D cultivation. Since 3D cell culture is supposed to mimic the in vivo situation, we will also have a close look on the complex composition of the in vivo microenvironment and why 2D cultivation does not resemble the in vivo situation. Furthermore, we will cover the most important approaches for 3D cell culture which are matrix-free and matrix-based cultivation as well as bioprinting. Also, the main applications of 3D cell culture, in vitro tissue or disease models and tissue engineered constructs for tissue repair or regeneration, will be introduced. Finally, you will learn that 3D cell culture has its limitations and challenges when it comes to the analysis and monitoring of 3D cell culture processes.

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This is a thoroughly revised, updated, and expanded edition of a classic illustrated introduction to the structural materials in natural organisms and what we can learn from them to improve man-made technolog---from nanotechnology to textiles to architecture. Julian Vincent's book has long been recognized as a standard work on the engineering design of biomaterials and is used by undergraduates, graduates, researchers, and professionals studying biology, zoology, engineering, and biologically inspired design. This third edition incorporates new developments in the field, the most important of which have been at the molecular level. All of the illustrations have been redrawn, the references have been updated, and a new chapter on biomimetic design has been added. Vincent emphasizes the mechanical properties of structural biomaterials, their contribution to the lives of organisms, and how these materials differ from man-made ones. He shows how the properties of biomaterials are derived from their chemistry and interactions, and how to measure them. Starting with proteins and polysaccharides, he shows how skin and hair function, how materials self-assemble, and how ceramics such as bone and mother-of-pearl can be so stiff and tough, despite being made in water in benign ambient conditions. Finally, he combines these topics with an analysis of how the design of biomaterials can be adapted in technology, and presents a series of guidelines for designers. An accessible illustrated introduction with minimal technical jargon Suitable for undergraduates and more advanced readers Integrates chemistry, mechanics, and biology Includes descriptions of all biological materials Presents simple exposition of mechanical analysis of materials.
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Elastin is a key extracellular matrix protein that is critical to the elasticity and resilience of many vertebrate tissues including large arteries, lung, ligament, tendon, skin, and elastic cartilage. Tropoelastin associates with multiple tropoelastin molecules during the major phase of elastogenesis through coacervation, where this process is directed by the precise patterning of mostly alternating hydrophobic and hydrophilic sequences that dictate intermolecular alignment. Massively crosslinked arrays of tropoelastin (typically in association with microfibrils) contribute to tissue structural integrity and biomechanics through persistent flexibility, allowing for repeated stretch and relaxation cycles that critically depend on hydrated environments. Elastin sequences interact with multiple proteins found in or colocalized with microfibrils, and bind to elastogenic cell surface receptors. Knowledge of the major stages in elastin assembly has facilitated the construction of in vitro models of elastogenesis, leading to the identification of precise molecular regions that are critical to elastin-based protein interactions.
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In order for signals generated at the plasma membrane to reach intracellular targets, activated messengers, such as G proteins and phosphoproteins, must diffuse through the cytoplasm. If the deactivators of these messengers, GTPase activating proteins (GAPs) and phosphatases, respectively, are sufficiently active in the cytoplasm, then the signal could in principle decay before reaching the target and a stable spatial gradient in phosphostate would be generated. Recent experiments document the existence of such gradients in living cells and suggest a role for them in mitotic spindle morphogenesis and cell migration. However, how such systems behave theoretically when embedded in a cell of varying size or shape has not been considered. Here we use a simple mathematical model to explore the theoretical consequences of a plasma membrane bound activator (i.e., guanine nucleotide exchange factor, GEF, or kinase) and a cytoplasmic deactivator (i.e., GAP or phosphatase), and we find that as a model cell grows, the substrate becomes progressively dephosphorylated as a result of decreased proximity to the activator. Conversely, as a cell spreads and flattens, the substrate becomes globally phosphorylated because of increased proximity of the substrate to the activator. Similarly, in the leading edge of polarized cells and in protrusions such as lamellipodia or filopodia, the substrate is highly phosphorylated. As a specific test of the model, we found that the experimentally observed preferential activation of the G protein Cdc42 in the periphery of fibroblasts that was recently reported is consistent with model predictions. We conclude that cell-signaling pathways can theoretically be turned on and off, both locally and globally, in response to alterations in cell size and shape.
2D and 3D cell cultures – a comparison of different types of cancer cell cultures
  • M Kapałczyńska
History of cell culture
  • M Jedrzejczak-Silicka