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A fibroblast is a type of biological cell that synthesizes the extracellular matrix and collagen, produces the structural framework (stroma) for animal tissues, and plays a critical role in wound healing. Fibroblasts are the most common cells of connective tissue in animals.
Tissue engineering is a biomedical engineering discipline that uses a combination of cells, engineering, materials methods, and suitable biochemical and physicochemical factors to restore, maintain, improve, or replace different types of biological tissues. Tissue engineering often involves the use of cells placed on tissue scaffolds in the formation of new viable tissue for a medical purpose but is not limited to applications involving cells and tissue scaffolds. While it was once categorized as a sub-field of biomaterials, having grown in scope and importance it can be considered as a field of its own.
Tissue culture is the growth of tissues or cells in an artificial medium separate from the parent organism. This technique is also called micropropagation. This is typically facilitated via use of a liquid, semi-solid, or solid growth medium, such as broth or agar. Tissue culture commonly refers to the culture of animal cells and tissues, with the more specific term plant tissue culture being used for plants. The term "tissue culture" was coined by American pathologist Montrose Thomas Burrows. This is possible only in certain conditions. It also requires more attention. It can be done only in genetic labs with various chemicals.
Organ culture is the cultivation of either whole organs or parts of organs in vitro. It is a development from tissue culture methods of research, as the use of the actual in vitro organ itself allows for more accurate modelling of the functions of an organ in various states and conditions.
Plant callus is a growing mass of unorganized plant parenchyma cells. In living plants, callus cells are those cells that cover a plant wound. In biological research and biotechnology callus formation is induced from plant tissue samples (explants) after surface sterilization and plating onto tissue culture medium in vitro. The culture medium is supplemented with plant growth regulators, such as auxin, cytokinin, and gibberellin, to initiate callus formation or somatic embryogenesis. Callus initiation has been described for all major groups of land plants.
Cell culture or tissue culture is the process by which cells are grown under controlled conditions, generally outside of their natural environment. The term "tissue culture" was coined by American pathologist Montrose Thomas Burrows. This technique is also called micropropagation. After the cells of interest have been isolated from living tissue, they can subsequently be maintained under carefully controlled conditions. They need to be kept at body temperature (37 °C) in an incubator. These conditions vary for each cell type, but generally consist of a suitable vessel with a substrate or rich medium that supplies the essential nutrients (amino acids, carbohydrates, vitamins, minerals), growth factors, hormones, and gases (CO2, O2), and regulates the physio-chemical environment (pH buffer, osmotic pressure, temperature). Most cells require a surface or an artificial substrate to form an adherent culture as a monolayer (one single-cell thick), whereas others can be grown free floating in a medium as a suspension culture. This is typically facilitated via use of a liquid, semi-solid, or solid growth medium, such as broth or agar. Tissue culture commonly refers to the culture of animal cells and tissues, with the more specific term plant tissue culture being used for plants. The lifespan of most cells is genetically determined, but some cell-culturing cells have been “transformed” into immortal cells which will reproduce indefinitely if the optimal conditions are provided.
Micropropagation or tissue culture is the practice of rapidly multiplying plant stock material to produce many progeny plants, using modern plant tissue culture methods.
Regenerative medicine deals with the "process of replacing, engineering or regenerating human or animal cells, tissues or organs to restore or establish normal function". This field holds the promise of engineering damaged tissues and organs by stimulating the body's own repair mechanisms to functionally heal previously irreparable tissues or organs.
Matrigel is the trade name for the solubilized basement membrane matrix secreted by Engelbreth-Holm-Swarm (EHS) mouse sarcoma cells produced by Corning Life Sciences. Matrigel resembles the laminin/collagen IV-rich basement membrane extracellular environment found in many tissues and is used by cell biologists as a substrate for culturing cells.
Adult stem cells are undifferentiated cells, found throughout the body after development, that multiply by cell division to replenish dying cells and regenerate damaged tissues. Also known as somatic stem cells, they can be found in juvenile, adult animals, and humans, unlike embryonic stem cells.
Perlecan (PLC) also known as basement membrane-specific heparan sulfate proteoglycan core protein (HSPG) or heparan sulfate proteoglycan 2 (HSPG2), is a protein that in humans is encoded by the HSPG2 gene. The HSPG2 gene codes for a 4,391 amino acid protein with a molecular weight of 468,829. It is one of the largest known proteins.
An organoid is a miniaturized and simplified version of an organ produced in vitro in three dimensions that mimics the key functional, structural and biological complexity of that organ. They are derived from one or a few cells from a tissue, embryonic stem cells or induced pluripotent stem cells, which can self-organize in three-dimensional culture owing to their self-renewal and differentiation capacities. The technique for growing organoids has rapidly improved since the early 2010s, and The Scientist names it as one of the biggest scientific advancements of 2013. Scientists and engineers use organoids to study development and diseases in the laboratory and industry for drug discovery and development, personalized diagnostics and medicine, gene and cell therapies, tissue engineering and regenerative medicine.
In tissue engineering, neo-organ is the final structure of a procedure based on transplantation consisting of endogenous stem/progenitor cells grown ex vivo within predesigned matrix scaffolds. Current organ donation faces the problems of patients waiting to match for an organ and the possible risk of the patient's body rejecting the organ. Neo-organs are being researched as a solution to those problems with organ donation. Suitable methods for creating neo-organs are still under development. One experimental method is using adult stem cells, which use the patients own stem cells for organ donation. Currently this method can be combined with decellularization, which uses a donor organ for structural support but removes the donors cells from the organ. Similarly, the concept of 3-D bioprinting organs has shown experimental success in printing bioink layers that mimic the layer of organ tissues. However, these bioinks do not provide structural support like a donor organ. Current methods of clinically successful neo-organs use a combination of decellularized donor organs, along with adult stem cells of the organ recipient to account for both the structural support of a donor organ and the personalization of the organ for each individual patient to reduce the chance of rejection.
Dermal fibroblasts are cells within the dermis layer of skin which are responsible for generating connective tissue and allowing the skin to recover from injury. Using organelles, dermal fibroblasts generate and maintain the connective tissue which unites separate cell layers. Furthermore, these dermal fibroblasts produce the protein molecules including laminin and fibronectin which comprise the extracellular matrix. By creating the extracellular matrix between the dermis and epidermis, fibroblasts allow the epithelial cells of the epidermis to affix the matrix, thereby allowing the epidermal cells to effectively join together to form the top layer of the skin.
Induced stem cells (iSC) are stem cells derived from somatic, reproductive, pluripotent or other cell types by deliberate epigenetic reprogramming. They are classified as either totipotent (iTC), pluripotent (iPSC) or progenitor or unipotent – (iUSC) according to their developmental potential and degree of dedifferentiation. Progenitors are obtained by so-called direct reprogramming or directed differentiation and are also called induced somatic stem cells.
A cerebral organoid, or brain organoid, describes an artificially grown, in vitro, miniature organ resembling the brain. Cerebral organoids are created by culturing pluripotent stem cells in a three-dimensional rotational bioreactor, and they develop over a course of months. The brain is an extremely complex system of heterogeneous tissues and consists of a diverse array of neurons. This complexity has made studying the brain and understanding how it works a difficult task in neuroscience, especially when it comes to neurodegenerative diseases. The purpose of creating an in vitro neurological model is to study these diseases in a more simple and variable space. This 3D model is free of many potential in vivo limitations. The varying physiology between human and other mammalian models limits the scope of study in neurological disorders. Cerebral organoids are synthesized tissues that contain several types of nerve cells and have anatomical features that recapitulate regions of the cortex observed in brains. Cerebral organoids are most similar to layers of neurons called the cortex and choroid plexus. In some cases, structures similar to the retina, meninges and hippocampus can form. Stem cells have the potential to grow into many different types of tissues, and their fate is dependent on many factors. Below is an image showing some of the chemical factors that can lead stem cells to differentiate into various neural tissues; a more in-depth table of generating specific organoid identity has been published since. Similar techniques are used on stem cells used to grow cerebral organoids.
The in vivo bioreactor is a tissue engineering paradigm that uses bioreactor methodology to grow neotissue in vivo that augments or replaces malfunctioning native tissue. Tissue engineering principles are used to construct a confined, artificial bioreactor space in vivo that hosts a tissue scaffold and key biomolecules necessary for neotissue growth. Said space often requires inoculation with pluripotent or specific stem cells to encourage initial growth, and access to a blood source. A blood source allows for recruitment of stem cells from the body alongside nutrient delivery for continual growth. This delivery of cells and nutrients to the bioreactor eventually results in the formation of a neotissue product.
Directed differentiation is a bioengineering methodology at the interface of stem cell biology, developmental biology and tissue engineering. It is essentially harnessing the potential of stem cells by constraining their differentiation in vitro toward a specific cell type or tissue of interest. Stem cells are by definition pluripotent, able to differentiate into several cell types such as neurons, cardiomyocytes, hepatocytes, etc. Efficient directed differentiation requires a detailed understanding of the lineage and cell fate decision, often provided by developmental biology.
Hydrogel from wood-based nanofibrillated cellulose (NFC) is used as a matrix for 3D cell culture, providing a three-dimensional environment that more closely resembles the conditions found in living tissue. As plant based material, it does not contain any human- or animal-derived components. Nanocellulose is instead derived from wood pulp that has been processed to create extremely small, nanoscale fibers. These fibers can be used to create a hydrogel, which is a type of material that is made up of a network of cross-linked polymer chains and is able to hold large amounts of water.
Primary cell culture is the ex vivo culture of cells freshly obtained from a multicellular organism, as opposed to the culture of immortalized cell lines. In general, primary cell cultures are considered more representative of in vivo tissues than cell lines, and this is recognized legally in some countries such as the UK. However, primary cells require adequate substrate and nutrient conditions to thrive and after a certain number of divisions they acquire a senescent phenotype, leading to irreversible cell cycle arrest. The generation of cell lines stems from these two reasons. Primary cells can become immortalized either spontaneously or by genetic modification, at which point they become cell lines which can be subcultured indefinitely.
References
- 1 2 3 4 "Explant Culture for Developmental Studies | Protocol". www.jove.com. Retrieved 2017-05-25.
- 1 2 "Explant Culture of Neural Tissue". JoVE Science Education Database.
- ↑ Orth MW et al. (2000) Cartilage turnover in embryonic chick tibial explant cultures. Poult Sci 79:990-993.
- ↑ Ivan Bedzhov, Magdalena Zernicka-Goetz.(2014). Self-Organizing Properties of Mouse Pluripotent Cells Initiate Morphogenesis upon Implantation. Cell,; DOI: 10.1016/j.cell.2014.01.023
- ↑ Hunter, Philip (2017-05-25). "One organ at a time: Research has been making much progress to create in vitro human tissues for transplantation but laboratory-grown complex organs still remain decades away". EMBO Reports. 15 (3): 227–230. doi:10.1002/embr.201438528. ISSN 1469-221X. PMC 3989688 . PMID 24554301.
- ↑ Garg, Aakriti; Yang, Jin; Lee, Winston; Tsang, Stephen H. (2017-02-02). "Stem Cell Therapies in Retinal Disorders". Cells. 6 (1): 4. doi: 10.3390/cells6010004 . PMC 5371869 . PMID 28157165.