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A clusteroid is a method of producing 3D cell cultures that was first developed in 2019. [1] Clusteroids are grown as not true spheroids but as dense clusters of cells in an aqueous two-phase system of water-in-water Pickering emulsion. The cells are incapsulated by mixing two aqueous solutions containing the incompatible polymers: Polyethylene oxide (PEO) solution as a continuous phase and dextran solution (DEX) as a dispersed phase, using whey protein as a stabiliser. [1] [2] Clusteoids as an in vitro model are more accurate to the complexities of in vivo , and aren't as susceptible to some of the problems 2D cultures present, for example; A large problem in culturing cells as a 2D monolayer is confluence as most cell lines used in research tend to decline in growth and health above 80% due to competition between cells for nutrients and oxygen in their growth media. [3] A unique problem in non-vascularised clusteroids is necrotic core formation; as nutrients and oxygen cannot diffuse into the centre of the clusteroid without other cells taking it up, the cells within become starved and subsequently die. This necrotic core formation is similar to that of poorly-vascularised solid tumours. [4] [5]
Co-culture clusteroids are clusteroids that are composed of multiple different cell lines or types. [2] [6]
The DEX phase containing cells and the PEO phase containing whey protein particles is emulsified, encapsulating the cells in a DEX-PEO water-in-water emulsion template stabilized by whey protein particles. Additional PEO is then added to efflux the water from the DEX phase, causing osmotic shrinking of the cell-rich dextran droplets. The interfacial tension between the two phases packs the cells into tissue clusteroids. The emulsion is then broken by dilution with culture media and the gelling agent sodium alginate and a calcium chloride solution is then added to form a hydrogel. The clusteroids are then incubated in the gel for up to 7 days to form tissues or organoids. Finally the gel is reverted by into liquid form by alginate lyase. [7] [1]
Co-culture clusteroids have been used in research into angiogenesis; vascularised clusteroids do not develop necrotic core formation as vessels created allow for perfusion of nutrients and oxygen into the centre of the clusteroid to occur, preventing cell death. [2] Angiogenesis is initiated by pro-angiogenic growth factors such as vascular endothelial growth factor (VEGF), which is either exogenous or secreted by cells within the clusteroid, depending on the cells cultured. Clusteroids demonstrate tube and vessel formation in vitro . [6] Use of Co-culture clusteroids as opposed to culturing separately leads to increased expression of angiogenesis-related genes demonstrating an impact of heterogeneity on cancer [1]
An emulsion is a mixture of two or more liquids that are normally immiscible owing to liquid-liquid phase separation. Emulsions are part of a more general class of two-phase systems of matter called colloids. Although the terms colloid and emulsion are sometimes used interchangeably, emulsion should be used when both phases, dispersed and continuous, are liquids. In an emulsion, one liquid is dispersed in the other. Examples of emulsions include vinaigrettes, homogenized milk, liquid biomolecular condensates, and some cutting fluids for metal working.
Angiogenesis is the physiological process through which new blood vessels form from pre-existing vessels, formed in the earlier stage of vasculogenesis. Angiogenesis continues the growth of the vasculature mainly by processes of sprouting and splitting, but processes such as coalescent angiogenesis, vessel elongation and vessel cooption also play a role. Vasculogenesis is the embryonic formation of endothelial cells from mesoderm cell precursors, and from neovascularization, although discussions are not always precise. The first vessels in the developing embryo form through vasculogenesis, after which angiogenesis is responsible for most, if not all, blood vessel growth during development and in disease.
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.
A blood substitute is a substance used to mimic and fulfill some functions of biological blood. It aims to provide an alternative to blood transfusion, which is transferring blood or blood-based products from one person into another. Thus far, there are no well-accepted oxygen-carrying blood substitutes, which is the typical objective of a red blood cell transfusion; however, there are widely available non-blood volume expanders for cases where only volume restoration is required. These are helping doctors and surgeons avoid the risks of disease transmission and immune suppression, address the chronic blood donor shortage, and address the concerns of Jehovah's Witnesses and others who have religious objections to receiving transfused blood.
Wound healing refers to a living organism's replacement of destroyed or damaged tissue by newly produced tissue.
In colloidal chemistry, flocculation is a process by which colloidal particles come out of suspension to sediment in the form of floc or flake, either spontaneously or due to the addition of a clarifying agent. The action differs from precipitation in that, prior to flocculation, colloids are merely suspended, under the form of a stable dispersion and are not truly dissolved in solution.
Microencapsulation is a process in which tiny particles or droplets are surrounded by a coating to give small capsules, with useful properties. In general, it is used to incorporate food ingredients, enzymes, cells or other materials on a micro metric scale. Microencapsulation can also be used to enclose solids, liquids, or gases inside a micrometric wall made of hard or soft soluble film, in order to reduce dosing frequency and prevent the degradation of pharmaceuticals.
Easy Cheese is the trademark for a processed cheese spread product distributed by Mondelēz International. It is also commonly referred to by generic terms such as "spray cheese", "squirt cheese", "cheese in a can", and/or "cheese cans". Easy Cheese is packaged in a metal can filled with air covered with a plastic cap that reveals a straight, flexible nozzle where the cheese is extruded.
Aqueous biphasic systems (ABS) or aqueous two-phase systems (ATPS) are clean alternatives for traditional organic-water solvent extraction systems.
Poloxamers are nonionic triblock copolymers composed of a central hydrophobic chain of polyoxypropylene flanked by two hydrophilic chains of polyoxyethylene. The word poloxamer was coined by BASF inventor, Irving Schmolka, who received the patent for these materials in 1973. Poloxamers are also known by the trade names Pluronic, Kolliphor, and Synperonic.
A Ramsden emulsion, sometimes named Pickering emulsion, is an emulsion that is stabilized by solid particles which adsorb onto the interface between the water and oil phases. Typically, the emulsions are either water-in-oil or oil-in-water emulsions, but other more complex systems such as water-in-water, oil-in-oil, water-in-oil-in-water, and oil-in-water-in-oil also do exist. Pickering emulsions were named after S.U. Pickering, who described the phenomenon in 1907, although the effect was first recognized by Walter Ramsden in 1903.
The lithium–air battery (Li–air) is a metal–air electrochemical cell or battery chemistry that uses oxidation of lithium at the anode and reduction of oxygen at the cathode to induce a current flow.
Peptide amphiphiles (PAs) are peptide-based molecules that self-assemble into supramolecular nanostructures including; spherical micelles, twisted ribbons, and high-aspect-ratio nanofibers. A peptide amphiphile typically comprises a hydrophilic peptide sequence attached to a lipid tail, i.e. a hydrophobic alkyl chain with 10 to 16 carbons. Therefore, they can be considered a type of lipopeptide. A special type of PA, is constituted by alternating charged and neutral residues, in a repeated pattern, such as RADA16-I. The PAs were developed in the 1990s and the early 2000s and could be used in various medical areas including: nanocarriers, nanodrugs, and imaging agents. However, perhaps their main potential is in regenerative medicine to culture and deliver cells and growth factors.
A nanocapsule is a nanoscale shell made from a nontoxic polymer. They are vesicular systems made of a polymeric membrane which encapsulates an inner liquid core at the nanoscale. Nanocapsules have many uses, including promising medical applications for drug delivery, food enhancement, nutraceuticals, and for self-healing materials. The benefits of encapsulation methods are for protection of these substances to protect in the adverse environment, for controlled release, and for precision targeting. Nanocapsules can potentially be used as MRI-guided nanorobots or nanobots, although challenges remain.
A 3D cell culture is an artificially created environment in which biological cells are permitted to grow or interact with their surroundings in all three dimensions. Unlike 2D environments, a 3D cell culture allows cells in vitro to grow in all directions, similar to how they would in vivo. These three-dimensional cultures are usually grown in bioreactors, small capsules in which the cells can grow into spheroids, or 3D cell colonies. Approximately 300 spheroids are usually cultured per bioreactor.
MC2 Biotek is a biotechnology company established in 2006, with offices in Denmark and external labs in the United Kingdom. MC2 is a holding company, comprising three smaller Biotechnology companies with their own biotechnology solutions, they are: DrugMode (DK), Zadec (DK), and Drug Delivery Solutions (UK). DrugMode specializes in 3D cell culture, and is based out of the University of Southern Denmark at Odense. Zadec focuses on Diabetes and nutrition, and has developed an oral anti-diabetes drug, RX-1, which is currently in clinical trials. Drug Delivery Solutions works in the field of dermatology and ophthalmology, developing topical drugs such as a cream to treat psoriasis.
Microfluidic cell culture integrates knowledge from biology, biochemistry, engineering, and physics to develop devices and techniques for culturing, maintaining, analyzing, and experimenting with cells at the microscale. It merges microfluidics, a set of technologies used for the manipulation of small fluid volumes within artificially fabricated microsystems, and cell culture, which involves the maintenance and growth of cells in a controlled laboratory environment. Microfluidics has been used for cell biology studies as the dimensions of the microfluidic channels are well suited for the physical scale of cells. For example, eukaryotic cells have linear dimensions between 10 and 100 μm which falls within the range of microfluidic dimensions. A key component of microfluidic cell culture is being able to mimic the cell microenvironment which includes soluble factors that regulate cell structure, function, behavior, and growth. Another important component for the devices is the ability to produce stable gradients that are present in vivo as these gradients play a significant role in understanding chemotactic, durotactic, and haptotactic effects on cells.
Droplet-based microfluidics manipulate discrete volumes of fluids in immiscible phases with low Reynolds number and laminar flow regimes. Interest in droplet-based microfluidics systems has been growing substantially in past decades. Microdroplets offer the feasibility of handling miniature volumes of fluids conveniently, provide better mixing, encapsulation, sorting, sensing and are suitable for high throughput experiments. Two immiscible phases used for the droplet based systems are referred to as the continuous phase and dispersed phase.
Cultrex Basement Membrane Extract (BME) is the trade name for a extracellular protein mixture secreted by Engelbreth-Holm-Swarm (EHS) mouse sarcoma cells and manufactured into a hydrogel by R&D Systems, a brand of Bio-Techne. Similar to Matrigel, this hydrogel is a natural extracellular matrix that mimics the complex extracellular environment within complex tissues. It is used as a general cell culture substrate across a wide variety of research applications.
Topical cream formulation is an emulsion semisolid dosage form that is used for skin external application. Most of the topical cream formulations contain more than 20 per cent of water and volatiles and/or less than 50 per cent of hydrocarbons, waxes, or polyethylene glycols as the vehicle for external skin application. In a topical cream formulation, ingredients are dissolved or dispersed in either a water-in-oil (W/O) emulsion or an oil-in-water (O/W) emulsion. The topical cream formulation has a higher content of oily substance than gel, but a lower content of oily ingredient than ointment. Therefore, the viscosity of topical cream formulation lies between gel and ointment. The pharmacological effect of the topical cream formulation is confined to the skin surface or within the skin. Topical cream formulation penetrates through the skin by transcellular route, intercellular route, or trans-appendageal route. Topical cream formulation is used for a wide range of diseases and conditions, including atopic dermatitis (eczema), psoriasis, skin infection, acne, and wart. Excipients found in a topical cream formulation include thickeners, emulsifying agents, preservatives, antioxidants, and buffer agents. Steps required to manufacture a topical cream formulation include excipient dissolution, phase mixing, introduction of active substances, and homogenization of the product mixture.