| Feb 18, 2015 |
An entirely new approach to tissue engineering
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(Nanowerk News) While there are many pre-existing strategies for fabricating and printing biomaterial scaffolds and hydrogels laden with low densities of cells, many tissues are predominantly comprised of cells with minimal material separating the cells.
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Currently, methods to prepare such scaffold-free, cell-only constructs are limited to iterative assembly of spheroids into aggregates, magnetic levitation culture of artificially magnetized cells, or temporary formation of cell sheets, all of which have inherent limitations.
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One of the most frequently used approaches for fabricating cell-rich constructs is the use of poly( N -isopropylacrilamide) (NIPAM)-modified thermoresponsive substrates. NIPAM-modified substrates promote cell adhesion at physiological temperatures (∼37°C) and release cells when the temperature is lowered below 22°C.
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However, this technology requires that cells be grown for a period of at least several days to establish the appropriate cell-cell connections, requires extensive and costly cell substrate engineering, and can fail if appropriate temperature conditions are not met. These requirements present potential limitations when rapid treatment is needed.
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Research on in vitro organ models and tissue replacement therapies, therefore, would benefit from a faster, simpler, and less-expensive general procedure that can create macroscopic cell-only constructs.
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Now, researchers have developed a new approach that meets these general demands by assembling multiple types of cell
suspensions into free-standing, centimeter-scale constructs at the interface between phase-separating aqueous solutions containing poly(ethylene glycol) and dextran in as little as 2 hours ("Rapid Self-Assembly of Macroscale Tissue Constructs at Biphasic Aqueous Interfaces").
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This novel cell construct formation method is complementary to NIPAM-engineered cell sheets and other methods for cell construct fabrication, while providing advantages in terms of the speed at which the constructs form (several hours), the relative simplicity of the procedure, the range of cell types that can be used, and cost effectiveness.
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