Cell biology
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20 Salerno, A, Oliviero, M, Di Maio, E, Iannace, S, Netti, PA (2009). Design of porous polymeric scaffolds by gas foaming of heterogeneous blends. J Mat Sci Mater Med, 20, 2043-2051. 21 Barbetta, A, Gumiero, A, Pecci, R, Bedini, R, Dentini, M (2009). Gas-in-liquid foam templating as a method for the production of highly porous scaffolds. Biomacromol. 10, 3188-3192. 22 Sun, T, Norton, D, McKean, RJ, Haycock, JW, Ryan, AJ, MacNeil, S (2007). Development of a 3D cell culture system for investigating cell interactions with electrospun fibers. Biotechnol Bioeng, 97, 1318-1328. 23 Dash, A, Inman, W, Hoffmaster, K, Sevidal, S, Kelly, J, Obach, RS, Griffith, LG, Tannenbaum, SR (2009). Liver tissue engineering in the evaluation of drug safety. Expert Opin Drug Metab Toxicol. 5, 1159-1174. 24 Bokhari, M, Carnachan, R, Cameron, NR, Przyborski, SA (2007). Novel cell culture device enabling three- dimensional cell growth and improved cell function. Biochem Biophys Res Comm, 354, 1095-1100. 25 Bokhari, Carnachan, Cameron, NR, Przyborski, SA (2007). Culture of HepG2 liver cells on three dimensional polystyrene scaffolds enhances cell structure and function during toxicological challenge. J Anat, 211, 567-76.
Figure 2: Emulsion templating can be used to generate highly porous materials such as this Alvetex™ polystyrene scaffold. The scaffold has been engineered into a 200 micron thick membrane shown in transverse section as imaged by scanning electron microscopy
and allowing for sufficient mass exchange of gases, nutrients and waste products during static culture. Alvetex™ membranes are designed to be incorpo- rated into existing cell culture products, such as welled plates or well inserts. Furthermore, like con- ventional 2D plastic ware, polystyrene-based scaf- folds are compatible with standard cell culture plasma treatment, gamma sterilisation methods and if required can be coated using standard cell culture reagents such as collagen, fibronectin, etc.
Conclusions
For 3D cell culture to become routine, the devel- opment of any new technology must consider issues such as cost, ease of use, application and
reproducibility, especially when the application is for drug discovery. A technology that is expen- sive, difficult to use or is inconsistent in some manner, will not satisfy these demands and will fail to be accepted by the scientific community. Importantly, any such technology requires vigor- ous exemplification and validation as evidence of its ability to support true 3D cell culture over a range of alternative cell types. For example, cul- tured liver cells are a valuable tool for the in vitro study of drug metabolism and toxicity23. Liver- derived cell lines represent a convenient model for liver toxicology studies, although commonly available lines often display poor metabolic responses when challenged with a toxicant. Growing hepatocytes in 3D using scaffold tech- nology, such as the application of Alvetex™ (Figure 3), can significantly enhance such responses24,25. Culture systems that show improved metabolic activity and/or more realistic resistance/sensitivity in response to specific drugs would be of significant value to the pharmaceuti- cal industry, enabling more accurate toxicological assays and increasing the predictive accuracy dur- ing compound screening.
In general the growth of cells on conventional 2D plastic substrates has not changed significantly for many years. New innovative ways of culturing cells are becoming available that will improve cur- rent practice, cell growth and performance. The evidence demonstrating the advantages of 3D cell growth is compelling, as is the need for technology that enables routine 3D cell culture. The invest- ment of time towards developing and validating such in vitro models is likely to significantly impact on the success and overall efficiency of pharma- ceutical development in the future.
DDW
Figure 3: Micrograph showing the structure of liver hepatocytes (HepG2) grown in 3D culture on a porous polystyrene scaffold. Sample prepared by histological methods and H&E counterstaining
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Professor Stefan Przyborski is the Founder and Chief Scientific Officer of Reinnervate Limited. He also holds an academic position at Durham University as Chair in Cell Technology. He has more than 18 years’ experience in cell biology, he manages a busy research group developing enabling technology to improve the growth and function of cells in vitro. Stefan publishes his work widely and frequently presents his research at sci- entific meetings.
Drug Discovery World Spring 2011
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