ARTICLE Human Bone Derived Cell Culture on PLGA Flat Sheet Membranes of Different Lactide:Glycolide Ratio Marianne J. Ellis, Julian B. Chaudhuri Department of Chemical Engineering, Centre for Regenerative Medicine, University of Bath, Bath BA2 7AY, UK; telephone: þ44-1225-384484; fax: þ44-1225-385713; e-mail: m.j.ellis@bath.ac.uk Received 24 October 2007; revision received 6 March 2008; accepted 11 March 2008 Published online 19 March 2008 in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/bit.21902 ABSTRACT: Providing a scaffold that can supply nutrients on a large scale (several cubic centimeters) is the key to successfully regenerating vascularized tissue: biodegradable membranes are a promising new scaffold suited to this purpose. Poly(lactic-co-glycolic-acid) (PLGA) flat sheet membranes of different lactide:glycolide ratios, prepared by phase inversion using 1-methyl-2-pyrrolidinone (NMP) as the solvent and water as the nonsolvent, were compared by assessing attachment, proliferation and osteogenic func- tion of human bone derived cells (HBDC). Three different lactide:glycolide ratios, 50:50, 75:25, and 100:0, were com- pared to tissue culture polystyrene (TCPS). For attachment, 50:50 and 75:25 had similar numbers to TCPS but 100:0 had significantly fewer cells than TCPS. 50:50 and 75:25 had significantly lower HBDC numbers after 7 days but 100:0 had similar numbers compared to TCPS. For proliferation the cell number on the membranes were similar to each other. After 3 weeks, osteoblastic function of the HBDC, shown by mineralization and alkaline phosphatase activity, was present but was significantly lower compared to the TCPS control but similar when the membranes were com- pared. PLGA membranes fabricated from a range of ratios support HBDC culture so the optimum scaffold composition can be selected based on other factors, such as degradation rate. Biotechnol. Bioeng. 2008;101: 369–377. ß 2008 Wiley Periodicals, Inc. KEYWORDS: bone tissue engineering; cell adhesion; mem- brane; polyglycolic acid; polylactic acid; scaffold Introduction When growing bone in vitro it is necessary to provide an artificial extracellular matrix (ECM) to initiate growth and organization of nascent tissue. Surface characteristics and topography, surface chemistry and treatment, and degrada- tion characteristics of the scaffold all affect bone cell viability, attachment and spreading (Sikavitsas et al., 2001). The ideal scaffold should be designed to replicate the natural ECM when considering mechanotransduction, vasculariza- tion, nutrient and waste transport, attachment, migration and, differentiation and remodeling. There are many chemical, mechanical and architectural characteristics that a scaffold should possess including no immune response, ability to incorporate ligands for attachment or growth factors (Burg et al., 2000), degrade into easily removed products at the required rate; resist physiological forces exerted by the body; should react to forces in a similar way to real bone to prevent stress points and provide the appropriate signals for mechanotransduc- tion; the macrostructure should be easily manipulated for implant; microstructure-pore size, porosity, pore shape, pore geometry should resemble the particular section of bone it is replacing. In addition to these properties, the scaffolds should be cheap to manufacture, and easily reproducible. It also needs to be available at short notice (Peter et al., 1998). There is a range of potential material that bone tissue engineering scaffolds can be made from, includ- ing natural and synthetic polymers, ceramics and glasses, metals, hydrogels and combinations of these materials (Gibson, 2003; Yang et al., 2001). These materials can be fabricated into a variety of macro-architectures such as films, porous foams/sponges (Kokubo et al., 2003), electro- spun nonwoven sheets (Yoshimoto et al., 2003), micro- spheres (Botchwey et al., 2001), dipcoating tubes (Wan et al., 2001), non-hollow fibers (Williamson and Coombes, 2004), hollow fibers, porous particles (Jin et al., 2000) and extruded channeled-blocks (Hadlock et al., 2000; Jin et al., 2000). The most common, well studied and successful materials used in bone tissue engineering is hydroxyapatite and the range of poly(alpha-hydroxy acids); poly(lactic acid) (PLA), poly(glycolic acid) (PGA) and the copolymer of the two, poly(lactic-co-glycolic acid) (PLGA). PLGA is known to be suitable as a scaffold material due to its previous use in sutures and fixation devices; it is US FDA approved and the Correspondence to: M.J. Ellis ß 2008 Wiley Periodicals, Inc. Biotechnology and Bioengineering, Vol. 101, No. 2, October 1, 2008 369