A novel bone graft substitute comprising a porous, collagenous scaffold was biomimetically coated with hydroxyapatite using a simulated body fluid solution chemistry method. The scaffold had a porosity of approximately 85%, with pore sizes between 30 μm and 100 μm. Glutaraldehyde vapor was used to stabilize the collagenous scaffold, giving a significantly increased thermal stability over an unstabilized scaffold, as shown by differential scanning calorimetry. A thin layer (<10 μm) of crystalline hydroxyapatite was deposited onto the stabilized collagenous scaffold by soaking the collagenous construct in simulated body fluid in the presence of calcium silicate glass. The presence of crystalline hydroxyapatite was confirmed by X‐ray diffraction, energy‐dispersive X‐ray spectroscopy, and scanning electron microscopy. In vitro cytotoxicity testing of the composite construct using L‐929 fibroblasts (ISO 10993‐5) and rabbit periosteal cells revealed a cytocompatible material that supported cellular attachment and proliferation. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 68A: 19–27, 2004

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