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Biodegradable 3-dimensional scaffolds of various morphologies are currently being developed for tissue engineering. Poly(lactide-co-glycolide)s (PLGAs) of various lactide to glycolide ratios are frequently used for such applications. Tissue engineering involves an in vitro stage during which cells are seeded onto scaffolds and allowed to settle and/or grow for various time periods. To assess cell distribution and/or tissue formation throughout the scaffolds during this in vitro stage, techniques such as confocal microscopy and magnetic resonance imaging have been applied. However, such cultured scaffolds have been refractory to histological evaluation because of numerous technical difficulties. We describe a method to prepare histological sections of cell cultured PLGA scaffolds for tissue engineering. The technique involves in situ labeling of cultured scaffolds, infiltration of the scaffolds with a 10% poly(vinyl alcohol) solution under a low vacuum, and cryosectioning of samples onto acid-treated glass coverslips. Sections obtained with this technique show cell distribution and cell-tissue morphology on the pore wall structures of entire centimeter-thick scaffolds. This rapid and easy technique allows for fast evaluation of tissues grown on biodegradable scaffolds.

Thin ceramic films or coatings over metallic bone-interfacing implant surfaces have the potential to improve implant performance with respect to implant fixation, wear, or corrosion. In this study, zirconia (ZrO2) thin films formed on Ti-6AI-4V using a polymeric alkoxide-based solgel process were investigated. ZrO2 films of uniform thickness on the order of 100 nm were obtained by dip coating Ti-6AI-4V samples into a zirconium propoxide containing solution using a substrate withdrawal speed ranging from 2 to 8 cm/min and a sol of nominal viscosity approximately 6 cps. These films were essentially free of surface macrodefects but had random submicron "pinholes." X-ray diffraction studies suggested that the films were at least partially crystalline, with some "metastable" cubic and/or tetragonal phases after annealing for 1 h at 500 degrees C. The demonstrated reproducibility of this approach for producing good quality ZrO2 films on Ti-6AI-4V warrants further studies to optimize processing conditions for implant applications.

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