X-ray microcomputed tomography for the measurement of cell adhesion and proliferation in polymer scaffolds

We have explored the use of X-ray microcomputed tomography (mu CT) for assessing cell adhesion and proliferation in polymer scaffolds. Common methods for examining cells in scaffolds include fluorescence microscopy and soluble assays for cell components such as enzymes, protein or DNA. Fluorescence microscopy is generally qualitative and cannot visualize the scaffold interior. Soluble assays quantitatively measure cell number but do not yield information on cell spatial distribution. Herein, the ability of mu CT to detect cells in scaffolds was compared with fluorescence microscopy and a soluble DNA assay. Comparisons were performed using polymer scaffolds that were seeded with cells at different densities and cultured for different times. The results showed that fluorescence microscopy had better resolution than mu CT and that the soluble DNA assay was approximately 5x more sensitive than mu CT under the conditions tested. However, mu CT was able to image through opaque scaffolds to yield quantitative 3D imaging and analysis via a single, non-invasive modality. Quantitative mu CT analysis of cell penetration into scaffolds was demonstrated. Further, quantitative mu CT volume analysis required that the cell density in the scaffolds be greater than 1 million cells per mL indicating that mu CT is best suited for quantifying cells at relatively high density during culture in scaffolds. In sum, the results demonstrate the benefits and limitations of using mu CT for 3D imaging and analysis of cell adhesion and proliferation in polymer scaffolds. Published by Elsevier Ltd.