Atomic force microscopy for high resolution imaging of collagen fibrils - A new technique to investigate collagen structure in historic bone tissues

In this study, we present a new technique for the structural analysis of th e collagen compound in historic tissues. We therefore used atomic force mic roscopy (AFM), a new high resolution technique which offers significant inf ormation on the fibrillar assembly and ultrastructure of collagen fibrils, which may provide insight into both the physiological and eventually pathog enic patterns of collagen fibrils, but also into possible diagenetic destru ctive changes of those fibrils. AFM figures three-dimensionally the surface of a sample with high resolution down to a nanometer scale. In our investi gation we used the AFM to image paraffin embedded tissue sections from femo ral bone tissue of a recent case and an age determined historic sample in a mbient conditions. With this technique we were able to identify unambiguous ly collagen bundles and to determine their diameter. These results led us t o differentiate the bundling pattern of collagen type 1 from that of collag en type II. In addition, we identified collagen type I in the historic samp le, which provided a fibrillar pattern as that of recent bone. The results were compared to standard immunohistochemical staining techniques of the re spective collagen types. In conclusion, our study presents circumstantial e vidence that AFM analysis as a novel morphological tehcnique can successful ly be applied to historic tissues specimens.