Oleic acid-added embedding medium for histological analysis of hard tissue

For the histological analysis of hard tissue such as bone, various acrylate-based materials have been used as an embedding medium. However, commercial embedding media are expensive, and cutting the embedded block takes a long time. In this study, mixtures of methyl methacrylate (MMA), di-butyl-phthalate (DBP), and oleic acid (OA) were tested for possible application as an embedding medium for large and small undecalcified bone specimens. Mechanical properties were tested in a compressive mode. We investigated the change of hydrophilicity in the sectioned surface by measuring the contact angle depending on the OA. Crystallinity was analyzed using a X-ray diffractometer (XRD). Surface analysis was performed using a confocal laser scanning microscope. To determine the staining efficiency of staining dyes, hamatoxylin-eosin (H&E) and Masson's trichrome (MT) staining methods were performed for the histological analysis of bone-implant complex. We confirmed that the investigated embedding media showed good properties such as optimal mechanical strength appropriate for cutting the embedded block and proper staining efficiency for histological analysis. Therefore, the MMA/DBP/OA mixtures can be used as an embedding media appropriate for various hard tissues and bone-implant complex.