Evaluation of bioresorbable polymers of lactic acid in a culture of human bone marrow cells

Long term cultures of human bone marrow cells on poly(L-lactide-co-D.L-lact ide) 70:30 and 90:10 plates were observed by means of scanning electron mic roscopy (SEM), SEM-EDX (SEM combined with energy dispersive X-ray analysis) , flow cytometry, histochemical stainings, and culture medium analysis. Aft er 14 days culture, cell numbers were only slightly lower compared with our reference material. hydroxyapatite, and much higher compared with polyethy lene. There was evidence of collagenous matrix production with osteoblast a ctivity. Acridine orange stainings as well as flow cytometry after incubati on with propidium iodide showed only a few non-viable cells. By means of fl ow cytometry. we found about 30% of cells with granulocyte-markers. some mo nocyte-derived cells. and only small amounts of lymphocytes. After 9 weeks culture, there was evidence of calcium-phosphate deposition with extracellu lar matrix. There were only slight differences between the two tested polym ers, Our culture system with human bone marrow cells plated on two bioresor bable polymers suggests a biocompatibility almost as good as hydroxyapatite , which is usually well tolerated. There was even evidence of mineralized c ollagenous matrix after some weeks of culture, which was detected earlier t han the mineralization of cell-fret controls.