Towards osseointegration of bioinert ceramics: Can biological agents be immobilized on alumina substrates using self-assembled monolayer technique?

Immobilization of biological agents on inert alumina surfaces could promote bone growth and improve osseointegration. We hypothesize that functional groups on alumina surfaces can be used to link biological agents as a supporting factor e.g. for cell attachment. CH2, OH, COOH, and NH2 groups were linked to alumina surfaces using self-assembled monolayer technique (SAM). Subsequently, bovine serum albumin (BSA) was immobilized on each functionalized surface. Contact angle, bicinchoninic acid assay and immunofluorescence were used to detect immobilized BSA. The amount of BSA linked to functionalized surfaces increased in the following order CH2 < OH < COOH = NH2. The greatest amount, 26.1 μg/cm2 of BSA was found on both, NH2- and COOH-terminated surfaces. Cell tests confirmed cytocompatibility of all surfaces. The highest proliferation was detected on NH2-terminated samples. Using the model protein, the results confirmed feasibility for immobilization of biological agents to inert alumina ceramic surfaces using SAM technique.