Bioactive membrane immobilized with lactoferrin for modulation of bone regeneration and inflammation

Abstract

Guided bone regeneration refers to the process in which bone defects could be regenerated by facilitated healing through the use of membranes, potentially with the delivery of osteoinductive molecules, however, the regeneration often failed due to inflammation during bone formation. In this study, we developed a membrane immobilized with lactoferrin to modulate both bone regeneration and inflammatory responses. Lactoferrin was immobilized on electrospun nanofibers (LF50) by exploiting an adhesive polydopamine coating method. When human adipose-derived stem cells (hADSCs) were seeded onto the nanofibers, the LF50 significantly increased the osteogenic differentiation. For example, the gene expression of osteopontin was 6.9 - 2.3 times greater in the cells on LF50 than the cells on unmodified nanofibers without lactoferrin. In addition, the gene expression of tumor necrosis factor-alpha (TNF-a) of the macrophage cell line (RAW264.7) cultured on the LF50 was 0.3 - 0.1 times reduced, indicating the lactoferrin was able to reduce inflammatory response. With implantation of nanofibers on in vivo mouse calvarial defects, the LF50 resulted in 60.9% - 4.5% of new bone formation, which was six times greater than the results of other groups. Furthermore, when the fibers were implanted onto the in vivo mouse subcutaneous model challenged with lipopolysaccharide and interferon-g, the area of inflammatory tissue was significantly reduced in the LF50 implanted group as 0.6 - 0.1 mm2 as compared with the control group (1.1 - 0.1 mm2). Taken together, the lactoferrin immobilization onto the nanofiber by polydopamine chemistry may be an effective delivery method for improving bone regeneration while regulating the inflammation.