Bisphosphonate-based surface biofunctionalization improves titanium biocompatibility.

Novel-biofunctionalized surfaces are required to improve the performance of endosseous implants, which are mainly related to the resistance against biocorrosion, as well as for the consideration of osteoinductive phenomena. Among different strategies, the use of bisphosphonate molecules as linkers between titanium dioxide (TiO2) surfaces and proteins is a distinctive approach, one in which bisphosphonate could play a role in the osseointegration. Thus, to address this issue, we proposed a novel biofunctionalization of TiO2 surfaces using sodium alendronate (ALN) as a linker and bovine serum albumin as the protein. Physicochemical analysis of the functionalized surfaces was performed using contact angle analyses and surface roughness measurements, which indicated an efficient functionalization. The biocompatibility of the functionalized surfaces was analyzed through the adhesion behavior of the pre-osteoblasts onto the samples. Overall, our data showed a significant improvement concerning the cell adhesion by modulating the adhesion cell-related set of genes. The obtained results show that for modified surfaces there is an increase of up to 100 times in the percentage of cells adhered when compared to the control, besides the extracellular matrix remodeling seemed to be an essential prerequisite for the early stages of cell adhesion on to the biomaterials, which was assayed by evaluating the matrix metalloproteinase activities as well as the gene activations. In the expressions of the Bsp and Bglap2 genes, for the group containing ALN (TiO2 + ALN), it was observed an increase in expression (approximately sixfold change) when compared to the control. Altogether, our data clearly showed that the bisphosphonate-biofunctionalized surface enhanced the biocompatibility of titanium and claims to further progress preclinical in vivo experimentation.

Publisher Correction: Bisphosphonate-based surface biofunctionalization improves titanium biocompatibility.

A Correction to this paper has been published: https://doi.org/10.1007/s10856-020-06470-x.

Biofunctionalization of titanium surfaces with alendronate and albumin modulates osteoblast performance.

BACKGROUND: Biofunctionalization of titanium surfaces can improve host responses, especially considering the time for osteointegration and patient recovery. This prompted us to modify titanium surfaces with alendronate and albumin and to investigate the behavior of osteoblasts on these surfaces. METHODS: The biofunctionalization of titanium surfaces was characterized using classical physicochemical approaches and later used to challenge pre-osteoblast cells up to 24 h. Then their viability and molecular behavior were investigated using mitochondrial dehydrogenase activity and RTq-PCR technologies, respectively. Potential stimulus of extracellular remodeling was also investigated by zymography. RESULTS: Our data indicates a differential behavior of cells responding to the surfaces, considering the activity of mitochondrial dehydrogenases. Molecularly, the differential expression of genes related with cell adhesion highlighted the importance of Integrin-ß1, Fak, and Src. These 3 genes were significantly decreased in response to titanium surfaces modified with alendronate, but this behavior was reverted when alendronate was associated with albumin. Alendronate-modified surfaces promoted a significant increase on ECM remodeling, as well as culminating with greater gene activity related to the osteogenic phenotype (Runx2, Alp, Bsp). CONCLUSION: Altogether, our study found interesting osteogenic behavior of cells in response to alendronate and albumin surfaces, which indicates the need for in vivo analyses to better consider these surfaces before clinical trials within the biomedical field.