Comparative In Vitro Osteoinductivity Study of CaP Ceramics (HA, α-TCP, β-TCP) using 10T1/2 Cells with Different Controls and Possible Correlations with Other Systems

In this study, we use a pluripotent mesenchymal stem cell (MSC) model, C3H/10T1/2, to evaluate three calcium phos-phate (CaP) materials, namely the hydroxyapatite (HA), α-tricalcium phosphate (α-TCP) and β-tricalcium phosphate (β-TCP). 10T1/2 cell was chosen as it has advantages over its counterparts in terms of ease of maintenance, free of ethical concerns and also more reproducible results. ALP enzymatic assay, RT-qPCR, DAPI staining and SEM were employed to assess the osteoinductivity of these materials. A good reference material which also acts as a scientific control is necessary for comparisons of results from different experimental batches and hence other materials such as titanium, Nunclon plastic surface, BD Falcon plastic surface and gold coated porous HA were also tested. The results show that ceramics induce a more sustained osteo-differentiation state as compared with plastics. Inductivity was found to be acting in descending order of strength with HA > β-TCP > α-TCP, which is reversed in terms of their impact on proliferation rate (HA TCP) and in vivo osteoinductivity in terms of incidence and quality of bone described previously (HA > β-TCP > α-TCP). These confirm the suitability of using 10T1/2 cells in cell culture assay of osteoinductivity.

Rational integration of defense and repair synergy on PEEK osteoimplants via biomimetic peptide clicking strategy

Polyetheretherketone(PEEK)has been widely used as orthopedic and dental materials due to excellent mechanical and physicochemical tolerance.However,its biological inertness,poor osteoinduction,and weak antibacterial activity make the clinical applications in a dilemma.Inspired by the mussel adhesion mechanism,here we reported a biomimetic surface strategy for rational integration and optimization of anti-infectivity and osteo-inductivity onto PEEK surfaces using a mussel foot proteins(Mfps)-mimic peptide with clickable azido terminal.The peptide enables mussel-like adhesion on PEEK biomaterial surfaces,leaving azido groups for the further steps of biofunctionalizations.In this study,antimicrobial peptide(AMP)and osteogenic growth peptide(OGP)were bioorthogonally clicked on the azido-modified PEEK biomaterials to obtain a dual-effect of host defense and tissue repair.Since bioorthogonal clicking allows precise collocation between AMP and OGP through changing their feeding molar ratios,an optimal PEEK surface was finally obtained in this research,which could long-term inhibit bacterial growth,stabilize bone homeostasis and facilitate interfacial bone regeneration.In a word,this upgraded mussel surface strategy proposed in this study is promising for the surface bioengineering of inert medical implants,in particular,achieving rational integration of multiple biofunctions to match clinical requirements.