Biomedical implants have shown great promise as bone tissue replacement in recent decades. In addition to mechanical properties, biocompatibility and the prevention of infections are crucial for a long lifetime of an implant. To enhance implant biointegration and healing process, bioactive ceramic coatings have been developed in recent years. Especially calcium phosphate (CaP) has received great attention due to its similarity to the mineral phase of natural bone. Besides CaP, magnesium phosphate (MgP) is also of interest due to its outstanding solubility.[1] Biodegradation as well as high cell adhesion are quite important features and depend on the porosity of the surface. However, the influence of porosity of the coating is not fully understood yet. An increase of porosity can be achieved by using nanoparticles (NPs). In particular, CaP and MgP NPs offer a number of advantages with regard to biomedical applications such as high biocompatibility and osteoconductivity.

Here, we present our recent activities in the research field of the synthesis and characterization of CaP and MgP raspberry-like microparticles for the coating of bone implants. CaP and MgP NPs were prepared by a sol−gel process.[2] Different Ca and Mg to P ratios of the precursors were tested during synthesis followed by annealing of the NPs at high temperatures to obtain crystalline phases. In the second step, NPs were processed to micro-raspberry particles by the spray drying method (Figure 1).[3] To obtain an antibacterial effect, Cu ions were introduced in the process.The characterization of the resulting particles was done by dynamic light scattering (DLS), scanning and transmission electron microscopy (SEM, TEM), zeta potential, inductively coupled plasma mass spectrometry (ICP-MS), the Brunauer-Emmett-Teller (BET) method and x-ray diffraction analysis (XRD).

References

[1] A. Fuchs, D. Kreczy, T. Brückner, U. Gbureck, P. Stahlhut, M. Bengel, A. Hoess, B. Nies, J. Bator, U. Klammert, et al., Clinical oral investigations 2021.

[2] C. von Schirnding, I. Giopanou, A. Hermawan, L. Wehl, G. Ntaliarda, B. Illes, S. Datz, F. Geisslinger, K. Bartel, A.-K. Sommer, et al., Chem 2021, 7, 480.

[3] C. Stauch, T. Ballweg, W. Stracke, R. Luxenhofer, K. Mandel, Journal of Colloid and Interface Science 2017, 490, 401.