Functionalized-ferroelectric-coating-driven enhanced biomineralization and protein-conformation on metallic implants.

In the context of bone regeneration, it is important to have platforms that with appropriate stimuli can support the attachment and direct the growth, proliferation and differentiation of cells. In the orthopedic field, metals and alloys are still the dominant materials used as implants, though their bioinert character leads to failure or to the need for multiple revision procedures. To respond to this situation here we exploit an alternative strategy for bone implants or repairs, based on charge mediating signals for bone regeneration, envisaged as a type of biological micro-electromechanical system (BioMEM).

Pairing High Piezoelectric Coefficients, d, with High Curie Temperature (T) in Lead-Free (K,Na)NbO.

The largest piezoelectric properties, d = 416 pC/N and 490 pC/N, in KNaNbO ceramics have been reported for compositions close to polymorphic phase transition (PPT); however, they also have Curie temperatures, T, of around 217-304 °C, considerably lower than those of undoped KNN ceramics (420 °C). High d along with high T remains the ideal choice for applications but, unfortunately, not attained up to now. Here, we show that using KNN single crystals as seeds for template grain growth (TGG) of KNN ceramics enables dramatic improvements in the electromechanical properties while maintaining a high T.

Are lithium niobate (LiNbO3) and lithium tantalate (LiTaO3) ferroelectrics bioactive?

The use of functional materials, such as ferroelectrics, as platforms for tissue growth in situ or ex situ, is new and holds great promise. But the usage of materials in any bioapplication requires information on biocompatibility and desirably on bioactive behavior when bone tissue engineering is envisaged. Both requirements are currently unknown for many ferroelectrics.