Modified amelogenin is a new and versatile nanomaterial for biomedical applications

Abstract

Amelogenin self-assembly is crucial for tooth biomineralization and crystallite enamel orientation. Amelogenin forms stable nanoparticles under physiological conditions. Here, we tested whether the surface properties and binding characteristics of these particles could be modified to enhance amelogenin function as a biomaterial. We evaluated different amelogenin fusion proteins for their ability to form hybrid nanoparticles. As a proof-of-concept, the integrin-binding tripeptide Arg-Gly-Asp (RGD) sequence from fibronectin was integrated into mouse amelogenin (rM179) at three different positions. Dynamic light scattering (DLS) measurements revealed that these amelogenin fusion proteins still form nanospheres. Additional DLS and isothermal titration calorimetry measurements showed that the mixtures of RGD-modified amelogenin and wild-type amelogenin form stable particles. We determined that insertion of the RGD-loop at the amelogenin C-terminus converts the nanoparticle into a cell-binding substrate. Calvarial osteoblasts efficiently attached and spread on modified amelogenin, whereas almost no binding was observed on wild-type amelogenin. These results establish amelogenin as a new versatile biomaterial that can be easily modified to add additional functions.

Functionalization of Recombinant Amelogenin Nanospheres Allows Their Binding to Cellulose Materials

“…This makes it possible to produce modified amelogenins in a simple manner, which can be assembled to nanosized aggregates. This has also recently been shown by others . Besides amelogenin fusion proteins, we have also reported that a random mutation amelogenin library can be used to create amelogenins with distinct solubility behavior, further demonstrating the possibilities to engineer the properties of this protein.…”

“…). Previous studies have shown that different amelogenin variants can be mixed at non‐aggregating conditions and co‐assembled into composite amelogenin aggregates with distinct properties that depend on the proportion of the individual amelogenin variants . In the present study we observed a difference in solubility when rh174CBD and rh174 were mixed (Fig.…”

“…The ability of amelogenin to self‐assemble into nanosized aggregates makes it an important protein to explore as a building block for nanomaterials . Previously we have described a method for producing recombinant amelogenin that enables simple production of large quantities of the protein .…”

TGF-β1 autocrine signalling and enamel matrix components

“…These findings suggest that TGF-β1 in the secretory-stage enamel binds to the P173, P162, P148 and P103 amelogenins. The full-length amelogenin is a complex molecule consisting of four functional domains: TRAP, Coil, a PXX repeat and a hydrophilic C-terminal domain 35 36 (see Supplementary Fig. S11 ).…”

“…DLS analysis has been used to investigate the mechanisms of amelogenin-cell interactions during amelogenesis 36 44 . Porcine secretory-stage enamel contains 50% water, 25% minerals and 25% proteins, although those ratios are different in the outer, outer-inner and inner layers 40 .…”