Collaboration Fund

A novel hypothesis of biomineralisation proposes that pre-nucleation clusters aggregate to amorphous nano-particles that are then directed into crystallographic order by proteins, which adsorb onto their surface.  Biominerals display remarkable properties, a fact attributed to their composite structures.  Even single crystal biominerals such as sea urchin spines contain protein molecules embedded within each crystal – which vastly improves their mechanical properties.

This hypothesis links recent observations of pre-nucleation clusters, amorphous carbonate phases at the onset of mineralization (Meldrum), the presence of nano-voids (Kröger) and a suite of entrapped proteins within biominerals. We speculated that the entrapped intra-crystalline proteins (Penkman, Collins) are those observed to direct clusters towards crystalline CaCO3 formation.  We believe that we have unlocked the key to this model by computational modelling of an intra-crystalline chicken eggshell protein (Harding) where basic amino acids punch through the structured water layer surrounding amorphous clusters and direct them to re-arrange into calcite.

We now intend to carry out preliminary experiments to investigate the validity of this hypothesis. Model biomolecules will be designed by Collins & Penkman. Meldrum and Kim will perform crystal growth experiments and characterisation to investigate the effects of these molecules on calcium carbonate crystal growth. Kröger will investigate how the biomolecules are incorporated into crystals using high-resolution transmission electron microscopy. Harding and Freeman will perform molecular dynamics simulations to investigate how the molecules adsorb onto surfaces and are incorporated within calcite crystals