The structural variation of Ca-carbonate grown in the presence of mono-L-glutamic and mono-L-aspartic acid

Abstract

Over the past four decades, the interest in biomineralisation has rapidly increased, helped along by an enormous improvement in analytical instrument capabilities. The main driving forces came initially from the field of medical and biochemical research, but the extraordinary characteristics of biologically produced materials (nano-composites) have also encouraged the involvement of scientists from other disciplines, in particular material scientists, who hope that the next industrial revolution will be driven by nano-technology, either through bio-mimicking or bio-inspired new materialsThis research will focus on providing evidence to clarify an uncertainty in relation to Ca-carbonate biomineralisation. A lot is known about the effect of organic substances on the polymorph and morphology of Ca-carbonate grown in their presence, but it is not clear if only the organic template and/or soluble molecules (be they natural or synthetic) direct the growth through simple structural similarity (i.e. epitaxially) or if other phenomena are involved. The production of thick amorphous layers of Ca-carbonate and the discovery of a liquid amorphous precursor has added some uncertainty about the role of the organic component. This role will be investigated using different amino-acids and varying a number of physical and chemical factors.The influence of two amino-acids commonly found in biomineralisation systems, namely L-glutamic acid (GLU) and L-aspartic acid (ASP) on the phase, abundance and morphology of CaCO3 as a function of concentration, sequence and duration of addition, and harvesting time was investigated. Ninety-six independent samples were produced, covering a wide range of organic additive concentration, harvesting time, and reactant solution as summarized in the table below.