Bone regeneration is an important step in various reconstruction processes, such as orthopedic and dental treatment. However, the long time (i.e., 3 months) and costs required makes bone regeneration difficult to be applied widely. Therefore, efficient and low cost materials are on demand, especially in the current super-aging society. 

Phospholipids, which are the natural biological molecules that form cell membranes, are available at large amounts. These molecules have a hydrophilic head and a hydrophobic tail linked to a central phosphate group. The hydrophobic tail are always composed of aliphatic carbon chains, while the hydrophilic head can be of different types: if the head is choline, the phospholipid is phosphatidylcholine (PC), and if the head is serine then phosphatidylserine (PS) results. Phospholipids were shown to be the nucleus of mineralization into materials like hydroxyapatites (made of phosphate, calcium and water), which can be used in artificial bones. Each type of phospholipid (PC and PS, for example) was found to mineralize with different efficiencies, but the mechanism through which such mineralization occurs is still unclear.

In this work, we investigated the mineralization of PC and PS experimentally and computationally, in order to elucidate their mineralization mechanisms. By combining, the experimental and the computational results, we found that hydrolysis is the first step in the mineralization process. In addition, the hydrolysis reactions of PC and of PS were found to proceed through elementary reactions that differed in activation energies and reaction dynamics, depending on the reactivities of the hydrophilic head of the phospholipid. Proton transfer reactions were identified as a crucial step in the hydrolysis of phospholipids, and these were the reactions that occurred through different dynamics depending on the type of phospholipid.