Polysaccharide chemistry regulates kinetics of calcite nucleation through competition of interfacial energies
Polysaccharide chemistry regulates kinetics of calcite nucleation through competition of interfacial energies
复制标题
DOI：
10.1073/pnas.1222162110
复制
发表时间：
2013-06-04
影响因子：
11.1
通讯作者：
Dove, Patricia M.
中科院分区：
文献类型：
--
作者：
Giuffre, Anthony J.;Hamm, Laura M.;Dove, Patricia M.
钙化骨骼是在蛋白质和多糖的复杂组合中产生的，其在矿化中的作用尚不清楚。在这里，我们量化了在受控条件下方解石在一组高纯度多糖(PS)底物上成核的动力学。成核的能垒是PS特有的，它与PS电荷密度和衬底结构的系统关系源于竞争衬底-晶体和衬底-液体界面能的最小化。壳聚糖是一种低能成核屏障，因为其近中性的电荷有利于形成基质-晶体界面，从而减少了基质与水的相互作用。对于带负电荷的海藻酸盐和肝素，测量到的势垒越高，越有利于与溶液接触形成新的基质-晶体界面。这些发现支持PS在生物矿物形成中的指导作用，并表明基质-晶体相互作用是调节异质晶体成核的更大竞争力量连续体中的一个终端成员。
Calcified skeletons are produced within complex assemblages of proteins and polysaccharides whose roles in mineralization are not well understood. Here we quantify the kinetics of calcite nucleation onto a suite of high-purity polysaccharide (PS) substrates under controlled conditions. The energy barriers to nucleation are PS-specific by a systematic relationship to PS charge density and substrate structure that is rooted in minimization of the competing substrate-crystal and substrate-liquid interfacial energies. Chitosan presents a low-energy barrier to nucleation because its near-neutral charge favors formation of a substrate-crystal interface, thus reducing substrate interactions with water. Progressively higher barriers are measured for negatively charged alginates and heparin that favor contact with the solution over the formation of new substrate-crystal interfaces. The findings support a directing role for PS in biomineral formation and demonstrate that substrate-crystal interactions are one end-member in a larger continuum of competing forces that regulate heterogeneous crystal nucleation.