title: Mechanism of formation of concentrically laminated spherules: implication to Randall's plaque and stone formation.
abstract: We report on the formation of calcium phosphate multi-laminated spherules via a polymer-induced liquid-like precursor (PILP) process. In this non-classical crystallization route, the precipitation of liquid-like amorphous calcium phosphate (ACP) particles is promoted using anionic polypeptide additives, and these droplets coalesce to form globules that later crystallize into spherulites. During crystallization of the amorphous globules, the polymer additive, as well as the waters of hydration, is excluded ahead of the crystallization front, but some polymer becomes entrapped within diffusion-limited zones. This results in the formation of concentric laminations with layers of variable density from organic-rich inclusions. The striking resemblance of these spherules with the crystals of the Randall's plaque and other laminated stones suggests that such biological structures may form via an amorphous precursor process as well. Given the organic-rich environment present in the urinary tract, one might expect a large amount of organic materials to become entrapped within the stratified zones of a forming stone during this type of solidification and transformation process.
authors.affiliation: Department of Materials Science and Engineering, University of Florida, Gainesville, FL 32611, USA.
authors.forename: Fairland F
authors.initials: FF
authors.lastname: Amos
authors.forename: Lijun
authors.initials: L
authors.lastname: Dai
authors.forename: Rajendra
authors.initials: R
authors.lastname: Kumar
authors.forename: Saeed R
authors.initials: SR
authors.lastname: Khan
authors.forename: Laurie B
authors.initials: LB
authors.lastname: Gower
mesh_terms: D000818:Animals; D002130:Calcium Phosphates / Q000737:chemistry*; D002137:Calculi / Q000737:chemistry / Q000209:etiology*; D011232:Chemical Precipitation; D003460:Crystallization; D018360:Crystallography, X-Ray; D006801:Humans; D066298:In Vitro Techniques; D007669:Kidney Calculi / Q000737:chemistry / Q000209:etiology; D008855:Microscopy, Electron, Scanning; D008903:Minerals / Q000737:chemistry; D008954:Models, Biological; D010316:Particle Size; D010455:Peptides / Q000737:chemistry; D011108:Polymers
chemical_list: D002130:Calcium Phosphates; D008903:Minerals; D010455:Peptides; D011108:Polymers; C020243:calcium phosphate