title: Urease-induced calcification of segmented polymer hydrogels - a step towards artificial biomineralization.
abstract: Natural organic/inorganic composites, such as nacre, bones and teeth, are perfectly designed materials with exceptional mechanical properties. Numerous approaches have been taken to synthetically prepare such composites. The presented work describes a new way of mineralizing bulk materials on a large scale following the approach of bioinduced mineralization. To this end, a series of polymer conetworks with entrapped urease were prepared. After polymerization, the entrapped urease shows high enzymatic activity. The bioactive polymer conetworks were then treated with an aqueous mixture of urea and CaCl2. The urease-induced calcification indeed allows formation of carbonate crystals exclusively within the hydrogel even at room temperature. The influence of network composition, degree of cross-linking, immobilized urease concentration and temperature of calcification were investigated. By varying these parameters, spherical, monolithic clusters, as well as bar-like nanocrystals with different aspect ratios in spherical or dendritic arrays, are formed. The grown nanocrystals improve the stiffness of the starting material by up to 700-fold, provided that the microstructure shows a dense construction without pores and strong interaction between crystals and network. The process has the potential to generate a new class of hybrid materials that would be available on the macroscopic scale for use in lightweight design and medicine.
authors.affiliation: TU Dortmund, Emil-Figge-Str. 66, 44227 Dortmund, Germany.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Rauner
authors.affiliation: TU Dortmund, Emil-Figge-Str. 66, 44227 Dortmund, Germany.
authors.forename: Monika
authors.initials: M
authors.lastname: Meuris
authors.affiliation: TU Dortmund, Emil-Figge-Str. 66, 44227 Dortmund, Germany.
authors.forename: Stephan
authors.initials: S
authors.lastname: Dech
authors.affiliation: TU Dortmund, Emil-Figge-Str. 66, 44227 Dortmund, Germany.
authors.forename: Julia
authors.initials: J
authors.lastname: Godde
authors.affiliation: TU Dortmund, Emil-Figge-Str. 66, 44227 Dortmund, Germany. Electronic address: tiller@tu-dortmund.de.
authors.forename: Joerg C
authors.initials: JC
authors.lastname: Tiller
mesh_terms: D000179:Acrylates / Q000737:chemistry*; D002113:Calcification, Physiologic / Q000187:drug effects*; D002119:Calcium Carbonate / Q000737:chemistry*; D032449:Canavalia / Q000201:enzymology; D003432:Cross-Linking Reagents / Q000494:pharmacology; D003460:Crystallization; D055119:Elastic Modulus / Q000187:drug effects; D004800:Enzymes, Immobilized / Q000494:pharmacology; D020100:Hydrogels / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D011092:Polyethylene Glycols / Q000737:chemistry; D011108:Polymers / Q000737:chemistry*; D011109:Polymethacrylic Acids / Q000737:chemistry; D013696:Temperature; D014510:Urease / Q000494:pharmacology*
chemical_list: D000179:Acrylates; D003432:Cross-Linking Reagents; D004800:Enzymes, Immobilized; D020100:Hydrogels; D011108:Polymers; D011109:Polymethacrylic Acids; C020946:triethylene glycol dimethacrylate; C035957:2-hydroxyethyl acrylate; D011092:Polyethylene Glycols; D014510:Urease; D002119:Calcium Carbonate
keywords: Artificial biomineralization; Hydrogel; Organic/inorganic hybrid materials; Polymer conetwork; Urease-induced calcification