TY - JOUR A1 - Shkilnyy, Andriy A1 - Schöne, Stefanie A1 - Rumplasch, Claudia A1 - Uhlmann, Annett A1 - Hedderich, Annett A1 - Günter, Christina A1 - Taubert, Andreas T1 - Calcium phosphate mineralization with linear poly(ethylene imine) a time-resolved study JF - Colloid and polymer science : official journal of the Kolloid-Gesellschaft N2 - We have earlier shown that linear poly(ethylene imine) (LPEI) is an efficient growth modifier for calcium phosphate mineralization from aqueous solution (Shkilnyy et al., Langmuir, 2008, 24 (5), 2102). The current study addresses the growth process and the reason why LPEI is such an effective additive. To that end, the solution pH and the calcium and phosphate concentrations were monitored vs. reaction time using potentiometric, complexometric, and photometric methods. The phase transformations in the precipitates and particle morphogenesis were analyzed by X-ray diffraction and transmission electron microscopy, respectively. All measurements reveal steep decreases of the pH, calcium, and phosphate concentrations along with a rapid precipitation of brushite nanoparticles early on in the reaction. Brushite transforms into hydroxyapatite (HAP) within the first 2 h, which is much faster than what is reported, for example, for calcium phosphate precipitated with poly(acrylic acid). We propose that poly(ethylene imine) acts as a proton acceptor (weak buffer), which accelerates the transformation from brushite to HAP by taking up the protons that are released from the calcium phosphate precipitate during the phase transformation. KW - Calcium phosphate KW - Polyethylene imine KW - Mineralization KW - Kinetics Y1 - 2011 U6 - https://doi.org/10.1007/s00396-011-2403-2 SN - 0303-402X VL - 289 IS - 8 SP - 881 EP - 888 PB - Springer CY - New York ER - TY - JOUR A1 - Bleek, Katrin A1 - Taubert, Andreas T1 - New developments in polymer-controlled, bioinspired calcium phosphate mineralization from aqueous solution JF - Acta biomaterialia N2 - The polymer-controlled and bioinspired precipitation of inorganic minerals from aqueous solution at near-ambient or physiological conditions avoiding high temperatures or organic solvents is a key research area in materials science. Polymer-controlled mineralization has been studied as a model for biomineralization and for the synthesis of (bioinspired and biocompatible) hybrid materials for a virtually unlimited number of applications. Calcium phosphate mineralization is of particular interest for bone and dental repair. Numerous studies have therefore addressed the mineralization of calcium phosphate using a wide variety of low- and high-molecular-weight additives. In spite of the growing interest and increasing number of experimental and theoretical data, the mechanisms of polymer-controlled calcium phosphate mineralization are not entirely clear to date, although the field has made significant progress in the last years. A set of elegant experiments and calculations has shed light on some details of mineral formation, but it is currently not possible to preprogram a mineralization reaction to yield a desired product for a specific application. The current article therefore summarizes and discusses the influence of (macro)molecular entities such as polymers, peptides, proteins and gels on biomimetic calcium phosphate mineralization from aqueous solution. It focuses on strategies to tune the kinetics, morphologies, final dimensions and crystal phases of calcium phosphate, as well as on mechanistic considerations. KW - Calcium phosphate KW - Biomimetics KW - Mineralization KW - Polymers KW - Bioinspired Y1 - 2013 U6 - https://doi.org/10.1016/j.actbio.2012.12.027 SN - 1742-7061 SN - 1878-7568 VL - 9 IS - 5 SP - 6283 EP - 6321 PB - Elsevier CY - Oxford ER -