TY  - JOUR
A1  - Prieto, Susana
A1  - Shkilnyy, Andriy
A1  - Rumplasch, Claudia
A1  - Ribeiro, Artur
A1  - Javier Arias, F.
A1  - Carlos Rodriguez-Cabello, Jose
A1  - Taubert, Andreas
T1  - Biomimetic calcium phosphate mineralization with multifunctional elastin-like recombinamers
JF  - Biomacromolecules : an interdisciplinary journal focused at the interface of polymer science and the biological sciences
N2  - Biomimetic hybrid materials based on a polymeric and an inorganic component such as calcium phosphate are potentially useful for bone repair. The current study reports on a new approach toward biomimetic hybrid materials using a set of recombinamers (recombinant protein materials obtained from a synthetic gene) as crystallization additive for calcium phosphate. The recombinamers contain elements from elastin, an elastic structural protein, and statherin, a salivary protein. Via genetic engineering, the basic elastin sequence was modified with the SN(A)15 domain of statherin, whose interaction with calcium phosphate is well-established. These new materials retain the biocompatibility, "smart" nature, and desired mechanical behavior of the elastin-like recombinamer (ELR) family. Mineralization in simulated body fluid (SBF) in the presence of these recombinamers reveals surprising differences. Two of the polymers inhibit calcium phosphate deposition (although they contain the statherin segment). In contrast, the third polymer, which has a triblock structure, efficiently controls the calcium phosphate formation, yielding spherical hydroxyapatite (HAP) nanoparticles with diameters from 1 to 3 nm after 1 week in SBF at 37 degrees C. However, at lower temperatures, no precipitation is observed with any of the polymers. The data thus suggest that the molecular design of ELRs containing statherin segments and the selection of an appropriate polymer structure are key parameters to obtain functional materials for the development of intelligent systems for hard tissue engineering and subsequent in vivo applications.
Y1  - 2011
U6  - https://doi.org/10.1021/bm200287c
SN  - 1525-7797
VL  - 12
IS  - 5
SP  - 1480
EP  - 1486
PB  - American Chemical Society
CY  - Washington
ER  - 
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  -