Poly(ethylene imine)-Controlled Calcium Phosphate Mineralization

Abstract

The current paper shows that poly(ethylene imine) (PEI) is an efficient template for the fabrication of spherical calcium phosphate (CaP)/polymer hybrid particles at pH values above 8. The polymer forms spherical entities, which contain one or a few CaP particles with diameters of ca. 6 nm. The samples contain up to 20 wt % polymer, which appears to be wrapped around the small CaP particles. The particles form via a mineralization-trapping pathway, where at the beginning of the precipitation small CaP particles form. Further particle growth is then prevented by precipitation of the PEI onto these particles at pH values of ca. 8. Stabilization of the particles is provided by the re-protonation of the PEI, which is adsorbed on the CaP particles, during the remainder of the mineralization process. At low pH, much larger particles form. They most likely grow via heterogeneous nucleation and growth on existing, polymermodified CaP surfaces.

Crystal structure and chemical composition of biomimetic calcium phosphate nanofibers

“…Previous data on polycation-mediated calcium phosphate mineralization 13,14,21 indeed indicate that polymer-ion association may be the key step in the mineralization process (this is also supported by new data on calcium carbonate 36 and CuO x mineralization 37 ).…”

Hydroxylapatite nanoparticles: fabrication methods and medical applications

“…The morphology of HAp nanoparticles also depends on additives, such as surfactant molecules [104,105] (cf micelle-templated method described in the next paragraph, and emulsion methods described in section 2.2.5), alcohol [106], amino acids [107][108][109], citrates [110,111], poly(acrylic acid) [112,113], poly(ethylene imine) [114,115], poly(ethylene oxide) (poly(ethylene glycol)) [116,117], poly(vinyl alcohol) [118,119] and biopolymers [119], mainly due to the inhibition of crystal growth by preferentially adsorbing the additives onto a HAp surface (a or c plane).…”

Polymer‐Controlled, Bio‐Inspired Calcium Phosphate Mineralization from Aqueous Solution

“…[80] The acids coordinate to Ca 2þ and HAP precipitates through a dissolution-precipitation process under mild basic conditions. Prelot and Zemb have reported the formation of mesoporous HAP from poly(ethylene oxide) oleyl phosphate [81] and our group has recently fabricated CaP hybrid nanoparticles using poly(ethylene imine) as a growth modifier, [82] Figure 1.…”