Bio-Inspired Hydrogel-Calcium Carbonate Core-Shell Particles
- PDF / 958,286 Bytes
- 7 Pages / 612 x 792 pts (letter) Page_size
- 28 Downloads / 209 Views
0988-QQ03-04
Bio-Inspired Hydrogel-Calcium Carbonate Core-Shell Particles Yi-Yeoun Kim1, John W. Catino2, Gary P. Tomaino2, and Sherman D. Cox1 1 Strategic Research & Discovery, Specialty Minerals Inc, 9 Highland Ave, Bethlehem, PA, 18017 2 Analytical Services, Specialty Minerals Inc, 640 N. 13th Street, Easton, PA, 18042
ABSTRACT In this report, we present a bio-inspired encapsulation process to create nanoclusterassembled core-shell particles under aqueous, room temperature and non-toxic conditions. The approach to synthesize calcium carbonate core-shell particles is accomplished by employing a Polymer-Induced Liquid-Precursor (PILP) process. We demonstrate the amorphous mineral precursor is coated around a core of hydrogel nanoparticles, and subsequently solidified and crystallized. the synthesized core-shell particles are 300~500nm diameter and ~100 nm shellthickness. We investigate the role of the hydrogel core of the particle using time-resolved XRD, thermal-XRD and thermal analysis. The organic hydrogel appears to influence the transformation of mineral phases, stabilizing the amorphous phase of calcium carbonate. INTRODUCTION This report demonstrates an approach to synthesize core-shell particles with a chemical system composed of a hydrogel core and a calcium carbonate shell, using a biomimetic crystallization process called the PILP (Polymer-Induced Liquid Precursor) process. The submicron size core-shell particles are created by an assembly of mineral-nanoclusters around the hydrogel nanoparticles. Increasing attention over core-shell particles for various uses such as controlled drug delivery and protection of fragile, often biological species has lead to extensive studies on this topic using various processes and materials.1-3 A typically applied method for the core-shell particle is coating the surface of a core, followed by removing the interior core by chemical etching or calcinations. It is thus often called a sacrificial template. A similar strategy via the PILP process for core-shell particles has been reported using an emulsion micro-droplet as a core and calcium carbonate as a shell. 4 In this study, a hydrogel nanoparticle core was chosen as a template for calcium carbonate to deposit on. The calcium carbonate/hydrogel system is closely connected to the in vivo system of nacre formation. This can provide an insight to understand the unusual formation and structures of biominerals, such as the coexistence of ACC (amorphous calcium carbonate) and crystalline phases with complex morphology. Thus, one of our interests in this study is the influence of an organic template core on stabilizing amorphous phase.
EXPERIMENTAL DETAILS Hydrogel nanoparticles were used as an organic core template. The diameter of hydrogel nanoparticles is around 200 nm by DLS and confocal optical microscopy (data not presented here). The PILP crystallization process is as follows: a 24 mM CaCl2•2H2O and 42 mM MgCl2•6H2O mixed solution was prepared with deionized water. Micromolar quantities of dissolved acidic polymer (
Data Loading...
