skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Polyaspartic Acid Concentration Controls the Rate of Calcium Phosphate Nanorod Formation in High Concentration Systems

Abstract

Polyelectrolytes are known to greatly affect calcium phosphate (CaP) mineralization. The reaction kinetics as well as the CaP phase, morphology and aggregation state depend on the relative concentrations of the polyelectrolyte and the inorganic ions in a complex, nonlinear manner. This study examines the structural evolution and kinetics of polyaspartic acid (pAsp) directed CaP mineralization at high concentrations of polyelectrolytes, calcium, and total phosphate (19–30 mg/mL pAsp, 50–100 mM Ca2+, Ca/P = 2). Using a novel combination of characterization techniques including cryogenic transmission electron microscopy (cryo-TEM), spectrophotometry, X-ray total scattering pair distribution function analysis, and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), it was determined that the CaP mineralization occurred over four transition steps. The steps include the formation of aggregates of pAsp stabilized CaP spherical nanoparticles (sNP), crystallization of sNP, oriented attachment of the sNP into nanorods, and further crystallization of the nanorods. The intermediate aggregate sizes and the reaction kinetics were found to be highly polymer concentration dependent while the sizes of the particles were not concentration dependent. This study demonstrates the complex role of pAsp in controlling the mechanism as well as the kinetics of CaP mineralization.

Authors:
ORCiD logo [1];  [1];  [1]
  1. Biosystems and Biomaterials Division, National Institute of Standards and Technology, Gaithersburg, Maryland, United States
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
OTHERNIST
OSTI Identifier:
1408130
Resource Type:
Journal Article
Journal Name:
Biomacromolecules
Additional Journal Information:
Journal Volume: 18; Journal Issue: 10; Journal ID: ISSN 1525-7797
Publisher:
American Chemical Society
Country of Publication:
United States
Language:
ENGLISH
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Krogstad, Daniel V., Wang, Dongbo, and Lin-Gibson, Sheng. Polyaspartic Acid Concentration Controls the Rate of Calcium Phosphate Nanorod Formation in High Concentration Systems. United States: N. p., 2017. Web. doi:10.1021/acs.biomac.7b00772.
Krogstad, Daniel V., Wang, Dongbo, & Lin-Gibson, Sheng. Polyaspartic Acid Concentration Controls the Rate of Calcium Phosphate Nanorod Formation in High Concentration Systems. United States. doi:10.1021/acs.biomac.7b00772.
Krogstad, Daniel V., Wang, Dongbo, and Lin-Gibson, Sheng. Thu . "Polyaspartic Acid Concentration Controls the Rate of Calcium Phosphate Nanorod Formation in High Concentration Systems". United States. doi:10.1021/acs.biomac.7b00772.
@article{osti_1408130,
title = {Polyaspartic Acid Concentration Controls the Rate of Calcium Phosphate Nanorod Formation in High Concentration Systems},
author = {Krogstad, Daniel V. and Wang, Dongbo and Lin-Gibson, Sheng},
abstractNote = {Polyelectrolytes are known to greatly affect calcium phosphate (CaP) mineralization. The reaction kinetics as well as the CaP phase, morphology and aggregation state depend on the relative concentrations of the polyelectrolyte and the inorganic ions in a complex, nonlinear manner. This study examines the structural evolution and kinetics of polyaspartic acid (pAsp) directed CaP mineralization at high concentrations of polyelectrolytes, calcium, and total phosphate (19–30 mg/mL pAsp, 50–100 mM Ca2+, Ca/P = 2). Using a novel combination of characterization techniques including cryogenic transmission electron microscopy (cryo-TEM), spectrophotometry, X-ray total scattering pair distribution function analysis, and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), it was determined that the CaP mineralization occurred over four transition steps. The steps include the formation of aggregates of pAsp stabilized CaP spherical nanoparticles (sNP), crystallization of sNP, oriented attachment of the sNP into nanorods, and further crystallization of the nanorods. The intermediate aggregate sizes and the reaction kinetics were found to be highly polymer concentration dependent while the sizes of the particles were not concentration dependent. This study demonstrates the complex role of pAsp in controlling the mechanism as well as the kinetics of CaP mineralization.},
doi = {10.1021/acs.biomac.7b00772},
journal = {Biomacromolecules},
issn = {1525-7797},
number = 10,
volume = 18,
place = {United States},
year = {2017},
month = {8}
}