Experimental calcification of HEMA-based hydrogels in the presence of albumin and a comparison to the in vivo calcification.
The precipitation patterns and characteristics of calcium phosphate (CaP) phases deposited on HEMA-based hydrogels upon incubation in simulated body fluid (SBF-2) containing a protein (human serum albumin) have been investigated in relation to the calcification in an organic-free medium (SBF-1) and to that occurring after subcutaneous implantation in rats. In SBF-2, the deposits occurred exclusively as a peripheral layer on the surface of the hydrogels and consisted mainly of "precipitated hydroxyapatite", a species deficient in calcium and hydroxyl ions, similarly to the deposits formed on the implanted hydrogels, where the deposited layer was thicker. In SBF-1, the deposits were mainly of brushite type. There was no evidence that albumin penetrated the interstices of hydrogels. As the X-ray diffraction patterns of the CaP deposits generated in SBF-2 showed a similar nature with those formed on the implanted hydrogel, it was concluded that the calcification in SBF-2 can mimic to a reliable extent the calcification process taking place in a biological environment.
Zainuddin
Zainuddin
Z
Department of Chemistry, University of Queensland, Santa Lucia, Brisbane, Queensland 4072, Australia.
Hill
David J T
DJ
Chirila
Traian V
TV
Whittaker
Andrew K
AK
Kemp
Anne
A
D000818:Animals; D002113:Calcification, Physiologic; D002130:Calcium Phosphates / Q000737:chemistry; D005260:Female; D006801:Humans; D020100:Hydrogels / Q000008:administration & dosage / Q000138:chemical synthesis / Q000737:chemistry*; D007279:Injections, Subcutaneous; D047908:Intracellular Signaling Peptides and Proteins / Q000737:chemistry / Q000502:physiology; D008689:Methacrylates / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D017027:Protein Tyrosine Phosphatases / Q000737:chemistry / Q000502:physiology; D054558:Protein Tyrosine Phosphatases, Non-Receptor; D051381:Rats; D017208:Rats, Wistar; D012542:Scattering, Radiation; D012709:Serum Albumin / Q000737:chemistry*; D013499:Surface Properties; D014965:X-Rays
D002130:Calcium Phosphates; D020100:Hydrogels; D047908:Intracellular Signaling Peptides and Proteins; D008689:Methacrylates; C111446:SBF1 protein, human; D012709:Serum Albumin; C005044:hydroxyethyl methacrylate; C020243:calcium phosphate; D017027:Protein Tyrosine Phosphatases; D054558:Protein Tyrosine Phosphatases, Non-Receptor; C475072:SBF2 protein, human