Enzymatic pH control for biomimetic deposition of calcium phosphate coatings

Arnold W.G. Nijhuis, M. Reza Nejadnik, Fabio Nudelman, X. Frank Walboomers, Joost te Riet, Pamela Habibovic, Zeinab Tahmasebi Birgani, Li Yubao, Paul H.H. Bomans, John A. Jansen, Nico A.J.M. Sommerdijk, Sander C.G. Leeuwenburgh

Research output: Contribution to journalArticleAcademicpeer-review

15 Citations (Scopus)

Abstract

The current study has focused on enzymatic decomposition of urea into carbon dioxide and ammonia as a means to increase the pH during biomimetic deposition of Calcium Phospate (CaP) onto implant surfaces. The kinetics of the enzymatically induced pH increase were studied by monitoring pH, calcium concentration and conductivity of the aqueous solutions as a function of time, urease concentration and initial concentrations of calcium and phosphate ions. Cryogenic Transmission Electron Microscopy (CryoTEM) was used to study the process of homogeneous CaP precipitation in solution, whereas CaP deposition on conventional acid-etched Titanium (Ti) and micropatterned polystyrene (PS) surfaces was studied using Scanning Electron Microscopy (SEM). The data presented in this study confirm that the substrate-enzyme combination urea-urease offers strong control over the rate of pH increase by varying the concentrations of precursor salts and urease. Formation of biomimetic CaP coatings was shown to proceed via formation of ionic polymeric assemblies of prenucleation complexes. The process of deposition and corresponding coating morphology was strongly dependent on the concentration of calcium, phosphate and urease. Finally, it was shown that the substrate-enzyme combination urea-urease allowed for spatial distribution of CaP crystals along the grooves of micropatterned PS surfaces at low concentrations of calcium, phosphate and urease, stressing the sensitivity of the presented method.
Original languageEnglish
Pages (from-to)931-939
Number of pages37
JournalActa biomaterialia
Volume10
Issue number2
DOIs
Publication statusPublished - 3 Oct 2014

Keywords

  • Calcification
  • Pre-nucleation clusters
  • Patterned surfaces
  • Hydroxyapatite
  • Calcium phosphate coating

Fingerprint Dive into the research topics of 'Enzymatic pH control for biomimetic deposition of calcium phosphate coatings'. Together they form a unique fingerprint.

Cite this