1.Photosynthetic biomineralization of radioactive Sr via microalgal CO2 absorption.
Lee SY1, Jung KH2, Lee JE3, Lee KA4, Lee SH5, Lee JY6, Lee JK6, Jeong JT6, Lee SY7. Bioresour Technol. 2014 Nov;172:449-52. doi: 10.1016/j.biortech.2014.09.023. Epub 2014 Sep 16.
Water-soluble radiostrontium ((90)Sr) was efficiently removed as a carbonate form through microalgal photosynthetic process. The immobilization of soluble (90)Sr radionuclide and production of highly-precipitable radio-strontianite ((90)SrCO3) biomineral are achieved by using Chlorella vulgaris, and the biologically induced mineralization drastically decreased the (90)Sr radioactivity in water to make the highest (90)Sr removal ever reported. The high-resolution microscopy revealed that the short-term removal of soluble (90)Sr by C. vulgaris was attributable to the rapid and selective carbonation of (90)Sr together with the consumption of dissolved CO2 during photosynthesis. A small amount of carbonate in water could act as Sr(2+) sinks through the particular ability of the microalga to make the carbonate mineral of Sr stabilized firmly at the surface site.
2.Interfacial Reaction-Driven Formation of Silica Carbonate Biomorphs with Subcellular Topographical Features and Their Biological Activity.
Wang G1, Zhao X2, Möller M, Moya SE. ACS Appl Mater Interfaces. 2015 Oct 28;7(42):23412-7. doi: 10.1021/acsami.5b08493. Epub 2015 Oct 13.
We report the interfacial reaction-driven formation of micro/nanostructured strontium carbonate (SrCO3) biomorphs with subcellular topographical features on strontium zinc silicate (Sr2ZnSi2O7) biomedical coatings and explore their potential use in bone tissue engineering. The resulting SrCO3 crystals build a well-integrated scaffold surface that not only prevents burst release of ions from the coating but also presents nanotopographical features similar to cellular filopodia. The surface with biomorphic crystals enhances osteoblast adhesion, upregulates the alkaline phosphatase activity, and increases collagen production, highlighting the potential of the silica carbonate biomorphs for tissue regeneration.
3.A novel and easy-to-prepare strontium(II) modified calcium phosphate bone cement with enhanced mechanical properties.
Schumacher M1, Henß A, Rohnke M, Gelinsky M. Acta Biomater. 2013 Jul;9(7):7536-44. doi: 10.1016/j.actbio.2013.03.014. Epub 2013 Mar 20.
The aim of this study was to evaluate two different approaches to obtaining strontium-modified calcium phosphate bone cements (SrCPCs) without elaborate synthesis of Sr-containing calcium phosphate species as cement precursors that could release biologically effective doses of Sr(2+) and thus could improve the healing of osteoporotic bone defects. Using strontium carbonate as a strontium(II) source, it was introduced into a hydroxyapatite-forming cement either by the addition of SrCO3 to an α-tricalcium phosphate-based cement precursor mixture (A-type) or by substitution of CaCO3 by SrCO3 during precursor composition (S-type). The cements, obtained after setting in a water-saturated atmosphere, contained up to 2.2at.% strontium in different distribution patterns as determined by time-of-flight secondary ion mass spectrometry and energy-dispersive X-ray spectroscopy. The setting time of CPC and A-type cements was in the range of 6.5-7.5min and increased for substitution-type cements (12.
4.Controlling nucleation in giant liposomes.
Tester CC1, Whittaker ML, Joester D. Chem Commun (Camb). 2014 May 30;50(42):5619-22. doi: 10.1039/c4cc01457j.
We introduce giant liposomes to investigate phase transformations in picoliter volumes. Precipitation of calcium carbonate in the confinement of DPPC liposomes leads to dramatic stabilization of amorphous calcium carbonate (ACC). In contrast, amorphous strontium carbonate (ASC) is a transient species, and BaCO3 precipitation leads directly to the formation of crystalline witherite.