Limits...
3D visualization of additive occlusion and tunable full-spectrum fluorescence in calcite

View Article: PubMed Central - PubMed

ABSTRACT

From biomineralization to synthesis, organic additives provide an effective means of controlling crystallization processes. There is growing evidence that these additives are often occluded within the crystal lattice. This promises an elegant means of creating nanocomposites and tuning physical properties. Here we use the incorporation of sulfonated fluorescent dyes to gain new understanding of additive occlusion in calcite (CaCO3), and to link morphological changes to occlusion mechanisms. We demonstrate that these additives are incorporated within specific zones, as defined by the growth conditions, and show how occlusion can govern changes in crystal shape. Fluorescence spectroscopy and lifetime imaging microscopy also show that the dyes experience unique local environments within different zones. Our strategy is then extended to simultaneously incorporate mixtures of dyes, whose fluorescence cascade creates calcite nanoparticles that fluoresce white. This offers a simple strategy for generating biocompatible and stable fluorescent nanoparticles whose output can be tuned as required.

No MeSH data available.


Related in: MedlinePlus

Direct comparison of local GREEN environment by FLIM.(a) Optical micrograph of ACC after extended exposure to reaction solution. (b) CFM reveals calcite embedded amongst bulk ACC, with greater fluorescence intensity associated with the crystalline phase compared with the amorphous. (c) FLIM micrograph revealing differences in fluorescent lifetime between crystalline (i and ii) compared with amorphous (iii). (d) Global fluorescence decays obtained for regions of interest i (black), ii (red) and iii (blue) in c yielding fluorescence lifetime τ=3.9, 3.9 and 5.2 ns, respectively. Scale bars, 20 μm (a–c).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC5120221&req=5

f6: Direct comparison of local GREEN environment by FLIM.(a) Optical micrograph of ACC after extended exposure to reaction solution. (b) CFM reveals calcite embedded amongst bulk ACC, with greater fluorescence intensity associated with the crystalline phase compared with the amorphous. (c) FLIM micrograph revealing differences in fluorescent lifetime between crystalline (i and ii) compared with amorphous (iii). (d) Global fluorescence decays obtained for regions of interest i (black), ii (red) and iii (blue) in c yielding fluorescence lifetime τ=3.9, 3.9 and 5.2 ns, respectively. Scale bars, 20 μm (a–c).

Mentions: The difference in fluorescence of GREEN occluded in ACC and calcite was also demonstrated by allowing a small amount of crystallization of ACC to calcite. While calcite crystals were not distinguishable in the mineral powder by optical microscopy (Fig. 6a), they were readily distinguished using CFM thanks to their higher brightness as compared with the ACC background (Fig. 6b). This difference was also observed on comparing the average grey values from areas attributed to amorphous and crystalline phases, where FLIM demonstrated lifetimes for dyes associated with amorphous and crystalline hosts of τ=5.2 and 3.9 ns, respectively (Fig. 6c,d).


3D visualization of additive occlusion and tunable full-spectrum fluorescence in calcite
Direct comparison of local GREEN environment by FLIM.(a) Optical micrograph of ACC after extended exposure to reaction solution. (b) CFM reveals calcite embedded amongst bulk ACC, with greater fluorescence intensity associated with the crystalline phase compared with the amorphous. (c) FLIM micrograph revealing differences in fluorescent lifetime between crystalline (i and ii) compared with amorphous (iii). (d) Global fluorescence decays obtained for regions of interest i (black), ii (red) and iii (blue) in c yielding fluorescence lifetime τ=3.9, 3.9 and 5.2 ns, respectively. Scale bars, 20 μm (a–c).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5120221&req=5

f6: Direct comparison of local GREEN environment by FLIM.(a) Optical micrograph of ACC after extended exposure to reaction solution. (b) CFM reveals calcite embedded amongst bulk ACC, with greater fluorescence intensity associated with the crystalline phase compared with the amorphous. (c) FLIM micrograph revealing differences in fluorescent lifetime between crystalline (i and ii) compared with amorphous (iii). (d) Global fluorescence decays obtained for regions of interest i (black), ii (red) and iii (blue) in c yielding fluorescence lifetime τ=3.9, 3.9 and 5.2 ns, respectively. Scale bars, 20 μm (a–c).
Mentions: The difference in fluorescence of GREEN occluded in ACC and calcite was also demonstrated by allowing a small amount of crystallization of ACC to calcite. While calcite crystals were not distinguishable in the mineral powder by optical microscopy (Fig. 6a), they were readily distinguished using CFM thanks to their higher brightness as compared with the ACC background (Fig. 6b). This difference was also observed on comparing the average grey values from areas attributed to amorphous and crystalline phases, where FLIM demonstrated lifetimes for dyes associated with amorphous and crystalline hosts of τ=5.2 and 3.9 ns, respectively (Fig. 6c,d).

View Article: PubMed Central - PubMed

ABSTRACT

From biomineralization to synthesis, organic additives provide an effective means of controlling crystallization processes. There is growing evidence that these additives are often occluded within the crystal lattice. This promises an elegant means of creating nanocomposites and tuning physical properties. Here we use the incorporation of sulfonated fluorescent dyes to gain new understanding of additive occlusion in calcite (CaCO3), and to link morphological changes to occlusion mechanisms. We demonstrate that these additives are incorporated within specific zones, as defined by the growth conditions, and show how occlusion can govern changes in crystal shape. Fluorescence spectroscopy and lifetime imaging microscopy also show that the dyes experience unique local environments within different zones. Our strategy is then extended to simultaneously incorporate mixtures of dyes, whose fluorescence cascade creates calcite nanoparticles that fluoresce white. This offers a simple strategy for generating biocompatible and stable fluorescent nanoparticles whose output can be tuned as required.

No MeSH data available.


Related in: MedlinePlus