Effects of alginate on cellular iron transport.

<p>(A) Intracellular iron concentration decreases when RKO cells were incubated with iron-59 and alginate (0.3% w/v) compared to iron only control (B) Treatment of RKO cells with iron increases ferritin expression whilst co-incubation with alginate (0.3% w/v) significantly suppressed the iron mediated ferritin induction. All experiments were performed in triplicate with error bars representing +/- SEM and * denotes statistical significance at p < 0.05.</p

Synthesis of FITC alginate.

<p>(Ai) Reaction coupling scheme of FITC onto alginate under peptide coupling conditions. (Aii) Image of fluorescent alginate in normal light (left) and exposed to λ = 365 nm UV light (right). (B) Absorption and emission (red and blue lines respectively) spectra of the fluorescent alginate (FlAlg) product. The native alginate reactant has no absorption or emission profile, however, upon conjugation with FITC a highly absorption and emission peaks are observed.</p

Cellular localisation of alginate with confocal microscopy.

<p>Cells were treated with iron alone (control) or iron and FITC alginate with or without cell-membrane permeabilisation. (A) Cells treated with iron alone as expected showed no FITC signal. (B) Cells treated with iron and FITC alginate showed negligible punctate FITC staining on the cell periphery (C) Cells permeabilised with Saponin and then cultured with iron and FITC alginate showed an abundance of intracellular FITC signal which was mostly cytoplasmic in localisation.</p

Physical characterisation of alginate iron composites.

<p>(Ai) Low magnification STEM images of alginate-iron composites revealed the alginate network ‘decorated’ in iron (denoted by arrows) with a single highly dense iron nucleation site (denoted with an asterisk). (Aii) A higher magnification image of the nucleation centre revealed nanoparticles of approximately 2–5 nm in diameter. (B) Fast Fourier transform analysis of HAADF-STEM images of two individual nanoparticles. (C) EDX mapping of iron-alginate composites with oxygen, iron and sodium localisation shown in the sample area. The copper from the copper TEM grid functions as a control.</p

Chemical analysis of iron alginate binding.

<p>(Ai) Isothermal titration microcalorimetry thermogram of 8 μl injectants of 5 mM Fe(III) into 0.04 mM alginate at 37°C. (Aii) Corresponding isotherm. (Bi) UV-Visible difference spectra of iron (III) titrated into alginate with a clear absorbance change at ca. 280 nm (Bii) absorbance change at 274nm vs final Fe concentration (M) with binding curve) (C) CD spectra of alginate-iron composites isolated via equilibrium dialysis. An induced CD signal is evident at ca. 280 nm. This correlates to the iron-hydroxide species bonded to the alginate as indicated from the UV-Visible spectra.</p