Limits...
Alginate-Iron Speciation and Its Effect on In Vitro Cellular Iron Metabolism.

Horniblow RD, Dowle M, Iqbal TH, Latunde-Dada GO, Palmer RE, Pikramenou Z, Tselepis C - PLoS ONE (2015)

Bottom Line: However, the synthesis of iron oxide nanoparticles employs non-physiological pH conditions and whether nanoparticle formation in vivo is responsible for influencing cellular iron metabolism is unclear.The interaction of alginate and iron at a cellular level was found to decrease cellular iron acquisition by 37% (p < 0.05) and in combination with confocal microscopy the alginate inhibits cellular iron transport through extracellular iron chelation with the resulting complexes not internalised.These results infer alginate as being useful in the chelation of excess iron, especially in the context of inflammatory bowel disease and colorectal cancer where excess unabsorbed luminal iron is thought to be a driver of disease.

View Article: PubMed Central - PubMed

Affiliation: University of Birmingham, School of Cancer Sciences, College of Medical and Dental Sciences, Vincent Drive, Edgbaston, Birmingham, B15 2TT, United Kingdom.

ABSTRACT
Alginates are a class of biopolymers with known iron binding properties which are routinely used in the fabrication of iron-oxide nanoparticles. In addition, alginates have been implicated in influencing human iron absorption. However, the synthesis of iron oxide nanoparticles employs non-physiological pH conditions and whether nanoparticle formation in vivo is responsible for influencing cellular iron metabolism is unclear. Thus the aims of this study were to determine how alginate and iron interact at gastric-comparable pH conditions and how this influences iron metabolism. Employing a range of spectroscopic techniques under physiological conditions alginate-iron complexation was confirmed and, in conjunction with aberration corrected scanning transmission electron microscopy, nanoparticles were observed. The results infer a nucleation-type model of iron binding whereby alginate is templating the condensation of iron-hydroxide complexes to form iron oxide centred nanoparticles. The interaction of alginate and iron at a cellular level was found to decrease cellular iron acquisition by 37% (p < 0.05) and in combination with confocal microscopy the alginate inhibits cellular iron transport through extracellular iron chelation with the resulting complexes not internalised. These results infer alginate as being useful in the chelation of excess iron, especially in the context of inflammatory bowel disease and colorectal cancer where excess unabsorbed luminal iron is thought to be a driver of disease.

No MeSH data available.


Related in: MedlinePlus

Synthesis of FITC alginate.(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.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4574481&req=5

pone.0138240.g004: Synthesis of FITC alginate.(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.

Mentions: Since alginate depleted intracellular iron, confocal microscopy was performed to assess the localisation of the alginate in these cell culture experiments and specifically to deduce if the alginate is internalised. To assess the bioavailability of alginate LFR5/60 and the composites formed upon interaction with iron a fluorescent analogue was prepared by conjugation with fluoresceinamine (FITC) as schematically illustrated in Fig 4Ai. Absorption and emission spectra were recorded for the fluorescent alginate with absorption and emission maxima (λmax) at ca. 490 and 550 nm respectively (Fig 4B).


Alginate-Iron Speciation and Its Effect on In Vitro Cellular Iron Metabolism.

Horniblow RD, Dowle M, Iqbal TH, Latunde-Dada GO, Palmer RE, Pikramenou Z, Tselepis C - PLoS ONE (2015)

Synthesis of FITC alginate.(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.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4574481&req=5

pone.0138240.g004: Synthesis of FITC alginate.(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.
Mentions: Since alginate depleted intracellular iron, confocal microscopy was performed to assess the localisation of the alginate in these cell culture experiments and specifically to deduce if the alginate is internalised. To assess the bioavailability of alginate LFR5/60 and the composites formed upon interaction with iron a fluorescent analogue was prepared by conjugation with fluoresceinamine (FITC) as schematically illustrated in Fig 4Ai. Absorption and emission spectra were recorded for the fluorescent alginate with absorption and emission maxima (λmax) at ca. 490 and 550 nm respectively (Fig 4B).

Bottom Line: However, the synthesis of iron oxide nanoparticles employs non-physiological pH conditions and whether nanoparticle formation in vivo is responsible for influencing cellular iron metabolism is unclear.The interaction of alginate and iron at a cellular level was found to decrease cellular iron acquisition by 37% (p < 0.05) and in combination with confocal microscopy the alginate inhibits cellular iron transport through extracellular iron chelation with the resulting complexes not internalised.These results infer alginate as being useful in the chelation of excess iron, especially in the context of inflammatory bowel disease and colorectal cancer where excess unabsorbed luminal iron is thought to be a driver of disease.

View Article: PubMed Central - PubMed

Affiliation: University of Birmingham, School of Cancer Sciences, College of Medical and Dental Sciences, Vincent Drive, Edgbaston, Birmingham, B15 2TT, United Kingdom.

ABSTRACT
Alginates are a class of biopolymers with known iron binding properties which are routinely used in the fabrication of iron-oxide nanoparticles. In addition, alginates have been implicated in influencing human iron absorption. However, the synthesis of iron oxide nanoparticles employs non-physiological pH conditions and whether nanoparticle formation in vivo is responsible for influencing cellular iron metabolism is unclear. Thus the aims of this study were to determine how alginate and iron interact at gastric-comparable pH conditions and how this influences iron metabolism. Employing a range of spectroscopic techniques under physiological conditions alginate-iron complexation was confirmed and, in conjunction with aberration corrected scanning transmission electron microscopy, nanoparticles were observed. The results infer a nucleation-type model of iron binding whereby alginate is templating the condensation of iron-hydroxide complexes to form iron oxide centred nanoparticles. The interaction of alginate and iron at a cellular level was found to decrease cellular iron acquisition by 37% (p < 0.05) and in combination with confocal microscopy the alginate inhibits cellular iron transport through extracellular iron chelation with the resulting complexes not internalised. These results infer alginate as being useful in the chelation of excess iron, especially in the context of inflammatory bowel disease and colorectal cancer where excess unabsorbed luminal iron is thought to be a driver of disease.

No MeSH data available.


Related in: MedlinePlus