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Polyamine Colloids Cross‐Linked with Phosphate Ions: Towards Understanding the Solution Phase Behavior
Author(s) -
Herrera Santiago E.,
Agazzi Maximiliano L.,
Cortez M. Lorena,
Marmisollé Waldemar A.,
Tagliazucchi Mario,
Azzaroni Omar
Publication year - 2019
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201900046
Subject(s) - ionic strength , allylamine , colloid , chemistry , aqueous solution , ionic bonding , phosphate , nanocarriers , chemical engineering , polyelectrolyte , supramolecular chemistry , ion , inorganic chemistry , drug delivery , organic chemistry , molecule , polymer , engineering
Ionically crosslinked poly(allylamine)/phosphate (PAH/Pi) colloids consist of self‐assembled nanostructures stabilized by supramolecular interactions. Under physiological conditions, these interactions should be present at high ionic strength and only in a narrow pH window to be effective as drug delivery agents. In this work we study the effect of the pH and ionic strength in the chemical behaviour of inorganic phosphate (Pi), poly(allylamine hydrochloride) (PAH) and their mixture in aqueous solution (PAH−Pi). By combination of experimental measurements and a theoretical model, we demonstrate that the driving force that leads to the formation of colloids is the electrostatic pairing between the positively charged amino groups in PAH and negatively charged HPO 4 2− ions. Increasing the ionic strength of the system by addition of KCl weakens the PAH−Pi interactions and narrows the pH stability window from 4 to 1.8 pH units. In addition, a fully reversible system was obtained in which the colloids assemble and disassemble by changing the pH between 6.8 and 7.1 at high ionic strength, making them suitable for use as pH‐responsive nanocarriers.