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Tuning Pluronic F127 phase transitions by adding physiological amounts of salts : A rheology, SAXS, and NMR investigation

Russo, Giovanni ; Rossella Delpiano, G. ; Carucci, Cristina LU orcid ; Grosso, Massimiliano ; Dessì, Claudia ; Söderman, Olle LU ; Lindman, Björn LU ; Monduzzi, Maura and Salis, Andrea LU (2024) In European Polymer Journal 204.
Abstract

Specific ion (Hofmeister) effects in colloid and biological systems represented a scientific challenge for more than 100 years. Recently, possible applications, based on their rationalization, are emerging. Here, Cl-, SO42-, SCN- anions and Na+, K+, Mg2+ cations are added at physiological concentration (∼0.15 mol/kg) to Pluronic F127 20 wt% aqueous solutions to suitably tune phase transitions for a smart drug delivery platform. Rheological measurements, along with SAXS and NMR self-diffusion experiments, are used to carefully characterize the prepared F127/salt-based formulations. The critical micellar temperature (cmt), the hard-gel formation temperature... (More)

Specific ion (Hofmeister) effects in colloid and biological systems represented a scientific challenge for more than 100 years. Recently, possible applications, based on their rationalization, are emerging. Here, Cl-, SO42-, SCN- anions and Na+, K+, Mg2+ cations are added at physiological concentration (∼0.15 mol/kg) to Pluronic F127 20 wt% aqueous solutions to suitably tune phase transitions for a smart drug delivery platform. Rheological measurements, along with SAXS and NMR self-diffusion experiments, are used to carefully characterize the prepared F127/salt-based formulations. The critical micellar temperature (cmt), the hard-gel formation temperature (Thg), liquid crystal structures, and self-diffusion coefficients are determined. The cmt and Thg values of F127/salt formulations are lower than that of F127 20 wt% sample, following an anionic Hofmeister series: SO42- < Cl- < SCN-. All added salts significantly increase storage modulus and complex viscosity with maximum values occurring at T around 40 °C. SAXS data confirm that added salts preserve cubic liquid crystal phases. NMR self-diffusion analysis highlights that the intermolecular interactions and mobility of F127 unimers/aggregates are ion specific at 16 °C but not at 40 °C. These findings suggest that F127/salt-based formulations may constitute a versatile thermosensitive platform for drug delivery able to assure sustained release in topical or surgery administrations, in the range of temperatures 30–45 °C.

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; ; ; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Hofmeister series, Pluronic F127, Thermoresponsive hydrogels, Tunable phase transitions
in
European Polymer Journal
volume
204
article number
112714
publisher
Elsevier
external identifiers
  • scopus:85181115966
ISSN
0014-3057
DOI
10.1016/j.eurpolymj.2023.112714
language
English
LU publication?
yes
id
ea9d0962-5d99-4d81-8a3a-ab5cd68309c2
date added to LUP
2024-02-09 14:56:34
date last changed
2024-02-09 14:58:35
@article{ea9d0962-5d99-4d81-8a3a-ab5cd68309c2,
  abstract     = {{<p>Specific ion (Hofmeister) effects in colloid and biological systems represented a scientific challenge for more than 100 years. Recently, possible applications, based on their rationalization, are emerging. Here, Cl<sup>-</sup>, SO<sub>4</sub><sup>2-</sup>, SCN<sup>-</sup> anions and Na<sup>+</sup>, K<sup>+</sup>, Mg<sup>2+</sup> cations are added at physiological concentration (∼0.15 mol/kg) to Pluronic F127 20 wt% aqueous solutions to suitably tune phase transitions for a smart drug delivery platform. Rheological measurements, along with SAXS and NMR self-diffusion experiments, are used to carefully characterize the prepared F127/salt-based formulations. The critical micellar temperature (cmt), the hard-gel formation temperature (T<sub>hg</sub>), liquid crystal structures, and self-diffusion coefficients are determined. The cmt and T<sub>hg</sub> values of F127/salt formulations are lower than that of F127 20 wt% sample, following an anionic Hofmeister series: SO<sub>4</sub><sup>2-</sup> &lt; Cl<sup>-</sup> &lt; SCN<sup>-</sup>. All added salts significantly increase storage modulus and complex viscosity with maximum values occurring at T around 40 °C. SAXS data confirm that added salts preserve cubic liquid crystal phases. NMR self-diffusion analysis highlights that the intermolecular interactions and mobility of F127 unimers/aggregates are ion specific at 16 °C but not at 40 °C. These findings suggest that F127/salt-based formulations may constitute a versatile thermosensitive platform for drug delivery able to assure sustained release in topical or surgery administrations, in the range of temperatures 30–45 °C.</p>}},
  author       = {{Russo, Giovanni and Rossella Delpiano, G. and Carucci, Cristina and Grosso, Massimiliano and Dessì, Claudia and Söderman, Olle and Lindman, Björn and Monduzzi, Maura and Salis, Andrea}},
  issn         = {{0014-3057}},
  keywords     = {{Hofmeister series; Pluronic F127; Thermoresponsive hydrogels; Tunable phase transitions}},
  language     = {{eng}},
  publisher    = {{Elsevier}},
  series       = {{European Polymer Journal}},
  title        = {{Tuning Pluronic F127 phase transitions by adding physiological amounts of salts : A rheology, SAXS, and NMR investigation}},
  url          = {{http://dx.doi.org/10.1016/j.eurpolymj.2023.112714}},
  doi          = {{10.1016/j.eurpolymj.2023.112714}},
  volume       = {{204}},
  year         = {{2024}},
}