Chemical specificity in REDOX-responsive materials: the diverse effects of different Reactive Oxygen Species (ROS) on polysulfide nanoparticles

Damien Jeanmaire, Jureerat Laliturai, Abdulaziz Almalik, Paolo Carampin, Richard D'Arcy, Enrique Lallana, Robert Evans, Richard E P Winpenny, Nicola Tirelli*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


REDOX responsive (nano)materials typically exhibit chemical changes in response to the presence and concentration of oxidants/reductants. Due to the complexity of biological environments, it is critical to ascertain whether the chemical response may depend on the chemical details of the stimulus, in addition to its REDOX potential, and whether chemically different responses can determine a different overall performance of the material. Here, we have used oxidation-sensitive materials, although these considerations can be extended also to reducible ones. In particular, we have used poly(propylene sulfide) (PPS) nanoparticles coated with a PEGylated emulsifier (Pluronic F127); inter alia, we here present also an improved preparative method. The nanoparticles were exposed to two Reactive Oxygen Species (ROS) typically encountered in inflammatory reactions, hydrogen peroxide (H2O2) and hypochlorite (ClO); their response was evaluated with a variety of techniques, including diffusion NMR spectroscopy that allowed to separately characterize the chemically different colloidal species produced. The two oxidants triggered a different chemical response: H2O2 converted sulfides to sulfoxides, while ClO partially oxidized them further to sulfones. The different chemistry correlated to a different material response: H2O2 increased the polarity of the nanoparticles, causing them to swell in water and to release the surface PEGylated emulsifier; the uncoated oxidized particles still exhibited very low toxicity. On the contrary, ClO rapidly converted the nanoparticles into water-soluble, depolymerized fragments with a significantly higher toxicity. The take-home message is that it is more correct to discuss ‘smart’ materials in terms of an environmentally specific response to (REDOX) stimuli. Far from being a problem, this could open the way to more sophisticated and precisely targeted applications.

Original languageEnglish
Pages (from-to)1393-1404
Number of pages12
JournalPolymer Chemistry
Issue number4
Early online date19 Nov 2013
Publication statusPublished - 21 Feb 2014

Bibliographical note

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.

Funding: Financial support from EPSRC (grant no. EP/C543564/1)


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