TY - JOUR
T1 - Chemical specificity in REDOX-responsive materials
T2 - the diverse effects of different Reactive Oxygen Species (ROS) on polysulfide nanoparticles
AU - Jeanmaire, Damien
AU - Laliturai, Jureerat
AU - Almalik, Abdulaziz
AU - Carampin, Paolo
AU - D'Arcy, Richard
AU - Lallana, Enrique
AU - Evans, Robert
AU - Winpenny, Richard E P
AU - Tirelli, Nicola
N1 - This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.
Funding: Financial support from EPSRC (grant no. EP/C543564/1)
PY - 2014/2/21
Y1 - 2014/2/21
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=84892911215&partnerID=8YFLogxK
UR - http://pubs.rsc.org/en/Content/ArticleLanding/2014/PY/c3py01475d#!divAbstract
U2 - 10.1039/c3py01475d
DO - 10.1039/c3py01475d
M3 - Article
AN - SCOPUS:84892911215
SN - 1759-9954
VL - 5
SP - 1393
EP - 1404
JO - Polymer Chemistry
JF - Polymer Chemistry
IS - 4
ER -