A supramolecular microgel glutathione peroxidase mimic with temperature responsive activity

Abstract

Glutathione peroxidase (GPx) protects cells from oxidative damage by scavenging surplus reactive oxygen species (ROS). Commonly, an appropriate amount of ROS acts as a signal molecule in the metabolism. A smart artificial GPx exhibits adjustable catalytic activity, which can potentially reduce the amount of ROS to an appropriate degree and maintain its important physiological functions in metabolism. To construct an optimum and excellent smart artificial GPx, a novel supramolecular microgel artificial GPx (SM-Te) was prepared based on the supramolecular host-guest interaction employing the tellurium-containing guest molecule (ADA-Te-ADA) and the cyclodextrin-containing host block copolymer (poly(N-isopropylacrylamide)-b-[polyacrylamides-co-poly(6-o-(triethylene glycol monoacrylate ether)-β-cyclodextrin)], PPAM-CD) as building blocks. Subsequently, based on these building blocks, SM-Te was constructed and the formation of its self-assembled structure was confirmed by dynamic light scattering, NMR, SEM, TEM, etc. Typically, benefitting from the temperature responsive properties of the PNIPAM scaffold, SM-Te also exhibited similar temperature responsive behaviour. Importantly, the GPx catalytic rates of SM-Te displayed a noticeable temperature responsive characteristic. Moreover, SM-Te exhibited the typical saturation kinetics behaviour of a real enzyme catalyst. It was proved that the changes of the hydrophobic microenvironment and the pore size in the supramolecular microgel network of SM-Te played significant roles in altering the temperature responsive catalytic behaviour. The successful construction of SM-Te not only overcomes the insurmountable disadvantages existing in previous covalent bond crosslinked microgel artificial GPx but also bodes well for the development of novel intelligent antioxidant drugs.

Construction of a smart microgel glutathione peroxidase mimic based on supramolecular self-assembly

“…The similar structure has been reported in our previous report. 17 Such unique structural characteristics of PPAM-ADA-Te provide further evidence for the formation of a supramolecular microgel based on the host-guest self-assembly of PPAM-ADA with CD-Te-CD.…”

“…The synthesis of PPAM-ADA was similar to the synthesis of PPAM-CD mentioned in our previous report, 17 except the CD-monomer was replaced by ADA-monomer. GPC analysis of PPAM-ADA revealed a M n of 13 070, M w of 16 290 and a polydispersity, M w /M n , of 1.25.…”

Facile Construction of Microgel based Biomimetic Glutathione Peroxidase with Temperature Responsive Catalytic Activity

“…However, they presented a limitation in elucidating the catalytic mechanism of natural GPx due to the difficulty in simulating the synergistic catalysis process. In order to address this issue, hyperbranched polymers, block polymers, microgels and other macromolecules were used to construct biomimetic GPxs due to the facile tailor of the scaffold structure and the easy modification with various catalytic elements. The diverse structures and catalytic elements provided conveniences for the synergistic catalysis of biomimetic GPx.…”

“…Besides, the biomimetic GPx based on macromolecular polymers could be industrialized easily . Therefore, considerable efforts have been devoted to construct biomimetic GPxs based on macromolecular polymers . Additionally, supramolecular could be also modified with various catalytic elements for simulating GPx .…”

“…Therefore, considerable efforts have been devoted to construct biomimetic GPxs based on macromolecular polymers . Additionally, supramolecular could be also modified with various catalytic elements for simulating GPx . To some extent, however, the strict preparation conditions of supramolecular assemblies and the complicated synthesis process of supramolecular assembling units limited the efficient construction of these biomimetic GPxs and their further industrial application.…”