We describe the preparation and properties of the first example of a synergic nanoantioxidant, obtained by different functionalizations of the external surface and the inner lumen of halloysite nanotubes (HNTs). Trolox, a mimic of natural α-tocopherol, was selectively grafted on the HNT external surface; while quercetin, a natural polyphenolic antioxidant, was loaded into the inner lumen to afford a bi-functional nanoantioxidant, HNT–Trolox/Que, which was investigated for its reactivity with transient peroxyl radicals and a persistent 1,1-diphenyl-2-picrylhydrazyl (DPPH˙) radical in comparison with the corresponding mono-functional analogues HNT–Trolox and HNT/Que. Both HNT–Trolox and HNT/Que showed good antioxidant performance in the inhibited autoxidation of organic substrates; however HNT–Trolox/Que protection by reaction with peroxyl radicals was 35% higher in acetonitrile and 65% in chlorobenzene, as compared to the expected performance based on the sum of contributions of NHT-Trolox and NHT/Que. Similar enhancement was observed also in the trapping of DPPH˙ radicals. Synergism between the distinct antioxidant functions was based on the rapid reaction of externally exposed Trolox (rate constant with peroxyl radicals was 1.1 × 106 M−1 s−1 and 9 × 104 M−1 s−1 respectively in chlorobenzene and acetonitrile, at 30 °C), followed by its regeneration by quercetin released from the HNT lumen. The advantages of this novel nanoantioxidant are discussed.

A synergic nanoantioxidant based on covalently modified halloysite–trolox nanotubes with intra-lumen loaded quercetin / Massaro, Marina; Riela, Serena; Guernelli, Susanna; Parisi, Filippo; Lazzara, Giuseppe; Baschieri, Andrea; Valgimigli, Luca; Amorati, Riccardo. - In: JOURNAL OF MATERIALS CHEMISTRY. B. - ISSN 2050-750X. - STAMPA. - 4:(2016), pp. 2229-2241. [10.1039/c6tb00126b]

A synergic nanoantioxidant based on covalently modified halloysite–trolox nanotubes with intra-lumen loaded quercetin

GUERNELLI, SUSANNA;BASCHIERI, ANDREA;VALGIMIGLI, LUCA;AMORATI, RICCARDO
2016

Abstract

We describe the preparation and properties of the first example of a synergic nanoantioxidant, obtained by different functionalizations of the external surface and the inner lumen of halloysite nanotubes (HNTs). Trolox, a mimic of natural α-tocopherol, was selectively grafted on the HNT external surface; while quercetin, a natural polyphenolic antioxidant, was loaded into the inner lumen to afford a bi-functional nanoantioxidant, HNT–Trolox/Que, which was investigated for its reactivity with transient peroxyl radicals and a persistent 1,1-diphenyl-2-picrylhydrazyl (DPPH˙) radical in comparison with the corresponding mono-functional analogues HNT–Trolox and HNT/Que. Both HNT–Trolox and HNT/Que showed good antioxidant performance in the inhibited autoxidation of organic substrates; however HNT–Trolox/Que protection by reaction with peroxyl radicals was 35% higher in acetonitrile and 65% in chlorobenzene, as compared to the expected performance based on the sum of contributions of NHT-Trolox and NHT/Que. Similar enhancement was observed also in the trapping of DPPH˙ radicals. Synergism between the distinct antioxidant functions was based on the rapid reaction of externally exposed Trolox (rate constant with peroxyl radicals was 1.1 × 106 M−1 s−1 and 9 × 104 M−1 s−1 respectively in chlorobenzene and acetonitrile, at 30 °C), followed by its regeneration by quercetin released from the HNT lumen. The advantages of this novel nanoantioxidant are discussed.
2016
A synergic nanoantioxidant based on covalently modified halloysite–trolox nanotubes with intra-lumen loaded quercetin / Massaro, Marina; Riela, Serena; Guernelli, Susanna; Parisi, Filippo; Lazzara, Giuseppe; Baschieri, Andrea; Valgimigli, Luca; Amorati, Riccardo. - In: JOURNAL OF MATERIALS CHEMISTRY. B. - ISSN 2050-750X. - STAMPA. - 4:(2016), pp. 2229-2241. [10.1039/c6tb00126b]
Massaro, Marina; Riela, Serena; Guernelli, Susanna; Parisi, Filippo; Lazzara, Giuseppe; Baschieri, Andrea; Valgimigli, Luca; Amorati, Riccardo
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/541506
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