Thermo-responsive adsorption and separation of amino acid enantiomers using smart polymer-brush-modified magnetic nanoparticles

Abstract

A novel type of multifunctional magnetic nanoparticle with highly chiral recognition capability, excellent thermo-sensitive adsorption and decomplexation properties toward amino acid enantiomers, and recyclability was developed in this study.

Novel Smart Polymer-Brush-Modified Magnetic Graphene Oxide for Highly Efficient Chiral Recognition and Enantioseparation of Tryptophan Enantiomers

“…Plentiful of β-CD units in PNG-CD contain abundant −OH groups, which can interact with numerous water molecules via hydrogen bond interaction, thus causing a noticeable weight loss at temperatures below 150 °C. The immobilizing amount of β-CD onto the MGO@PNG-CD is calculated to be 0.27 mmol/g from the TGA data, 9 times as much as that of Fe 3 O 4 NPs (0.03 mmol/g) . This would be beneficial to boost the enantioselectivity of the synthesized smart graphene nanoselector.…”

“…More importantly, the thermoresponsive volume phase transition of PNIPAM chains in response to a temperature variation can significantly affect the inclusion constants of β-CD and the recognized guests in the PNIPAM-β-CD. , Inspired by which, we developed one novel magnetic nanoselector (Fe 3 O 4 @PNG-CD) through grafting PNG-CD smart polymer brushes onto Fe 3 O 4 NPs. The PNG-CD is made up of poly­( N -isopropylacrylamide- co -glycidyl methacrylate) (PNG) chains with abundant appended β-CD units . And the resulted Fe 3 O 4 @PNG-CD was successfully utilized in the chiral discrimination and enantioseparation of AAs enantiomers, and through simply varying the operating temperature the desorption of the loaded enantiomers and the regeneration of the smart nanoselector could be easily fulfilled.…”

“…Consequently, the binding amount of β-CD onto the Fe 3 O 4 @PNG-CD is very limited (only 0.03 mmol/g). Therefore, the enantioselectivity of the Fe 3 O 4 @PNG-CD toward AAs enantiomers is not high …”

“…The PNG-CD is made up of poly(N-isopropylacrylamide-co-glycidyl methacrylate) (PNG) chains with abundant appended β-CD units. 33 And the resulted Fe 3 O 4 @PNG-CD was successfully utilized in the chiral discrimination and enantioseparation of AAs enantiomers, and through simply varying the operating temperature the desorption of the loaded enantiomers and the regeneration of the smart nanoselector could be easily fulfilled. However, due to a relatively small specific surface area of Fe 3 O 4 NPs (47.15 m 2 /g), 34 the grafting amount of PNG chains onto the Fe 3 O 4 NPs is not high (32.2 mg/g).…”

“…Therefore, the enantioselectivity of the Fe 3 O 4 @PNG-CD toward AAs enantiomers is not high. 33 Graphene oxide (GO) is a two-dimensional monolayer carbon material characteristic of ultrahigh specific surface area (theoretically calculated value 2630 m 2 /g) and abundant oxygen-containing groups on its honeycomb lattice. 35 The unique properties of GO make it or its derivatives have wide application potentials in environment-related fields.…”