Synthesis of double-clickable functionalised graphene oxide for biological applications.

Kuo-Ching Mei,Vincenzo Abbate,Khuloud T Al-Jamal,Pedro M Costa,Noelia Rubio,Sukhvinder S Bansal,Frederic Festy,Houmam Kafa,Robert C Hider

doi:10.1039/c5cc05412e

Abstract

Azide- and alkyne-double functionalised graphene oxide (Click(2) GO) was synthesised and characterised with attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), thermogravimetric analysis (TGA) and Raman spectroscopy. Fourteen-percentage increase in azide content was found, after pre-treatment of GO with meta-chloroperoxybenzoic acid (mCPBA), determined with elemental analysis. No effect on A549 cell viability was found, up to 100 μg mL(-1) and 72 h of incubation, determined with the modified lactate dehydrogenase (mLDH) assay. Two sequential copper(i) catalysed azide-alkyne cycloaddition (CuAAC) reactions were performed to conjugate the propargyl-modified blood-brain barrier targeting peptide Angiopep-2, and a bis-azide polyethylene glycol (MW = 3500), to the Click(2) GO. The final conjugate was characterised with ATR-FTIR and TGA.

Highlights

Azide- and alkyne-double functionalised graphene oxide was synthesised and characterised
The final conjugate was characterised with ATR-FTIR and thermogravimetric analysis (TGA)
Graphene and graphene oxide (GO) are single atom thick, 2-D carbon structures that have recently been widely used in many fields including drug delivery,[1,2] gas separation,[3] electrochemical sensing, biosensing,[4,5] bio-imaging and photothermal therapy.[6]

Summary

Introduction

Azide- and alkyne-double functionalised graphene oxide was synthesised and characterised. Two sequential copper(I) catalysed azide–alkyne cycloadditions (CuAACs), i.e. click reactions, were performed to conjugate the propargyl-modified blood–brain barrier targeting peptide Angiopep-2, and a bis-azide polyethylene glycol, to the Click[2] GO. Azide- and alkyne-double functionalised graphene oxide (Click[2] GO) was synthesised and characterised with attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), thermogravimetric analysis (TGA) and Raman spectroscopy.

Results

Conclusion