A reduced graphene oxide-based fluorescence resonance energy transfer sensor for highly sensitive detection of matrix metalloproteinase 2

Abstract

A novel fluorescence nanoprobe (reduced nano-graphene oxide [nrGO]/fluorescein isothiocyanate-labeled peptide [Pep-FITC]) for ultrasensitive detection of matrix metalloproteinase 2 (MMP2) has been developed by engineering the Pep-FITC comprising the specific MMP2 substrate domain (PLGVR) onto the surface of nrGO particles through non-covalent linkage. The nrGO was obtained by water bathing nano-graphene oxide under 90°C for 4 hours. After mixing the nrGO and Pep-FITC for 30 seconds, the fluorescence from Pep-FITC was almost completely quenched due to the fluorescence resonance energy transfer between fluorescein isothiocyanate (FITC) and nrGO. Upon cleavage of the amide bond between Leu and Gly in the Pep-FITC by protease-MMP2, the FITC bound to nrGO was separated from nrGO surface, disrupting the fluorescence resonance energy transfer process and resulting in fluorescence recovery of FITC. Under optimal conditions, the fluorescence recovery of nrGO/Pep-FITC was found to be directly proportional to the concentration of MMP2 within 0.02–0.1 nM. The detection limit of the nrGO/Pep-FITC was determined to be 3 pM, which is approximately tenfold lower than that of the unreduced carboxylated nano-graphene oxide/Pep-FITC probe.

Keywords:

• graphene oxide
• reduction
• high sensitive detection
• fluorescence

Acknowledgments

This work was supported by the National Natural Science Foundation of China (Nos 61527825, 81471699, and 61178078) and the Guangdong Province Science and Technology Plan Project (2014B090901060) as well as the Guangzhou Science and Technology Plan Project (No 2014J4100055).

Author contributions

Tongsheng Chen and Xiaoping Wang contributed to conception and study design. Gaina Xi was involved in data acquisition. Gaina Xi and Tongsheng Chen were involved in data analysis and interpretation. Gaina Xi performed the statistical analyses. Gaina Xi and Tongsheng Chen drafted the article. All of the authors contributed to writing and revising the manuscript for scientific content, approved the final version before submission and agree to be accountable for all aspects of the work.

Disclosure

The authors report no conflicts of interest in this work.