Matrix Metalloproteinase Sensing in Wound Fluids: Are Graphene-Based Field Effect Transistors a Viable Alternative?

Wound dressings based on graphene sheets are expected to play a crucial role in wound treatment. The good conductivity and charge mobility of graphene as an electronic material makes graphene-based field effect transistors well-adapted for sensing of wound biomarkers. In this work, an aptamer-based field effect transistor using graphene as sensing channel material was developed and evaluated for the selective and sensitive monitoring of matrix metalloproteinases 9 (MMP-9), a wound biomarker upregulated in non-healing wounds. Concentration-dependent measurements performed with wound fluid spiked with MMP-9 on GFET-MMP/PEG sensors exhibited real-time detection of MMP-9 with a detection limit of 96 pM in 1x MOPS/1 mM CaCl 2. The sensor was tested on swab samples from non-healing wounds and compared to results of antibody-based ELISA analysis. In contrast to ELISA, the GFET sensor was only sensing the active MMP-9 form and not the mixture of active and inactive forms, as evidenced by the analysis performed in the presence of EDTA as inactivation medium.