A graphene oxide platform for energy transfer-based detection of protease activity

In this article, we report the first graphene oxide (GO)-based platform to detect protease activity in a homogeneous real-time format. In designing such GO-based biosensing platform, we put a protease substrate peptide as the linker between the energy transfer donor (QDs) and the energy transfer acceptor (GO) to fabricate the GO-peptide-QDs nanoprobes. In the nanoprobes, the photoluminescence (PL) of donor QDs was strongly quenched due to the presence of GO in close proximity. The protease activity caused modulation in the efficiency of the energy transfer between the acceptor and donor, thus enabling the protease assay. The proposed GO-based platform is easy to assemble and has little background interference, yet still give superior sensitivity and rapid response. Furthermore, this GO-QDs architecture can serve as a universal platform by simply changing the types of peptide sequences for the different proteases. In this work, GO-based platform has been successfully applied in the sensitive detection of matrix metalloproteinase (MMP) and thrombin activity. Meanwhile, we also utilized this platform to monitor the protease inhibitor. The proposed GO-based platform is anticipated to find applications in the diagnosis of protease-related diseases and screening of potential drugs with high sensitivity in a high-throughput way.