Development of a Matrix Metalloproteinase-2 (MMP-2) Biosensing System by Integrating an Enzyme-mediated Color Development Reaction into a Common Electronics Components Setup

Matrix metalloproteinase-2 (MMP-2) is closely related to the proliferation and invasion of various types of cancers. The protease is secreted by malignant tumor cells, thus allowing the enzyme to serve as a biomarker for cancer diagnosis. Methods have been developed to analyze MMP-2 activities; however, their applications to disease diagnosis have not been widely demonstrated yet because of the need for high-end analytical equipment and labor-intensive processes. In this study, we developed an MMP-2 activity assay system by integrating an engineered autoinhibited beta-lactamase which can be activated by MMP-2 in an optical sensing system consisting of reassembled common electronic components, such as a laser diode, a solar cell, and a multimeter. The autoinhibited beta-lactamase was immobilized on a polymeric biosensing channel by a polydopamine coating and self-assembled monolayer methods. In the presence of MMP-2, the immobilized autoinhibited beta-lactamase was converted to an active form that hydrolyzed the chromogenic cephalosporin CENTA, thereby changing the substrate color from pale yellow (lambda(max) = 340 nm) to highly discernible chrome yellow (lambda(max) = 405 nm). By reading the interfered laser-light intensity, we were able to analyze MMP-2 activities precisely both with the samples prepared in a buffer solution and also those in urine. These results suggested that the developed system can be used for the quantitative analysis of enzyme activity related to cancer diagnosis.