Aqueous zymography screening of matrix metalloproteinase activity and inhibition based on colorimetric gold nanoparticles

An optical gold nanoparticles (AuNPs)-based method was fabricated for the rapid detection of matrix metalloproteinase (MMP) activity and screening potential MMP inhibitors without sophisticated instruments. The diagnosis platform was composed of AuNPs, particular MMP substrates and 6-mercapto-1-hexanol (MCH). The functionalized AuNPs were subjected to specific MMP digestion, and the MMP found the substrate on AuNPs, such that the AuNPs lost shelter and MCH increased the attraction force between AuNPs. Consequently, AuNPs aggregation and a color change from red to purple with increasing MMP concentration were observed. The surface plasmon resonance (SPR) of the formed AuNPs allowed for the quantitative detection of MMP activity. A sensitive linear correlation existed between the absorbance and the activity of the MMPs, which ranged from 10ng/mL to 700ng/mL in NTTC buffer and plasma samples. The proposed colorimetric method could be accomplished in a homogeneous solution with one-step operation in 30min and has been successfully applied to the determination of particular MMP activity in plasma samples, in which the results are consistent with substrate zymography. This technology may become a simple platform for parallel screening a number of inhibitors and offer an alternative method to studying the efficiency of inhibitors for suppressing MMP activity. The absorbance ratio at 625nm and 525nm (A ₆₂₅ /A ₅₂₅ ) confirmed the efficiency of the inhibitors as observed in substrate zymography. The IC ₅₀ of ONO-4817 and galardin for MMP-1, MMP-2 and MMP-7 determined by the proposed colorimetric method was similar to the results of substrate zymography.