Inflammation-targeted gold nanorods for intravascular photoacoustic imaging detection of matrix metalloproteinase-2 (MMP 2 ) in atherosclerotic plaques

Elevated expression of matrix metalloproteinase-2 (MMP2) is one of the clinical features of high-risk atherosclerotic plaques. Many methods such as fluorescence imaging methods have been used to detect MMP2 for evaluating plaque vulnerability. However, so far no imaging method has been able to resolve the expression of MMP2 with high fidelity and resolution beyond microscopic depths. In this study, gold nanorods conjugated with MMP2 antibody (AuNRs-Abs) were developed as a highly efficient photoacoustic imaging (PAI) probe for mapping MMP2 in atherosclerotic plaques. AuNRs-Abs could specifically target MMP2 as demonstrated by scanning electron microscope and immunofluorescence imaging. After labeling with AuNRs-Abs, area of distribution of MMP2 from the surface to the depths of the atherosclerotic plaques was revealed using intravascular PAI. AuNRs-Abs has the ability to enable quantitative detection of MMP2 in atherosclerotic plaques.