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

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