Fast and precise localization of ischemic tissues in the myocardium after an acute infarct is required by clinicians as the first step toward accurate and efficient treatment. Nowadays, diagnosis of a heart attack at early times is based on biochemical blood analysis (detection of cardiac enzymes) or by ultrasound‐assisted imaging. Alternative approaches are investigated to overcome the limitations of these classical techniques (time‐consuming procedures or low spatial resolution). As occurs in many other fields of biomedicine, cardiological preclinical imaging can also benefit from the fast development of nanotechnology. Indeed, bio‐functionalized near‐infrared‐emitting nanoparticles are herein used for in vivo imaging of the heart after an acute myocardial infarct. Taking advantage of the superior acquisition speed of near‐infrared fluorescence imaging, and of the efficient selective targeting of the near‐infrared‐emitting nanoparticles, in vivo images of the infarcted heart are obtained only a few minutes after the acute infarction event. This work opens an avenue toward cost‐effective, fast, and accurate in vivo imaging of the ischemic myocardium after an acute infarct.

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Improving clinical techniques for cardiovascular imaging is important for better diagnosis / treatment of cardiovascular diseases, a main cause of mortality in western countries. One problem is a lack of contrast and hence the difficult interpretation of intracoronary images, especially those achieved by optical techniques, such as intracoronary optical coherence tomography (IC‐OCT). This could be overcome by multifunctional contrast agents, leading to better interpretability. In this work, magnetic nanoplatelets are employed to increase the contrast of IC‐OCT images by means of a magnetically modulated approach. This allows high‐resolution visualization of individual macrophages by IC‐OCT, fundamental in the formation of arteriosclerosis plaques. In addition, it is demonstrated that the nanoplatelets and nanoplatelets‐marked‐macrophages can be magnetically driven to specific sites. Thus, the results herein identify magnetic nanoplatelets as unique contrast agents for high‐resolution cardiovascular imaging by optical coherence tomography.

The unique combination of physical and optical properties of silica (core)/gold (shell) nanoparticles (gold nanoshells) makes them especially suitable for biomedicine. Gold Nanoshells have been used from high-resolution in vivo imaging to in vivo photothermal tumor treatment. Furthermore, the reduced size and large scattering cross section of Gold Nanoshells in the second biological window (1000-1700 nm) make them also especially adequate for molecular optical coherence tomography (OCT). In this work, we demonstrate how, after adequate functionalization, gold nanoshells in combination with clinical OCT systems are capable of imaging damage in the myocardium after an infarct. Since both inflammation and apoptosis are two of the main mechanisms underlying myocardial damage after ischemia, such damage imaging is achieved by endowing Gold Nanoshells with selective affinity for the inflammatory marker Intercellular Adhesion Molecule 1 (ICAM-1), and the apoptotic marker phosphatidylserine (PS). The results here presented constitute a first step towards a fast, safe, and accurate diagnosis of damaged tissue within infarcted hearts at the molecular level by means of the highly sensitive OCT interferometric technique.