Ag2S nanodots have already been demonstrated as promising near-infrared (NIR-II, 1.0-1.45 μm) emitting nanoprobes with low toxicity, high penetration and high resolution for in vivo imaging of, for example, tumors and vasculature. In this work, we have systematically investigated the potential application of functionalized Ag2S nanodots for accurate imaging of damaged myocardium tissues after a myocardial infarction induced by either partial or global ischemia. Ag2S nanodots surface-functionalized with the angiotensin II peptide (ATII) have shown over 10-fold enhanced binding efficiency to Nano ResearchDOI (automatically inserted by the publisher)

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.

Neodymium-doped yttrium aluminum garnet (YAG:Nd 3+ ) has been widely developed during roughly the last sixty years and has been an outstanding fluorescent material.It has been considered as the gold standard among multipurpose solid-state lasers. Yet, the successful downsizing of this system into the nano regimen has been elusive, so far. Indeed, the synthesis of a garnet structure at the nanoscale, with enough crystalline quality for optical applications was found to be quite challenging. Here, we present an improved solvothermal synthesis method producing YAG:Nd 3+ nanocrystals of remarkably good structural quality.Adequate surface functionalization using asymmetric double-hydrophilic block copolymers, constituted of a metal-binding block and a neutral water soluble block, provides stabilized YAG:Nd 3+ nanocrystals with a long term colloidal stability in aqueous suspensions. These newly stabilized nanoprobes keep the spectroscopic quality (long lifetimes, narrow emission lines, and large Stokes shift) characteristic of bulk YAG:Nd 3+ . The narrow emission lines of YAG:Nd 3+ nanocrystals are exploited by differential infrared fluorescence imaging, thus achieving an autofluorescence-free in vivo readout. In addition, nanothermometry measurements, based on the ratiometric fluorescence of the stabilized YAG:Nd 3+ nanocrystals, are demonstrated. The progress here reported paves the way for the implementation of this new stabilized YAG:Nd 3+ system in the preclinical arena.

Amphiphilic conjugated polymer was designed and utilized as nanocarriers without further general encapsulation using PEGylated materials for photothermal therapy (PTT) and chemotherapy. These nanocarriers have maximum absorption in ideal phototherapeutic window between 800 and 850 nm and excellent photothermal conversion efficiency of 76% at 808 nm. It provides the simultaneous therapy of chemotherapy and PTT with the monitoring of photoacoustic imaging. After combined therapy via tail vein injection, complete remission and no recurrence of tumors can be observed over a course of 20 days, indicating these amphiphilic NPs has great potential for NIR photoacoustic imaging-guided photothermal and chemo combined therapy.