Activatable Nanoreporters for Real-Time Tracking of Macrophage Phenotypic States Associated with Disease Progression.

Diagnosis of inflammatory diseases is characterized by identifying symptoms, biomarkers, and imaging. However, conventional techniques lack the sensitivities and specificities to detect disease early. Here, it is demonstrated that the detection of macrophage phenotypes, from inflammatory M1 to alternatively activated M2 macrophages, corresponding to the disease state can be used to predict the prognosis of various diseases. Activatable nanoreporters that can longitudinally detect the presence of the enzyme Arginase 1, a hallmark of M2 macrophages, and nitric oxide, a hallmark of M1 macrophages are engineered, in real-time. Specifically, an M2 nanoreporter enables the early imaging of the progression of breast cancer as predicted by selectively detecting M2 macrophages in tumors. The M1 nanoreporter enables real-time imaging of the subcutaneous inflammatory response that rises from a local lipopolysccharide (LPS) administration. Finally, the M1-M2 dual nanoreporter is evaluated in a muscle injury model, where an initial inflammatory response is monitored by imaging M1 macrophages at the site of inflammation, followed by a resolution phase monitored by the imaging of infiltrated M2 macrophages involved in matrix regeneration and wound healing. It is anticipated that this set of macrophage nanoreporters may be utilized for early diagnosis and longitudinal monitoring of inflammatory responses in various disease models.

Size-Transformable Superoxide-Triggered Nanoreporters for Crosstalk-Free Dual Fluorescence/Chemiluminescence Imaging and Urinalysis in Living Mice.

Chemiluminescence imaging has been recognized as a valuable tool for ultrasensitive detection of physio-pathological events through elimination of background autofluorescence. However, most chemiluminescent nanoprobes suffer from shallow imaging depths and slow clearance from living bodies, which impede their use in clinical settings. We herein report size-transformable nanoreporters (ADN1 and ADN2) that could be activated at disease site by superoxide anion (O2 ⋅- ) to trigger nanostructure disassembly into renal excretable fluorescent fragments as well as chemiluminescence turn-on for crosstalk-free duplex chemo-fluorescence imaging and in vitro urinalysis. In peritonitis mouse model, we demonstrate that the representative nanoreporter ADN1 spontaneously accumulates at the disrupted peritoneum and is cleaved by upregulated O2 ⋅- to initiate depolymerization and result in red chemiluminescence at 620 nm, enabling sensitive detection of peritonitis at least 19 h earlier than gold standard histological assays. Additionally, the incorporation of a near-infrared (NIR) dye into ADN1 results in ADN2 exhibiting intense and red-shifted chemiluminescence at ≈800 nm, which permits early detection of deeply seated diseases such as drug-induced hepatotoxicity. This study thus showcases a modular design strategy that is not only applicable to developing versatile chemiluminescent nanoprobes with switchable pharmacokinetics for early disease diagnosis, but also promising for future clinical translations.