Targeted Therapy of Atherosclerosis Vulnerable Plaque By ROS-Scavenging Nanoparticles And MR/Fluorescence Dual-Modality Imaging Tracing

Background: Cardiovascular diseases are currently the leading cause of death and disability worldwide, and the key pathological basis is atherosclerosis (AS). Especially, the rupture of vulnerable plaques is the main cause of acute cardiovascular and cerebrovascular events such as myocardial infarction and stroke. Thus, the early identifying and therapy of vulnerable plaques are necessary. Results: In this study, we developed a novel multimodal imaging platform (GPRD) based on Gd doped Prussian blue (GPB) and rhodamine (Rd) to specifically target and identify the vulnerable plaques with the help of dextran sulfate (DS), one of the excellent ligands of scavenger receptor class A (SR-A). It is more important that the nano-enzyme capacity of GPRD NPs realized the elimination of the excessive production of ROS in cells, and the following reduction of ROS-induced oxidative stress, inflammation, apoptosis, and the formation of macrophage-derived foam cells, presenting an inhibition of plaque progress eventually. Conclusions: The ROS-scavenging multimodal imaging nanoprobe provided a new avenue for the diagnosis and treatment of AS vulnerable plaques.

Dual-Modality Imaging Microfluidic Cytometer for Onsite Detection of Phytoplankton

Phytoplankton monitoring is essential for better understanding and mitigation of phytoplankton bloom formation. We present a microfluidic cytometer with two imaging modalities for onsite detection and identification of phytoplankton: a lensless imaging mode for morphological features, and a fluorescence imaging mode for autofluorescence signal of phytoplankton. Both imaging modes are integrated in a microfluidic device with a field of view (FoV) of 3.7 mm × 2.4 mm and a depth of field (DoF) of 0.8 mm. The particles in the water flow channel can be detected and classified with automated image processing algorithms and machine learning models using their morphology and fluorescence features. The performance of the device was demonstrated by measuring Chlamydomonas, Euglena, and non-fluorescent beads in both separate and mixed flow samples. The recall rates for Chlamydomonas and Euglena ware 93.6% and 94.4%. The dual-modality imaging approach enabled observing both morphology and fluorescence features with a large DoF and FoV which contribute to high-throughput analysis. Moreover, this imaging flow cytometer platform is portable, low-cost, and shows potential in the onsite phytoplankton monitoring.

Revealing the Distribution of Aggregation-Induced Emission Nanoparticles via Dual-Modality Imaging with Fluorescence and Mass Spectrometry

Aggregation-induced emission nanoparticles (AIE NPs) are widely used in the biomedical field. However, understanding the biological process of AIE NPs via fluorescence imaging is challenging because of the strong background and poor penetration depth. Herein, we present a novel dual-modality imaging strategy that combines fluorescence imaging and label-free laser desorption/ionization mass spectrometry imaging (LDI MSI) to map and quantify the biodistribution of AIE NPs (TPAFN-F127 NPs) by monitoring the intrinsic photoluminescence and mass spectrometry signal of the AIE molecule. We discovered that TPAFN-F127 NPs were predominantly distributed in the liver and spleen, and most gradually excreted from the body after 5 days. The accumulation and retention of TPAFN-F127 NPs in tumor sites were also confirmed in a tumor-bearing mouse model. As a proof of concept, the suborgan distribution of TPAFN-F127 NPs in the spleen was visualized by LDI MSI, and the results revealed that TPAFN-F127 NPs were mainly distributed in the red pulp of the spleen with extremely high concentrations within the marginal zone. The in vivo toxicity test demonstrated that TPAFN-F127 NPs are nontoxic for a long-term exposure. This dual-modality imaging strategy provides some insights into the fine distribution of AIE NPs and might also be extended to other polymeric NPs to evaluate their distribution and drug release behaviors in vivo.