Preparation and In Vitro Evaluation of a Nano Ultrasound Contrast Agent Targeting Pancreatic Cancer.

To prepare a nano-sized ultrasound contrast agent that specifically targets pancreatic cancer cells and to evaluate its targeting effect In Vitro. PLGA-PEG-NHS was synthesized using PLGA, NHS, and PEG and detected using 1H-NMR. PLGA-PEG-NHS and PFOB were used to prepare PLGA nano contrast agent coated with PFOB by emulsification and volatilization, and then a hedgehog antibody was conjugated. The morphology of the nano contrast agent was observed using a transmission electron microscope, and its particle size and potential were measured using the dynamic light scattering method. The entrapment and drug loading efficiency of the nano contrast agent was measured using gas chromatography-mass spectrometry. The In Vitro release characteristics of the nano contrast agent was measured using the dialysis method. Human pancreatic cancer cell lines SW1990 and CFPAC1 were cultured in medium containing the nano contrast agent. The targeting ability of the nano contrast agent was qualitatively and quantitatively verified using fluorescence microscopy and flow cytometry. The average particle size of the targeted ultrasound contrast agent was 198.9 nm, zeta potential was -31.8 mv, entrapment rate was 63.7±3.9%, drug loading efficiency was 14.3±0.9%, and drug release was 85.3% in 48 h. In Vitro cell experiments showed that the targeted ultrasound contrast agent strongly bound to SW1990 cells with high expression of hedgehog antigen, but no specific binding was detected in CFPAC-1 cells which lack the hedgehog antigen. The nano ultrasound contrast agent prepared by emulsification and volatilization method can be potentially used for the diagnosis of pancreatic cancer.

A diselenide bond-containing ROS-responsive ruthenium nanoplatform delivers nerve growth factor for Alzheimer's disease management by repairing and promoting neuron regeneration.

Alzheimer's disease (AD) is an incurable neurodegenerative disease. Repairing damaged nerves and promoting nerve regeneration are key ways to relieve AD symptoms. However, due to the lack of effective strategies to deliver nerve growth factor (NGF) to the brain, achieving neuron regeneration is a major challenge for curing AD. Herein, a ROS-responsive ruthenium nanoplatform (R@NGF-Se-Se-Ru) drug delivery system for AD management by promoting neuron regeneration and Aß clearance was investigated. Under near-infrared (NIR) irradiation, nanoclusters have good photothermal properties, which can effectively inhibit the aggregation of Aß and disaggregate Aß fibrils. Interestingly, the diselenide bond in the nanoclusters is broken, and the nanoclusters are degraded into small ruthenium nanoparticles in the high reactive oxygen species (ROS) environment of the diseased area. Besides, NGF can promote neuronal regeneration and repair damaged nerves. Furthermore, R@NGF-Se-Se-Ru efficiently crosses the blood-brain barrier (BBB) owing to the covalently grafted target peptides of RVG (R). In vivo studies demonstrate that R@NGF-Se-Se-Ru nanoclusters decrease Aß deposits, inhibit Aß-induced cytotoxicity, and promote neurite outgrowth. The study confirms that promoting both Aß clearance and neuron regeneration is an important therapeutic target for anti-AD drugs and provides a novel insight for AD therapy.