LIFU-responsive nanomedicine enables acoustic droplet vaporization-induced apoptosis of macrophages for stabilizing vulnerable atherosclerotic plaques

Due to the high risk of tearing and rupture,vulnerable atherosclerotic plaques would induce serious cardiovascular and cerebrovascular diseases.Despite the available clinical methods can evaluate the vulnerability of plaques and specifically treat vulnerable plaques before a cardiovascular event,but the efficiency is still low and undesirable.Herein,we rationally design and engineer the low-intensity focused ultrasound(LIFU)-responsive FPD@CD nanomedicine for the highly efficient treatment of vulnerable plaques by facilely loading phase transition agent perfluorohexane(PFH)into biocompatible PLGA-PEG-PLGA nanoparticles(PPP NPs)and then attaching dextran sulphate(DS)onto the surface of PPP NPs for targeting delivery.DS,as a typical macrophages-targeted molecule,can achieve the precise vaporization of NPs and subsequently controllable apoptosis of RAW 264.7 macrophages as induced by acoustic droplet vaporization(ADV)effect.In addition,the introduction of DiR and Fe3O4 endows nanomedicine with near-infrared fluorescence(NIRF)and magnetic resonance(MR)imaging capabilities.The engineered FPD@CD nanomedicine that uses macrophages as therapeutic targets achieve the conspicuous therapeutic effect of shrinking vulnerable plaques based on in vivo and in vitro evaluation outcomes.A reduction of 49.4%of vascular stenosis degree in gross pathology specimens were achieved throughout the treatment period.This specific,efficient and biosafe treatment modality potentiates the biomedical application in patients with cardiovascular and cerebrovascular diseases based on the relief of the plaque rupture concerns.

Liquid vaporization under thermodynamic phase non-equilibrium condition at the gas-liquid interface

Liquid vaporization under thermodynamic phase non-equilibrium condition at the gas-liquid interface is investigated over a wide range of fluid state typical of many liquid-fueled energy conversion systems. The validity of the phase-equilibrium assumption commonly used in the existing study of liquid vaporization is examined using molecular dynamics theories. The interfacial mass flow rates on both sides of the liquid surface are compared to the net vaporization rate through an order-of-magnitude analysis.Results indicated that the phase-equilibrium assumption holds valid at relatively high pressures and low temperatures,and for droplets with relatively large initial diameters(for example,larger than 10 μm for vaporizing oxygen droplets in gaseous hydrogen in the pressure range from 10 atm to the oxygen critical state). Droplet vaporization under superheated conditions is also explored using classical binary homogeneous nucleation theory,in conjunction with a real-fluid equation of state. It is found that the bubble nucleation rate is very sensitive to changes in saturation ratio and pressure;it increases by several orders of magnitude when either the saturation ratio or the pressure is slightly increased. The kinetic limit of saturation ratio decreases with increasing pressure,leading to reduced difference between saturation and superheat conditions. As a result,the influence of nonequilibrium conditions on droplet vaporization is lower at a higher pressure.