Nanobubbles: A Novel Targeted Drug Delivery System

Abstract Nanobubbles are nanometer size bubbles having different constituents of varying physicochemical characteristic for the inner core and outer shell. Nanobubbles are mainly fabricated to improve the stability, bioavailability and improve the biodistribution of the delivered drug to the specific targeted site. Their small sizes bubbles allow the possibility of extravasation from blood vessels into the surrounding tissues and ultrasound-targeted site-specific release with minimal invasiveness. Nanobubbles are developing as important contrast agents for imaging and carriers for drug delivery at targeted region. Sonication is the primary method for preparation of nanobubbles followed by thin-layer evaporation, high shear emulsification, mechanical agitation and coacervation or coalescence. With exposure to ultrasound/extracorporeal shock waves, the drug is liberated from the nanobubbles into the target cells. This review paper is an effort to reveal the different formulation development techniques briefly and varying shell and core content for developing nanobubbles.

Precise nano-targeted technology based on disease microenvironment targeting / 医学研究生学报

Research into the rational delivery and targeting of pharmaceutical, therapeutic, and diagnostic agents is at the forefront of projects in nanomedicine with the launch of ‘precision medicine’, and into the era of ‘precise’ targeted nano drug delivery system design. According to the lesion feature of disease endangering human health, it is one of the important strategies to design nano drug delivery system that targets each of the lesions which could change the distribution of drugs in the body, specifically increasing the concentration of drugs in the target sites and reducing the concentration of non-target sites, so as to enhance the efficacy, reduce adverse reactions and achieve precise nano-targeted treatment of diseases.at last. This article introduces the design principle and latest research progress of drug passive and active nano targeting delivery of drugs based on local microenvironment characteristics of lesions in tumors, atherosclerosis, inflammatory diseases in recent years, aiming to provide reference and basis for the design of more nano-targeted drug delivery systems for tumors and other diseases.

Mechanical analysis of the single microparticle motion in blood vessel / 医用生物力学

Objective To analyze the force condition of a single microparticle in blood vessel and the factors that influencing its motion. Method The microparticles in blood vessel during targeted drug delivery were studied, and the fluid flow in blood vessel was simplified as the Poiseuille flow in parallel plate flow chamber. Specific methods for calculating each force subjected on the single microparticle in the flow field were analyzed. The motion equations of the single microparticle were determined through calculation of its force balance and torque balance. The relationship between the force subjected on the single microparticle and the particle diameter/flow rate as well as the critical motion conditions of the particle diameter and flow rate were obtained by numerical calculation. Results The single microparticle was more subjected to the motion of rolling, sliding and ascending with the increase of flow rate and particle diameter. In flow rate and particle diameter diagrams, the critical curve of ascending motion located above that of sliding motion, while the rolling curve was located at the bottom.Conclusions The microparticle will not do the ascending motion under the condition of blood flow rate in human. As the blood flow rate reduces, the motion of microparticle with given diameter will be transfered from sliding to rolling, and will be entirely still under the condition of elastic deformation. Therefore, the proper selection of mircoparticle diameter and its surface adhesivity is critical for the drug particle to transport to the target location.