Research About Preparation Of Ultrasound Contrast Agents That Have Therapeutical Effect By Microfluidic Focusing

It has been shown that ultrasound microbubble contrast agents can be used as carrier of gene and drug due to its cavitation’s effect. It can improve drug and gene transportation efficiency and expression in cells. Ultrasound contrast agents with therapeutical effect can be used to diagnose and treatment of diseases at the same time. The dimensions and uniformity of microbubbles are the important factors that used to evaluate the performance of ultrasound microbubble contrast agents. The microchannels were designed and fabricated. Microbubbles that can carry gene or drug were prepared by microfluidic focusing. The factors such as the liquid flow rate and the gas pressure that influence the formation of microbubbles were studied. The results showed that the microchannels made from PDMS can be made by photolithography and in-situ reaction molding. Microbubbles that can be used as carrier of gene or drug consist of the core, the middle layer and shell layer. They were prepared by the microchannels by the capillary instability effect and restraint of shape. The liquid flow rate and the gas pressure influence the formation of microbubbles. The flow rate of the liquid in the middle layer was adjusted. The relationship of the liquid flow rate and dimension of microbubbles is not monotone. There is a liquid flow rate that dimensions of microbubbles are symmetric. With the increase of the gas pressure, the dimension of microbubbles decreased. The ultrasound effect of microbubbles carrying genes prepared by agitation was studied in vitro.