Study On The Preparation Of A Polymer Microbubble Contrast Agent

This paper reviewed the history of polymeric microbubble contrast agents, studied the composition and preparation of microbubble contrast agents. We proposed a special polymeric microbubble contrast agents preparation method: emulsion polymerization that is different from tradition methods: neutralization, adsorption, mechanical stirring method , sonication , freeze-drying method and hydrating method. Polymeric microbubble contrast agents are not only widely used in the ultrasonic medical field, but also used in drug or gene delivery.Polymeric microbubble contrast agents which prepared in former experiment have many problems, such as low monomer rate, thrill odor, poor developing properties and so on. Biodegradation and drug or gene delivery of microbubble still is a new concept.At first, we solved these problems: labilization, toxicity and thrill odor of microbubbles. Besides change the species and dosage of monomer, emulsifier and initiator, which are necessary in the reaction, reaction time, biodegradability and preserving times were also investigated respectively.Secondly, we use three methods to reflect developing properties of the polymer contrast agents whose diameter was observed by microscope. By comparison to other methods, a good vitro experiment-agar method was found. The value of PCD and COD, infrared spectrogram for acrylic polymer were recommended to evaluate biodegradability of acrylic polymer.At last, we validated the developing properties and security of acrylic polymer by animal trial and observed ability of gene delivery though combining microbubbles with DNA.The best reaction condition and species of monomer which used in its stomach were confirmed. The average diameter of microbubbles was between 0.5μm and 4μm, the concentration was 10~9/mL, and can keep more than 10 months. Animal trial and vitro experiments showed that rat imaging contrast was obviously enhanced agent in itsstomach by said contrast. Moreover, the self-designed polymeric microbubbles contrast agent can be combined with DNA fractions in 30 minutes. High-velocity centrifugal effect does not change the combination.