Organic Material With Near-infrared Absorption For The Application Of Photoacoustic Imaging

In the past few decades, due to the normal imaging mode can not able to meet people’s needs,photoacoustic imaging has become the focus of attention of researchers. In order to achieve the target of biological tissue, and further improve the photoacoustic imaging signal, we need to introduce an exogenous molecular probes. After years of efforts,the scientists develop a targeting photoacoustic probe with strong near-infrared absorption, such as gold, silver, copper and other metal nanoparticles and carbon nanotubes. However, due to the toxicity of inorganic nanomaterials,we need further modification. Because of the organism has a biological tissue similar molecules, we developed the organic material in the photoacoustic imaging, but also easy to molecular modification. For this paper we have made the following studies.(1) We have synthesized a series of near-infrared absorption to perylene diimide as the basic structure of the organic small molecule compounds through a simple and efficient way. According to Professor BASF company Seybold proposed a method to synthesize our target product. The method of synthesis yields general in literature is relatively low, this will reduce the waste of raw materials and raise efficiency of our work. We have to improve on this method by changing the experimental conditions and the introduction of some catalysts can make us yield greatly improved.Then we will go on the photophysical properties of these organic near infrared materials in different solvents, make it possible to achieve near-infrared absorption.(2) Based on our above-mentioned organic near-infrared absorbing material, we carry lecithin package to solve its biological compatibility, and then let it self-assemble into nanoparticles. We carried out the in vivo photoacoustic imaging. The experimental results showed that: the structure of the near-infrared organic material not only has a good biological imaging capabilities and can be a good solution to its toxicity, and in line with animal absorption, ingestion, clear rules, which provide a basis for further application to the human body.(3) We designed and synthesized a new kind of near infrared absorption of water-soluble conjugated polymers M18. We synthesized it by combining different Donor-Accepter structure with near-infrared absorption, and then we modified it branched to solve its water-soluble. We also examined its basic photophysical properties in organic and aqueous, so that it can better use in vivo photoacoustic imaging.