Ultrasound Contrast Agents /polypyrrole Nanoshell For Theranostic Integration

Nowadays, cancer has been one of the most deadly diseases. Compared to traditional therapies such as operation treatment, radiotherapy and chemotherapy, photothermal therapy is a new-style treatment method. It can convert the light energy into thermal energy under the help of photothermal transit ion reagents to raise the temperature of tumour cells and kill them. In the filed of cancer diagnosis, there are many imaging modalit ies, such as ultrasonic imaging(US), positron emission tomography(PET) and magnetic resonance imaging(MRI) etc. Different types of imaging modalities have their own advantages and disadvantages. Combining two or more kinds of modalit ies together can avoid the disadvantages of single imaging technique, making therapy more accurate. Furthermore, if diagnostic agents and therapeutic agents can be mixed to be a single agent called a theraonostic agent, it is possible to accomplish the tumor diagnose and therapy simultaneously. Therefore, it takes less time in the process of treatment and increases the efficiency which can ease the patients’ pain throughout the whole process.This article prepared a multifuntina l micromubble(MB) via a double-emusion procedure, which intergrated US imaging, MRI and photothermal therapy multifunctions, by coating polypyrrole nanoshells onto the surface of PLA MBs or Fe3O4-embeded PLA MBs. The results showed that the both two molecules are between 2-5 μm in size which meets the clinical size requirement of the contrast agents. The photothermal experiments demonstrated that the mult ifuntional theranostic MBs could convert light energy into heat energy efficiently under the irradiation of near- infrared light. C ytotoxicity experimental results displayed tha t these molecules had almost no toxic effect to HUVEC cells. Moreover, the PLA-PPy MBs and Fe3O4-PLA-PPy MBs exhibited favorable US imaging in vitro and in vivo and MRI in vitro abilities, respectively.All of the results showed that PLA-PPy MBs had the advantage of enhancing the effect of photothermal and ultrasonic imaging and photothermal therapy, US imaging and MRI for Fe3O4-PLA-PPy MBs. The combination of these two kinds of molecules makes it possible to diagnose and kill tumor cells at the same time and stimulates the broad research interest in this promising emerging field.