Study on the in vitro targeting and imaging performance of aptamer modified targeted ultrasound/photoacoustic dual-modality contrast agent

Abstract

Objective To study the targeting ability of aptamer-modified PLGA nanoparticle encapsulated with gold nanorod and liquid perflurocarbon, and observe its mediated ultrasound/photoacoustic dual-modality imaging in vitro. Methods PLGA nanoparticle was prepared using double emulsion technique. Aptamer-modified PLGA nanoparticle was obtained by connecting, then PLGA nanoparticle was conjugated with MUC1 aptamer carbodiimide technique aimed to obtain aptamer-modified PLGA nanoparticle.Targeting ability of aptamer-modified PLGA nanoparticle to MCF-7 tumor cells in vitro was tested by fluorescence microscope. Besides, there were three control groups including PLGA nanoparticle group, aptamer group and HELA cell group. A commercial photoacoustic instrument was used to detect ultrasound/photoacoustic signal. Results A significant number of aptamer-modified PLGA nanoparticles gathered around the MCF-7 cells, however, the specific binding can not be observed in control groups. Both ultrasound and photoacoustic signal intensity of the aptamer-modified PLGA nanoparticles increased significantly when excited with laser. Conclusions The aptamer-modified PLGA nanoparticle was successfully prepared, and had superior targeting ability to MCF-7 cells, Morever, ultrasound/photoacoustic signal emitted the by nanoparticle increased significantly.These properties make the targeted nanoparticle a great potential to become a distinguished ultrasound/photoacoustic dual modality contrast agent, which lays good foundation for further targeted imaging application in vivo. Key words: Ultrasonography; Photoacoustic imaging; Aptamers, nucleotide; Nanoparticles