Dual-Mode Contrast Agents with RGD-Modified Polymer for Tumour-Targeted US/NIRF Imaging

Zhenhui Nie,1,* Ningbin Luo,1,* Junjie Liu,2 Yu Zhang,1 Xinyi Zeng,1 Danke Su1 1Department of Radiology, Affiliated Tumour Hospital of Guangxi Medical University, Nanning, Guangxi, People’s Republic of China; 2Department of Medical Ultrasound, Affiliated Tumour Hospital of Guangxi Medical University, Nanning, Guangxi, People’s Republic of China*These authors contributed equally to this workCorrespondence: Danke Su Email sudanke@gxmu.edu.cnBackground: Cancer diagnosis and treatment during the early stages of disease remain extremely challenging clinical tasks. The development of effective multimode contrast agents could greatly facilitate the early detection of cancer.Materials and Methods: We prepared dual-mode contrast agents using a biotin/avidin bioamplification system. Through in vivo and in vitro experiments, we verified the imaging performance of this contrast agents in both fluorescence and ultrasound and its targeting specificity for MDA-MB-231 cells.Results: The RGD peptide-labelled microbubbles showed excellent targeting of αvβ 3 integrin expressed by MDA-MB-231 cells in vitro and in vivo. The signal intensity and time duration of ultrasound imaging using these particles were superior to those obtained with a typical ultrasound contrast agent in the clinic. The tumour areas also demonstrated high Cy5.5 accumulation by fluorescence imaging.Conclusion: The results show that this targeted dual-mode imaging system yields outstanding US/NIRF imaging results, possibly allowing the early clinical diagnosis of cancer.Keywords: ultrasound, molecular imaging, microbubble, targeting imaging