Theranostics 2018; 8(11):3111-3125. doi:10.7150/thno.24613 This issue

Research Paper

Dual-functional protein for one-step production of a soluble and targeted fluorescent dye

Yunjie Xiao1,*, Qian Zhang2,*, Yanyan Wang3,*, Bin Wang1, Fengnan Sun2, Ziyu Han3, Yaqing Feng4, Haitao Yang1,5, Shuxian Meng2✉, Zefang Wang1✉

1. School of Life Sciences, Tianjin University, Tianjin 300072, China.
2. School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China.
3. College of Precision Instrument and Opto-electronics Engineering, Tianjin University, Tianjin 300072, China.
4. Collaborative Innovation Center of Chemical Science and Engineering, Tianjin University, Tianjin 300072, China.
5. Tianjin International Joint Academy of Biotechnology and Medicine, Tianjin 300457, China.
* These authors contributed equally to this work.

This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY-NC) license ( See for full terms and conditions.
Xiao Y, Zhang Q, Wang Y, Wang B, Sun F, Han Z, Feng Y, Yang H, Meng S, Wang Z. Dual-functional protein for one-step production of a soluble and targeted fluorescent dye. Theranostics 2018; 8(11):3111-3125. doi:10.7150/thno.24613. Available from

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Graphic abstract

Low water solubility and poor selectivity are two fundamental limitations that compromise applications of near-infrared (NIR) fluorescent probes.

Methods: Here, a simple strategy that can resolve these problems simultaneously was developed by using a novel hybrid protein named RGD-HFBI that is produced by fusion of hydrophobin HFBI and arginine-glycine-aspartic acid (RGD) peptide. This unique hybrid protein inherits self-assembly and targeting functions from HFBI and RGD peptide respectively.

Results: Boron-dipyrromethene (BODIPY) used as a model NIR dye can be efficiently dispersed in the RGD-HFBI solution by simple mixing and sonication for 30 min. The data shows that self-assembled RGD-HFBI forms a protein nanocage by using the BODIPY as the assembly template. Cell uptake assay proves that RGD-HFBI/BODIPY can efficiently stain αvβ3 integrin-positive cancer cells. Finally, in vivo affinity tests fully demonstrate that the soluble RGD-HFBI/BODIPY complex selectively targets and labels tumor sites of tumor-bearing mice due to the high selectivity of the RGD peptide.

Conclusion: Our one-step strategy using dual-functional RGD-HFBI opens a novel route to generate soluble and targeted NIR fluorescent dyes in a very simple and efficient way and may be developed as a general strategy to broaden their applications.

Keywords: NIR fluorescent probes, RGD peptide, self-assembly, protein nanocage