Facile synthesis of thiol and alkynyl contained SERS reporter molecular and its usage in assembly of polydopamine protected bioorthogonal SERS tag for live cell imaging.

A bioorthogonal Raman reporter-embedded Au-core and polydopamine-shell nanoprobe was initially designed and synthesized for live cell surface-enhanced Raman scattering (SERS) imaging in Raman-silent region. The firstly synthetic bioorthogonal Raman reporter (E)-2- ((4-(phenylethynyl) benzylidene)amino)ethanethiol (PBAT) provided intense Raman signal at 2220cm(-1) in Raman-silent region. And its synthetic method was environmentally benign, high yield and easy in operation. In addition, the hydrophobicity of PBAT led to slightly aggregation of gold nanoparticles, which enhance the SERS intensity of the nanoprobe through hot spots. Furthermore, owing to the remarkable biocompatibility of polydopamine (PDA), the SERS nanoprobe can be smoothly internalized into cancer cells to realize SERS imaging in Raman-silent region. Finally, the SERS mapping results confirmed that nanoprobe exhibited strong SERS signal intensity, excellent stability in complex biological environment and low toxicity inside live cancer cells. Therefore, the reporter-embedded core-shell nanoprobe has enormous potential of applications in biomedical diagnostics in the near future.