OFF/ON galvanic replacement reaction for preparing divergent AuAg nano-hollows as a SERS-visualized drug delivery system in targeted photodynamic therapyElectronic supplementary information (ESI) available. See DOI: 10.1039/c6ra12971d

A polymer-inhibition (off) and proton-triggered (on) galvanic replacement reaction was developed for preparing divergent growth of the core-free AuAg nanoparticles. We demonstrated an excellent surface plasmon resonance behavior and surface-enhanced Raman scattering (SERS) of 3-D AuAg nano-hollows for potential SERS sensor as well as Raman imaging-guided and folic acid-targeted photodynamic therapy of cancer cells. 3-D AuAg nano-hollows were fabricated by an anti-galvanic replacement reaction (off), followed by a proton exchange reaction (on). They exhibited superior Raman detection sensitivity for potentially imaging-guided and folic acid-targeted photodynamic therapy of cancer cells.