In vitro study of a pH-sensitive multifunctional doxorubicin-gold nanoparticle system: therapeutic effect and surface enhanced Raman scattering

We report the development and characterization of a multifunctional drug delivery system (Au-dox-PEG) for the treatment and SERS spectroscopic detection of tumors. Doxorubicin, a therapeutic agent and a SERS tag, was chemically conjugated to gold nanoparticles via a pH-sensitive hydrazone linker, and then PEG was added to develop Au-dox-PEG. The doxorubicin occupied a maximum of 20% of the total surface area of the gold nanoparticles which resulted in colloidal stability. SERS spectra were measured for non-aggregated Au-dox-PEG using near-infrared wavelength radiation, and the doxorubicin release was time and pH dependent. Consistency in the release profile and in vitro cell viability results supports the efficacy of the Au-dox-PEG system. Thus, the development of the Au-dox-PEG multifunctional system raises exciting opportunities for the simultaneous spectroscopic detection and therapy of tumors in the future.