A SERS and fluorescence dual mode cancer cell targeting probe based on silica coated Au@Ag core-shell nanorods

► A metal-organic-QD hybrid nanoprobe is synthesized for cancer cell targeting. ► Its SERS and fluorescence can be switched by changing the exciting wavelength. ► It is advantageous for multi-component tracking due to QD's narrow emission bands. ► Au@Ag nanorods exhibit much stronger SERS enhancement than Au nanorods. ► It can target cancer cells with overexpressed folate receptors by two mode images.