New surface-modified zinc oxide nanoparticles with aminotriethylene oxide chains linked by 1,2,3-triazole ring: Preparation, and visible light-emitting and noncytotoxic properties

► Surface-modified ZnO NPs (ZPAZ) with aminotriethylene oxide chains linked by 1,4- and/or 1,5-disubstituted 1,2,3-triazole rings were prepared via azide/alkyne click reaction by heating without Cu(I) catalyst. ► The resulting ZPAZ particles had nanostructured sizes below 6 nm and showed a broad visible emission band due to trapped-electron emission. ► It was demonstrated that the ZPAZ NPs are noncytotoxic and almost all RAW264.7 cells are alive after 24 h of treatment. ► The application of ZPAZ NPs to biological imaging and labeling probes will pave the way to develop novel diagnostic strategies for intractable diseases.