Stable aqueous ZnO@polymer core-shell nanoparticles with tunable photoluminescence and their application in cell imaging.

Stable aqueous solutions of ZnO@polymer core-shell nanoparticles with tunable photoluminescence are prepared through a simple sol-gel route. The copolymer shell has many hydrophilic external groups and a hydrophobic internal layer which connects ZnO cores through covalent bonds. The optimal samples show quantum yield above 50% and stable emission for months. These samples with their concentrations of below 0.2 mg/mL are nontoxic to human cells. After uptake of these ZnO@polymer nanoparticles, the luminescent cells have enough life under UV light for microscopic imaging.