On chip manipulation of carbon dots via gigahertz acoustic streaming for enhanced bioimaging and biosensing

Currently, researches on nanomaterials have been restricted by slow and multistep synthesis procedures. Herein, we demonstrate an ultrafast, one step method of purification and delivery of quantum dots into living cells, actuated by the acoustic streaming (AS) produced through a gigahertz resonator. Results demonstrate that the impurities in the carbon dots (CDs) can be extracted immediately aided by the acoustic forcing, with extra high purification efficiency of 93%. The system can also efficiently deliver the CDs into cells, showing excellent nucleus and mitochondria uptake under 3 min of AS treatment, and making the organelles of cells to be recorded more easily and simultaneously. More importantly, the AS is found to further accelerate the bioreaction inside the cells, thus realizes the enhanced biosensing of Fe³⁺ in single living cells. This work develops a novel type of multifunctional method for effective purification, intracellular delivery and biosensing of nanomaterials, inspiring the biological/medical nanotechnology researches at subcellular level.