Fabrication and characterization of bioprobe integrated with a hollow nanoneedle for novel AFM applications in cellular function analysis

[Display omitted] ► We propose a newly designed AFM probe for cellular function analysis. ► We demonstrate the ability of the bioprobe to capture AFM images of living cells. ► The hollow nanoneedle tip can penetrate the cell membrane without cell damage. ► We propose a novel intracellular delivery method based on electrokinetic flow. In order to realize spatial and temporal imaging of cellular functions of single living cells, we have been developing a newly designed probe for an atomic force microscope (AFM) we call a “bioprobe”, which is integrated with a hollow silicon dioxide (SiO2) nanoneedle. The bioprobe can be used to take AFM measurements, introduce desired biomolecules (DNA, proteins, etc.) into living cells, and extract target biomolecules expressed inside the cells. In this paper, we demonstrate the ability of the fabricated bioprobe to capture AFM images of living HeLa cells under near-physiological conditions. The sharp-tipped SiO2 nanoneedle can be inserted into cells without causing significant cell damage. We also propose a novel intracellular delivery method based on electrokinetically driven flow. Preliminary ejection tests revealed its capability of handling an extremely small volume of liquid with a nanoneedle tip having good controllability.