BioAFM Resource Library

Investigation of Living Cells Using QI Mode

Learn about the benefits of quantitative imaging when investigating challenging biological samples


KEYWORDS: Atomic Force Microscopy; AFM; NanoWizard; Quantitative Imaging; QI; QI Mode; Force Curves; Cell Biology; Live Cell Imaging; Life Science

Although many adaptations and modes have been developed over the years, live cell imaging and characterization using atomic force microscopy (AFM) have remained challenging and reserved for experienced AFM specialists. Successful measurement needed a good understanding of the technique and also particular care because of the high features and soft surface of living cells. Imaging under physiological conditions can also contribute to thermal drift of the cantilever and bending due to absorbed molecules. These factors made it difficult to maintain low imaging forces and obtain images reflecting the actual surface of the cell.

Bruker recently launched its new QI (Quantitative Imaging) mode, a solution which makes imaging challenging samples much easier and possible for all users. QI mode takes a force curve at every pixel using a unique tip movement algorithm and has two main benefits. First, very delicate samples, such as living cells, can be imaged without lateral forced. Second, the resulting data are much more versatile than just a few images. Each image pixel contains a force-distance curve which can be analyzed to determine various values, like the adhesion force, contact point, or Young’s modulus. Presented here is the use of Bruker's new QI mode for the investigation of living cells. The principle of this imaging mode is explained and different applications and the benefits for live cell studies are discussed.

Readers can expect to learn about:

  • The principle of force-curved based quantitative imaging and the benefits compared to other AFM imaging modes ;
  • Prominent application examples with detailled analysis showcasing the powerful capabilities and easy operation of this imaging mode; and
  • The seamless integration into advanced optical microscopy and the potential of the new QI mode for investigating delicate samples such as living cells.