New Nanotech Tool Developed, Allowing Examination of Single Cells

Scientists at Purdue University have combined an atomic force microscope (AFM) and a nuclear magnetic resonance system to craft the perfect biomedical tool that could reveal cellular secrets not accessible before.

Corey Neu, an assistant professor in Purdue University's Weldon School of Biomedical Engineering, and colleagues have developed this instrument to "see" objects far smaller than possible using light microscopes, ideal for studying molecules, cell membranes, and other biological structures.

An AFM uses a tiny vibrating probe called a cantilever with a tip that travels over the surface of a cell to yield information about materials and surfaces at the scale of nanometers, or billionths of a meter.

However, the AFM doesn't provide information about the biological and chemical properties of cells. So the researchers added a nuclear magnetic resonance detector, using a metal microcoil on the AFM cantilever. An electrical current is passed though the coil, causing it to exchange electromagnetic radiation with protons in molecules within the cell and inducing another current in the coil, which is then detected.

"You could detect many different types of chemical elements, but in this case hydrogen is nice to detect because it's abundant," Neu said. "You could detect carbon, nitrogen and other elements to get more detailed information about specific biochemistry inside a cell." The NMR function can also be added to commercially available AFM probes with minor modifications.

Such an advance makes it possible to perform "mechanobiology" studies to learn how forces exerted on cells influence their behavior. In work focusing on osteoarthritis, their research includes the study of cartilage cells from the knee to learn how they interact with the complex matrix of structures and biochemistry between cells.simultaneously study the mechanical and biochemical behavior of cells, which could provide new insights into disease processes.

Scientists expect that being able to study a cell's internal workings in fine detail would likely yield insights into the physical and biochemical responses to its environment. They say the technology could help them to study individual cancer cells, for example, to uncover mechanisms leading up to cancer metastasis for research and diagnostics.

Paper:

Charilaos Mousoulis et al., Atomic force microscopy-coupled microcoils for cellular-scale nuclear magnetic resonance spectroscopy, Applied Physics Letters, 2013, DOI: 10.1063/1.4801318