Small endoscope without lenses captures 3D images of objects smaller than a cell

A self-calibrating endoscope that can produce 3D images of objects is the device created by a group of researchers at the Technical University of Dresden.

The endoscope is capable of producing images of objects smaller than a single cell and without using lenses or optical, mechanical or electrical components. With its 200 micron wide tip, this new instrument could be particularly useful for imaging within living tissue. However, the very small and thin tip, essentially the size of a needle, could allow a variety of applications not only in medicine but in research in general.

Traditional endoscopes use small cameras or light (via optical fibres) to acquire images from inside the body. It is the fiber that allows the use of very thin and small endoscopes that can therefore creep into more places.

However, these devices require quite complicated calibration processes just as the fiber collects the images. The researchers at the German institute have solved this problem by adding a very thin glass plate, which is only 150 microns thick, at the tip of a small bundle of consistent fibres.

Consistent fibers are optical fibers commonly used in endoscopy applications. The beam of those used for this new device is about 350 microns wide. When the core of the fiber is illuminated, a beam is emitted which is then reflected and can be used to measure how light is transmitted.

This function, called optical transfer, then provides the data to represent the 3D images. This new approach “allows both real-time calibration and minimally invasive imaging, which is important for in situ 3D imaging, lab-on-a-chip manipulation of mechanical cells and deep tissue optogenics in vivo,” says Czarske.

As Juergen W. Czarske, one of the researchers involved in the project, explains, this endoscope can have “minimally invasive” access as well as producing high contrast images.

Regarding possible uses, Czarske himself says: “The endoscope is likely to be particularly useful for optogenetics – research approaches that use light to stimulate cellular activity. It could also be useful for monitoring cells and tissues during medical procedures, as well as for technical inspections.”