The intestines are an extremely difficult area to navigate through with a medical device. Yet, many people need to have intestinal examinations done to determine if, for example, they have intestinal cancer. The medical device currently used for this is the colonscope, a long, thin and flexible tube that causes patients great discomfort and pain.
For this reason, researchers have been trying to develop alternative medical devices, such as, for example, a small robot that moves independently through the intestinal tract. There is a layer of slime, called mucus, on the inside of the large intestine (colon). The robots, as they move forward under their own power, ignore this layer of mucus and try, if possible, to suck or grab on to the intestinal wall, which results in the walls being stretched and the patient feeling pain and discomfort.
A better method, according to TU Delft researcher Dimitra Dodou, is in fact to use this layer of mucus and allow the robot to imitate the forward movement of a snail. A snail leaves a trail of slime behind it on the ground. This slimy material works simultaneously as a lubricant for gliding on and as a glue which the slug can grip hold of.
An intestinal robot should also have a similar layer to use. To achieve this, an adhesive layer is added to the mucus-like properties, which allows the device to be stuck to the layer of mucus. The ability to be attached to a surface covered with lubricant is a great technological challenge, because most adhesives normally only work on 'clean' surfaces. The researchers discovered a group of polymers, so-called muco-adhesives, that are suitable for this. Dodou used a pig's intestine to evaluate how this material worked. Her findings revealed that muco-adhesives in the form of films provided by far the highest degree of friction.
Despite this, there is nevertheless no possibility of movement. A snail uses the exertions of pressure to change the characteristics of the middle layer, and thus lower the degree of friction, in order to move. In the intestine, however, pressure cannot be exerted, because this would cause the intestine to become deformed. The solution then is found in using smaller and larger surfaces that slide over each other. If a large surface coated with muco-adhesive remains still, and a relatively small surface coated with muco-adhesive begins moving in relation to the larger surface, the smaller surface has less freedom of movement. One by one the small 'hands' of the robot move forward. After this, the entire robot can be slide forward incrementally, whereupon the process of small surfaces shifting begins anew.
Additional experiments found that it is not only the size of the film surfaces, but also their shapes, which influence the degree of friction generated. It's remarkable that the degree of friction increases when the surface size decreases, as a result of holes being made in the structure of the film. It is therefore possible to influence the degree of friction by creating holes in the muco-adhesive or indeed by closing the holes.
The researchers are currently building a prototype that will be tested in living pigs. We must however wait a while longer until a fully developed medical device is available.
Maarten van der Sanden | alfa
Visualizing gene expression with MRI
23.12.2016 | California Institute of Technology
Illuminating cancer: Researchers invent a pH threshold sensor to improve cancer surgery
21.12.2016 | UT Southwestern Medical Center
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).
Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...
10.01.2017 | Event News
09.01.2017 | Event News
05.01.2017 | Event News
18.01.2017 | Life Sciences
18.01.2017 | Health and Medicine
17.01.2017 | Earth Sciences