Less painful and more effective technology

Any patient who has ever had a close encounter with a catheter or endoscope knows that pain can result when body and technology meet. But new insight into the body’s mucous membranes and natural lubricants can be used to develop medical technology in order to make it less painful and more effective. And new understanding of mucus and natural lubricants may pave the way for a future in which we can replace oil-based lubricants with water-based, more environmentally friendly lubricants.



Until recently, knowledge about how mucus lubricates the body was surprisingly limited. This lack of understanding is what motivated Associate Professor Seunghwan Lee of the Department of Materials Science and Engineering to investigate, and now he is well on his way to demonstrating that mucus is more than just mucus. The lubricating function of mucus depends on the origin of species and organs.


Finding nano-level structures

Differences on the molecular level – the nano-level – are what provide the different types of mucus with their various properties. Mucus consists of specific polymers known as mucins, which have a physical structure somewhat reminiscent of a bottle brush. Mucin is composed of a central protein ’skeleton’ from which oligosaccharide chains protrude – hence the ’bottle brush’ structure. Mucins are excellent at absorbing water molecules and also constitute an effective defence against toxins and pathogens.


Seunghwan Lee has performed research on mucus originated from cows and pigs, and he has discovered that there are huge differences between the mucins found in the stomach and mouth respectively. Stomach mucins function optimally when the body's pH level is low. But in the mouth, the pH level must be close to neutral for saliva and mucus membranes to function.



Knowledge of mucins can play a central role in developing more targeted and patient-friendly medical technology. This is because tissue-contacting biomedical devices can be made far more effective if producers know exactly which microstructure the technology must work with. Sometimes it is easier to use a technology if it does not glide too easily along the tissue. At other times a very soft, smooth touch may prove more optimal.


The research angle, where natural solutions are used as inspiration for the development of modern technology – biomimetics – began to gather momentum in the 1990s. Therefore a number of improvements have already been made within the field of medical technology which build upon existing understanding of the body's own natural solutions. But the research field is a relatively new one, and there is still a great deal of room for improvements related to developing better and safer medical equipment. And this is where Seunghwan Lee hopes that his research can help to make a difference.


Contact lens must be both rough and smooth

Seunghwan Lee uses something as mundane as a contact lens to explain how important it is to control the frictional properties of medical technologies and aids. For instance, a contact lens must not be too slippery on the side that is worn next to the eye cornea otherwise it would slide around on the eyeball. Nor must there be too much friction on the outer side where the lens meets the inside of the eyelid, because then the eyelid will pull the contact lens around as it moves. Similarly, a feeding tube or endoscope used in an endoscopic exam should encounter as little resistance as possible when the tube is being guided down into the stomach. 


Body as inspiration for industry

Seunghwan Lee isn’t stopping at research into the body’s lubricants and the development of medical technology. He is also involved in research into the ways in which we can use the body’s own solutions as inspiration to develop effective industrial lubricants without using oil. The body can function with water-based lubricants, so the question is what is necessary to allow machines this possibility.


Water cannot stand up to massive pressure

One of the obstacles is that the most effective biomimetic lubrication approach to date can not handle the contact pressure found in industrial machines. Oil-in-water emulsions are used in some applications, but water cannot be used alone – yet. It is in this area that Seunghwan Lee is using the body’s solutions as inspiration to synthesise various molecules with an optimal chemical and physical structure for industrial use. And if he is successful in helping to solve this dilemma, environmentally harmful substances will be replaced with much more harmless and neutral ones in many different future contexts.


Seugwhan Lee



Seunghwan Lee’s lubricant research is divided into two projects. The first project, which investigates the composition and function of the body’s natural lubricants, is entitled: ”Soft, Slimy, Sliding Interfaces: Biotribological Properties of Mucins and Mucus gels.” The project is fully financed by the European Research Council (ERC) with a grant of DKK 10.6 million. The project will carry out a five-year research programme until the end of March 2016. The project is carried out in conjunction with the Enzyme and Protein Chemistry Department of Systems Biology, DTU.


The second project, which focuses on utilising knowledge of the body’s natural lubricants for industrial purposes, is entitled: ”A Biomimetic Approach to Lubricate Engineering Materials”. The project has a total budget of DKK 5.4 million, of which DKK 4.7 million is provided by the Danish Council for Independent Research | Technology and Production Sciences (FTP). The project will perform a three-year research programme to conclude by the end of March 2015. The project is carried out in conjunction with the Danish Polymer Centre at DTU, Department of Chemical and Biochemical Engineering DTU.




14 DECEMBER 2018