PRESS RELEASE
20 September, 1996
New surface coating aids use of
artificial material in body

A surface coating capable of covering material that is foreign to the body and thus hide it from the body’s immunological mechanisms may prove to be a reality. In-vitro experiments involving such a surface coating produced at Linköping University in Sweden have shown that it does not initially active the coagulation process nor the body’s complementary system. Moreover, bacteria and proteins do not readily adhere to it.

Present procedures in medical technology often employs foreign material in contact with blood and body tissues. This may give rise to problems for both the patient and the physician. Patients with surgically implanted heart valves, for instance, require life-long anticoagulant treatment. This, in turn, may lead to fatal bleeding. All foreign material represents a potential platform for bacterial growth and, moreover, increases the risk of blot clots. The complementary system may also be activated by foreign material, causing inflammation. Now, however, Swedish physicists have found a surface coating that helps avoid these problems.
“During in-vitro experiments, we have noted that the material does not initiate coagulation on contact with blood nor does protein attach to it particularly well. This means, most likely, that bacteria will adhere even less well,” says Pentti Tengvall, a physicist at the University of Linköping.
The next step will be to conduct an in-vivo experiment to be followed by the creation of products utilizing this surface. A company in Linköping, Forskarpatent AB, is now searching for interested parties capable of developing and exploiting this surface further
“At present, I chiefly envisage possibilities in areas in which foreign material has short-term contact with blood,” says Pentti Tengvall, mentioning, as an example, heart-lung machines and invasive catheters.
Nowadays, material in contact with blood is often coated with heparin, which also reduces coagulation activity. The new surface, however, has two substantial benefits as opposed to heparin: it is inexpensive, and it is easy to apply.
How the body will react to the surface coating over a long period of time is still unclear. Experiments up to the present have been conducted using blood plasma. Considerable evidence points to benefits being achieved in the long term as well, since endothelium cells are able to grow over such a surface. The surface is not toxic nor does it have any other serious side-effects.
The surface consists of two layers. An outer layer in contact with tissue is an immobilized glutation layer. This layer can be made very thin, about 10 Angstroms. The inner layer, upon which the outer layer adheres, may be either a rare metal or a polymer. This means that even pliable instruments and implants can be coated and thereby hidden from not only bacteria, but also the coagulation process and the immune system. The substratum layer of either rare metal or polymer is also very thin, only about 200 nm deep./ins

For further information, please contact:
Pentti Tengvall
Linköping University
IFM, Applied Physics
S-581 83 Linköping, Sweden
Phone +46 13 28 1370
Fax +46 13 28 8969
e-mail: pet@ifm.liv.se

or

Sten Trolle
Forskarpatent
S-581 83 Linköping
tel. +46 701 19 44 00
fax +46 13 12 22 99
e-mail: stetr@udv.liu.se