Liquid purification or separation – Filter – Material
Patent
1996-02-01
1998-11-24
Fortuna, Ana
Liquid purification or separation
Filter
Material
21050027, 21050029, 2105003, 21050041, 21050043, 204 4, 204 49, B01D 3900
Patent
active
058401903
DESCRIPTION:
BRIEF SUMMARY
The present invention concerns biocompatible membranes and a method for the incorporation of functional groups into polymer membranes for immobilisation of bioactive molecules.
TECHNICAL FIELD
In recent years, great progress has been made in the development of medical devices for treatment of various disorders, and in the development of permanent implants to replace pans of the human body. When in use, many of these devices or implants have contact with blood for short periods of time or permanently.
Oxygenators used in heart-lung machines and hemofiltration modules used for blood purification of patients with renal insufficiencies are examples of membrane containing devices used in extracorporeal circulation of blood. These devices have large surface areas, and when used, the blood-exposure is substantial. The need for blood-compatible surface treatments for these devices is therefore obvious. Other examples of membrane containing devices are invasive blood-gas sensors and artificial organs such as artificial pancreas and artificial skin.
It is known that chemical entities having a biological activity may be bound to the surface of a substrate to improve the blood-compatibility of the substrate, if functional groups are made available on the substrate surface by surface modification. Such functional groups on the substrate surface may be charged for ionic interaction or react covalently with functional groups on the chemical entity.
PRIOR ART
When blood is exposed to artificial surfaces, several of the organism's defence systems, such as the coagulation, complement and immune systems are activated. These systems are believed to be interrelated through common intermediates. To avoid activation of the coagulation system in short time exposure of blood to foreign materials, heparin is administered systemically. It is used routinely but has several side-effects such as bleeding, thrombocytopenia or osteoporosis. Sometimes it is only partially effective, resulting in fibrin deposition on the foreign material, which leads to improper function of the device. Patients who receive blood-contacting permanent implants often have to depend on life-long anticoagulation therapies requiring frequent laboratory monitoring.
Many attempts have been made to modify surfaces of foreign materials to render them more biocompatible. A negatively charged surface is believed to give less platelet adhesion, but on the other hand enhances coagulation contact activation. The opposite has been noted for positively charged surfaces. Synthetic hemofilter membrane materials are regarded as more biocompatible, with respect to activation of the complement system, than the cellulose-based membranes. The synthetic membranes on the other hand are often hydrophobic, with high protein adsorption and sometimes inferior filtration properties. Hydrophobic surfaces are also known to promote platelet adhesion.
Biologically active surfaces, i. e. surfaces with immobilised compounds that actively participate, on a molecular level, in the process of preventing activation of the defence systems in the contact between foreign materials and body fluids or tissue, can be prepared by end-point attachment of heparin to device or implant materials surfaces, as described in Larm et al. EP-86186B1. These heparin-modified surfaces show much improved biocompatibility, both with respect to coagulation and complement activation.
Device or implant materials surfaces are generally of low reactivity, and functional groups must be introduced for coupling of bioactive reagent(s) to these surfaces. This can be achieved by coating the materials surfaces with compounds containing the proper functional groups (EP-86187B2), chemical grafting of reactive compounds (D. E. Bergbreiter in Chemically Modified Surfaces H. A. Mottola and J. R. Steinmetz (Eds) 1992 Elsevier Science publishers p.133-154.), plasma treatment with reactive monomers or gases (H. Yasuda, Plasma Polymerization, Academic Press 1985), or, in some cases, chemical reactions of the device materials to int
REFERENCES:
patent: 3441142 (1969-04-01), Oja
patent: 3522346 (1970-07-01), Chang
patent: 3616935 (1971-11-01), Love et al.
patent: 3705084 (1972-12-01), Reynolds
patent: 4102746 (1978-07-01), Goldberg
patent: 4702840 (1987-10-01), Degen
patent: 4855234 (1989-08-01), Hendricksorl et al.
patent: 4906375 (1990-03-01), Heilmann
patent: 5041225 (1991-08-01), Norman
patent: 5283186 (1994-02-01), Cunningham et al.
patent: 5420047 (1995-05-01), Brandt et al.
patent: 5476665 (1995-12-01), Dennison
Jozwiak Andrzej
Larm Olle
Scholander Elisabeth
Werynski Andrzej
Fortuna Ana
Norsk Hydro a.s.
LandOfFree
Surface modified biocompatible membranes does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Surface modified biocompatible membranes, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Surface modified biocompatible membranes will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1698540