What are the requirements for filter membrane materials used to separate plasma?

The requirements for filter membrane materials used for plasma separation will vary depending on the specific application and required results, but there are some general requirements that must be followed.

1. Biocompatibility of the filter membrane and blood. The membrane material is biocompatible to ensure that it will not cause any adverse reactions or harm to the patient's blood or plasma. For example, the membrane material or device should not cause hemolysis, that is, red blood cells. rupture or destruction, but also to minimize platelet activation and thrombosis, because excessive coagulation can lead to thrombosis or blood vessel blockage; the material itself is non-toxic, and the membrane material should not release harmful substances or infiltrate toxic compounds into the blood, because it will cause systemic Toxicity or cause adverse reactions in the body; the use of filter membranes should prohibit or minimize inflammatory reactions, and membrane materials should not trigger significant inflammatory reactions or immune reactions when in contact with blood, because excessive inflammation can cause complications and impair the normal function of the immune system Function; compatibility of the membrane with the coagulation cascade, should not interfere with the body's natural coagulation cascade responsible for blood coagulation, should not activate or inhibit coagulation factors in a manner that disrupts normal coagulation balance, etc.

2. Selectivity. The membrane should be able to selectively separate plasma from blood, thereby removing unwanted components, such as filtering red blood cells and platelets, and retaining plasma proteins. The typical diameter of human red blood cells is about 6-8 microns (μm), and platelets The average diameter of the membrane is about 2-4 micrometers (μm), and you can choose a microfiltration membrane with a pore size in the range of 0.1 to 10 micrometers (μm); in plasma protein separation, for example, the diameter of albumin is about 7 nanometers (nm), Immunoglobulins have a diameter range of 10 to 15 nm, requiring the use of smaller ultrafiltration membrane grades.

3. Membrane permeability. Membrane permeability refers to its ability to allow certain molecules or particles to pass while retaining other molecules or particles, achieving effective plasma separation while maintaining the required separation efficiency. Sufficient permeability of the filtration membrane , allowing the passage of smaller molecules, such as electrolytes, metabolites, or small solutes present in plasma, while ensuring that the main components of the plasma are not excessively removed during the separation process.

4. Mechanical strength. The membrane material should have sufficient mechanical strength to withstand the pressure difference and mechanical stress encountered during the separation process.

5. Chemical stability. The filter membrane should be chemically compatible with the components present in the plasma, including ions, proteins, enzymes and other biomolecules, and should not harm the separation process, or introduce impurities into the plasma in a manner that reacts with or reacts with these components. Interactions. Plasma separation processes often involve contact with various chemicals, detergents, or disinfectant solutions. The membrane must be able to resist chemical degradation when in full contact with these substances; the filter membrane should not leach or absorb that may contaminate the plasma or interfere with the separation. hazardous substances in the process.

6. Cost-effectiveness: Membrane materials should be cost-effective and readily available to make the plasma separation process economically feasible.

Commonly used membrane materials for plasma separation include polysulfone (PS), polyethersulfone (PES), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), etc. These types of membranes are among the requirements listed above. It has a good balance, and in actual industry applications, it also has relatively safe practical verification. Of course, the above listed are just some general directions in the selection of membrane materials. In actual applications, there are more stringent requirements. and detailed standards.