What is the main purpose of the semipermeable membrane in dialyzers?

The main purpose of the semipermeable membrane in dialyzers is to maintain the integrity of the blood while allowing for the removal of waste products and excess water. This membrane acts as a selective barrier, enabling smaller molecules such as urea and creatinine to pass through while retaining larger molecules, such as blood cells and proteins, within the bloodstream.

During the dialysis process, the blood flows on one side of the membrane, and a dialysis solution, or dialysate, flows on the other side. The concentration gradients drive the diffusion of waste products from the blood into the dialysate, effectively cleansing the blood. Keeping blood components intact while allowing harmful substances to exit is essential for achieving a successful dialysis treatment that mimics the natural filtration of the kidneys.