how does dialysis tubing work

Dialysis tubing works as a semi-permeable membrane, typically made from materials like cellulose acetate. It allows the passage of small molecules, such as salts, waste, and small solutes, while restricting larger molecules like proteins and cells. This selective permeability facilitates the separation and removal of unwanted substances from a solution by diffusion. In practice, the tubing is filled with a solution and submerged in another fluid (a buffer or dialysate). Small molecules move through the tubing's pores from an area of higher concentration to an area of lower concentration, effectively equilibrating the solution inside the tubing with the surrounding fluid. This process can also be used to concentrate a dilute solution or to clean up biological samples by removing small unwanted molecules. The tubing is widely used in laboratories to demonstrate principles like diffusion, osmosis, and selective permeability, and it also has practical applications in medical dialysis processes to clean the blood by removing waste products and excess fluid from the body.