Preparation of surface-modified poly(butylene terephthalate) nonwovens and their application as leukocyte removal filters.

Blood transfusion-related adverse reactions have been reported to be caused by leukocytes in blood products. It is now generally accepted that it would be highly desirable to reduce leukocytes level as low as possible. In this study, melt-blown poly(butylene terephthalate) nonwoven (PBT-NW) was treated with a hydroxyapatite (HA) surface-modification method for removal of leukocytes from blood components. Acrylic acid was graft-polymerized onto the surface of the PBT-NW after oxygen plasma glow discharge treatment. The PBT-NW surface was covered with a thin layer of HA produced by immersing the polymer surface in an aqueous solution containing high concentrations of PO(4) (3-) and Ca(2+) after graft-polymerization of acrylic acid, which provided the nucleus for HA crystallization. The surface was characterized using water contact angles, attenuated total reflection-Fourier transform infrared (ATR-FT-IR), and electron spectroscopy for chemical analysis. When filtration was performed with a unit of red blood cell concentrates, HA-deposited PBT-NW (PBT-HA) removed 98.5% of the leukocytes and recovered 99.5% of the erythrocytes, suggesting that HA-deposited PBT-NW is a very promising blood filter for selective removal of leukocytes.