Optimization and Performance Evaluation of Melt-Blown Fiber Membranes for Leukocyte Separation from Whole Blood

Leukocytes need to be eliminated from blood components in order to lower the risk of adverse transfusion responses and guarantee patient safety during transfusion. Nowadays, nonwoven fabric filters are typically used to remove leukocytes from whole blood and blood components. Research on these types of filters, filter materials, and filtration mechanisms is increasing day by day to further enhance leukocyte removal. In this work, melt-blown nonwoven layers were produced from polybutylene terephthalate (PBT) and polyamide-12 (PA-12) and combined into eight leukocyte filter prototypes with varying architectures, such as PBT-only stacks and PBT/PA-12 multilayer combinations with ∼60-100 total layers and average pore diameters in individual layers of ∼14.7-67.8 μm. The melt-blown processing conditions (air pressure, polymer flow rate, die-collector distance, and collector speed) were screened for their influence on fiber diameter and layer thickness to produce filter-grade nonwovens. Filter morphology, pore size distribution, thermal stability, and surface charge (pHpzc) were analyzed, and filtration performance was assessed using gravity-driven whole-blood processing (450 mL per unit). Filters with both PBT and PA-12 layers removed >99% leukocytes with <10% erythrocyte loss, which is superior to PBT-only filters. This enhanced performance is ascribed to the synergistic surface properties of the mildly basic PBT and the nitrogen-containing PA-12, which facilitate adsorption-mediated leukocyte capture in the multilayer filter. In summary, these findings show that melt-blown PBT/PA-12 multilayer filters offer a scalable platform for efficient leukoreduction with low erythrocyte loss.