Wet grafting of nonwoven material for a leucodepletion membrane

Leukodepletion membranes are critical for enhancing the safety and quality of blood transfusions. This study investigates the wet grafting method utilized on hydrophobic nonwoven fibers for creating functionalized membranes designed for leukocyte removal. This method involves the surface modification of nonwoven via a wet grafting technique, which integrates hydrophilic or bioactive groups, thus improving the membrane's ability to capture and remove leukocytes from blood products. This thesis was performed during an internship at GVS SpA under the supervision of Dr. Marta Bonora and Msc. Najmeh Mehrabi using Fenton’s reaction, which generates hydroxyl radicals to alter the membrane's characteristics. Surface modification of a nonwoven filter requires a monomer capable of facilitating a reaction on the membrane's surface. The monomers primarily consist of hydrophilic methacrylates, which can modify the membrane's surface through the assistance of initiators and cross-linkers, transforming hydrophobic membranes into hydrophilic ones. The grafting process is optimized by varying parameters such as monomer concentration, hydroxyl radical production, and grafting duration, with the objective of improving the membrane's performance in leukocyte retention and overall filtration efficiency. The modified membranes are characterized using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), contact angle measurements, thermogravimetric analysis (TGA), static protein binding, extractables, and critical wetting surface tension (CWST), which indicate enhanced surface properties. The findings indicate that wet grafted nonwoven filters exhibit superior hydrophilic properties compared to untreated surface filters, highlighting significant progress in the advancement of surface modification technologies.