Standardized technique of water permeability measurement for biomedical applications

Standardized methods and measures are ubiquitous in biomedical engineering and a key factor for the successful development and certification of novel biomaterials, implants or other medical devices. Hence, the development of standardized measurement techniques, which can be applied to nearly every material and device is of crucial importance. Within the current work, we introduce a method to evaluate the water permeability according to ISO/FDIS 7198. The setup was designed to determine the volumetric flow through a test sample for a given hydraulic pressure. One key feature is the effortless replacement of the chamber containing the test sample. The measurement technique can thus be applied to a variety of materials and medical devices. To demonstrate the functionality of the setup we fabricated nanofiber membranes using the process of electrospinning. Nonwovens with comparable thickness and varying morphology were analyzed with regard to water permeability. In particular the different fiber diameters as well as the modified inter-fiber distances result in large deviations of the water permeability. Furthermore, there are hints for a rearrangement of the nanofibers due to the applied hydraulic pressure. The developed measurement technique provides a powerful tool for the standardized quantification of the water permeability and can be applied to a variety of biomaterials and medical devices