BioPROTECT-Mask

PD Dr. med. Henrik Watz                              

Coordinator BioPROTECT-Mask, Recruitment of patients for mask testing on high-risk patients

Priv.-Doz. Dr. med. Frederik Trinkmann               

Sub-project manager MaskBREATHING, Recruitment of patients for mask testing on high-risk patients

Prof. Dr. Thomas Bahmer

Scientific adviser for clinical tests of MaskBREATHING

1.8.2020-31.12.2021

Protective masks represent a promising option for both self and third-party protection against SARS-CoV-2. However, it is largely unclear how the degree of separation and the pressure loss of the masks develop over the period of wear (the mask is becoming increasingly moist). For patients at risk with lung diseases, it is particularly important that the flow resistance (pressure loss) of the masks is small enough that breathing is not impeded. Therefore, in BioPROTECT-Mask, optimized masks are to be developed with the help of flow simulation, which despite a high degree of separation have a low pressure loss with good wearing comfort and thus also protect high-risk groups from SARS-CoV-2.

TP1: MaskBREATHING - Coordination: Translational Lung Research Center Heidelberg (TLRC)

Bio-aerosol protection through ready-to-use and optimized protective masks for high and low-risk patients - evaluation of lung function, physical resilience and shortness of breath in patients with chronic lung diseases

TP2: MaskCFD - Coordination: Institute for Flow in Additively Manufactured Porous Media (ISAPS), HHN

Bio-aerosol protection through ready-to-use and optimized protective masks for high and low-risk patients - optimization of protective masks with the help of flow simulation

TP3: MaskPRO - Coordination: Junker-Filter GmbH

Bio-aerosol protection through ready-to-use and optimized protective masks for high and low-risk patients - examination, design and prototype production of protective masks with optimized breathing resistance and wearing comfort

For the certified protective masks, the pressure loss and fraction separation rate, i.e. particle size-dependent separation rate, should first be measured as a function of wearing time and thus increasing humidification. All masks will be perfused both from the inside to the outside and from the outside to the inside in order to determine self-protection and protection from others. Clinical tests should determine which of these masks, thanks to the low pressure loss, are suitable for high-risk populations with chronic lung diseases and pre-existing shortness of breath, and a recommendation for suitable models or production and material characteristics will be made.

As a basis for the production of self-made everyday masks, suitable materials should first be identified on the basis of material tests, the masks should then be manufactured and, as for the certified protective masks, pressure loss and fractional separation efficiency should be measured as a function of the wearing time. Clinical studies are intended to test the effects of wearing these everyday masks on different populations of patients with chronic lung disease under controlled clinical conditions (pulmonary function tests, submaximal exercise tests, symptom scores). This will result in a production recommendation for self-made everyday masks. The results of the various work packages lead to a joint production recommendation for everyday masks that offer an optimal ratio of protection and reasonableness.

For the design of optimized protective masks, filter materials should first be tested and the 3D geometry of the filter structure determined, e.g. by μCT scans. CFD simulations on these structures and an optimization approach result in the best layering of different layers of filter materials with regard to the cost functions “minimum pressure loss” and “maximum degree of separation”. The virtually optimized protective masks are manufactured as physical prototypes and also subjected to measurements of pressure loss and fraction separation as well as clinical tests. The overall result is an optimized and validated mask prototype.

Sub-project of ISAPS, HHN

This sub-project of the BioPROTECT-Mask network focuses on the identification of certified masks that can be used by risk groups with little breath, the development of well-protective and "breathable" self-made everyday masks, the optimization of masks with the aim of reducing pressure loss (lower breathing resistance) and at the same time to increase the degree of separation (protective effect). For the latter, 3D geometries of existing filter materials are determined, e.g. based on μCT scans. In a CFD-based optimization, the layer sequence and layer thickness of the filter materials is varied with the aim of improving the degree of separation and pressure loss with regard to self-protection (flow from outside to inside) and protection against others (flow from inside to outside). The optimized virtual prototypes are built as physical prototypes in TP3. For these, pressure loss and the filtration efficiency are measured over the wearing time and thus increasing moisture penetration in order to give recommendations on how to carry them. The CFD models are validated. The virtual prototype can then serve as the basis for series development of the optimized masks.