Axioscope 7

Particles on the filter were detected and analysed by fluorescence microscopy using the Axioscope 7 equipped with an Axiocam 503 colour camera (both Carl Zeiss AG, Germany), 565 nm LED illumination (5% intensity, 100 ms exposure), and an orange filter. Samples were observed with a 2.5 × or 5 × objective (10 µm or 5 µm resolution respectively). No colour correction was applied. A subset of samples was analysed with a 10 × objective (1 µm resolution). Due to the 10 × objective’s low depth of field, a z-stack of the sample was measured and a 2D image was generated by applying maximum projection.
Particle size, morphology, brightness, and colour were obtained with image analysis. Therefore, binary images of the scans were generated with Adobe Photoshop® (manual adjustment of brightness and contrast, separation of particles and background). Morphological attributes were obtained by analysing binary images with ImageJ. Isolated pixels (artefacts from image editing) were removed using the “open” function. Fluorescence colour and total particle brightness (TPB) were obtained with the original colour images.

Supplementary optical damage analysis was carried out via light microscope (Axioscope 7, Carl Zeiss GmbH, Graz, Austria) to support the comparability and interpretation of the performed FBPO tests. Due to the high elasticity of the elastomeric matrix material and the above-mentioned crack growth process, a camera system (Prosilica GT 6600, Allied Vision Technologies GmbH, Stadtroda, Germany) was additionally employed for all FPBO tests to improve the correlation of the recorded data of the material behavior during the pull-out with the optical-supported debonding failure process. Subsequently, the following calculation and interpretation of the results were conducted more accurately, which enabled a reliable performance prediction of the adhesive fiber–matrix bonding influenced by different interface modifications.

Hematoxylin & eosin (H&E)-stained sections of human bronchial rings and rat airway trachea were imaged using a Zeiss Axioscope 7 fluorescence microscope and a 40× oil DIC objective (NA 1.4). Cilia length data were measured manually using the freehand line tool in the image processing software Fiji ImageJ⁶⁷ . Only cilia with visible starting and end point were measured. For each rat donor, on average 15 FOVs were analyzed and on average 10 cilia were measured in each FOV. For each human donor, on average 4 FOVs were analyzed and on average 30 cilia were measured in each FOV.