Scanning Electron Microscopy
We used scanning electron microscopy (SEM) to qualitatively investigate how biological matter attaches to each of the different materials. Scanning electron microscopy uses a focused beam of high-energy electrons to generate a variety of signals at the surface of solid specimens. These signals are converted into 2-dimensional high-resolution images and reveal information about the external morphology (texture), chemical composition, and crystalline structure and orientation of materials making up the sample. A subsection of each membrane material was dissected using sterile surgical scissors and mounted onto 10 mm dimeter SEM stubs with an adhesive carbon tab to prevent charge build-up. The stubs were then air dried at ambient temperature in a fume hood while partially covered to prevent dust or debris on the samples. Once completely dry, samples were coated with a thin layer of platinum (sputter coated with 3 nm of platinum using a Leica EM MED020; Leica Microsystems, Inc. Buffalo Grove, IL); a fine conducting material for high resolution electron imaging. The samples were visualized and imaged on a Zeiss 1555 VP-FESEM with SmartSEM software (Zeiss, Germany) at the Centre for Microscopy, Characterisation and Analysis (CMCA), University of Western Australia, Perth, Western Australia. We provide example SEM images of materials at 10,000 x (cellulose) and 100 x (cotton, hemp, sponge – active carbon and sponge - nitrate) magnification prior to deployment (Table 1) and provide an example of all deployed materials with biological matter attached. Due to limited supplies of chitosan and electrospun nanofiber covered cellulose membranes, none were available for SEM imagining prior to deployment.