Tm 1000

Gelatin particles extracted from porcine skin were alkaline-processed, ground (Nitta Gelatin Inc., Osaka, Japan) and heated at 140 °C for 14 h under vacuum conditions. The thermally cross-linked gelatin particles were irradiated by γ-ray (25 kGy). The morphology of the prepared gelatin particles was observed by scanning electron microscopy (SEM; TM-1000, Hitachi High-Technologies Corporation, Tokyo, Japan) at an accelerating voltage of 15 kV. The particle size distribution of the gelatin particles was determined by a laser particle size analyzer (LMS-3000, Seishin Enterprise Co., Ltd., Tokyo, Japan).

All the samples were filtered using a 0.45-µm filter membrane before analysis. ${\mathrm{NO}}_3^{-}$ -N, ${\mathrm{NO}}_2^{-}$ -N and total ammonia nitrogen (TAN) concentrations were analyzed according to the Chinese SEPA standard methods (SEPA, 2002). DOC was measured using a TOC analyzer (Multi N/C 2100, Analytik Jena, Germany). The structures of the PBS/BP granules and the attached biofilm were observed using a scanning electron microscope (SEM) (TM-1000 and SU8010, Hitachi High-Technologies Corporation, Japan) on days 0, 207, and 240. A Fourier transform infrared (FTIR) spectrometer (Avatar 370, Thermo Nicolet, USA) was used to characterize the changes of the major functional groups of the PBS/BP granules before and after use.

The fiber surface condition was confirmed using SEM (TM-1000; Hitachi High-Tech Corp.) images. Cross-sectional fiber images were also obtained using SEM (S-4800; Hitachi High-Tech Corp). In addition, XRD (SmartLab; Rigaku Corp.) and EDS (QUANTAX400; Bruker Corp.) were applied for structural and elemental analyses. The copper nanoparticle sizes were found using TEM (Tecnai G2; FEI Co). After the fiber sample was ground in a mortar, it was dispersed in ethanol and dropped on the observation grid. An ATR-FTIR spectrum (Spectrum 100; PerkinElmer, Inc.) was used for structural analysis of cellulose in cotton fibers. For washing tests to compare the apparent color, washing was performed for 30 min with water at 40 °C using a commercial washing machine. Dehydration was performed for 5 min. This cycle was repeated eight times during the total 240 min washing time. After the fibers were cut off during washing, the respective appearances of materials were compared. Furthermore, the cotton fiber was immersed in a nitric acid solution after washing. The copper component of the extract solution was evaluated using ICP-optical emission spectrophotometer measurements (ICP-OES, SPS3100 SII; Hitachi High-Tech Science Corp).

Scanning electron microscopy (SEM) measurements were performed using TM-1000 (Hitachi High-Tech Co., Minato-ku, Japan), and the surfaces of the porous bodies created through crimping were observed at 1000× magnification.
X-ray CT measurements were performed using a nano3DX (Rigaku Co., Akishima, Japan) at the Industrial Technology Institute, Miyagi Prefectural Government (ITIM, Sendai, Japan). The measurement resolution was 0.629 μm, and the reconstruction range was 1.288 mm. Pore size analysis was conducted using the form/powder analysis feature of VGSTUDIO MAX 3.5.1 (Volume Graphics Co., Charlotte, NC, USA).

Gold-palladium were sputter-coated on the lyophilized fish scales, fish GelMA hydrogels and SCOSs, and the surface or cross-sectional morphologies were observed by scanning electronic microscope (SEM; Hitachi, TM-1000). To identify the morphology of myotubes loading on the DDFSs, they were fixed with paraformaldehyde and dehydrated with different concentrations of ethanol for subsequent processing. The surface elements of fish scales before and after decalcification were determined with the energy dispersive spectrometer (EDS).

Scanning electron microscopy (SEM) images were obtained on an HITACHI TM-1000 apparatus. The crystalline structures of the three different ZnO/Zn(OH)₂ macrostructure samples, namely, ZnO-S, ZnO-R, and ZnO-C were measured on a SHIMADZU XRD-6100 diffractometer with Cu Kα radiation at a wavelength of 1.5406 Å and the data were collected from 10° to 70°. The reflectance spectra covering a broad wavelength range of 200–800 nm were obtained on a SHIMADZU UV-3600 apparatus.