S 2700

In SEM, AFM, and GIWAXD measurements, the thicknesses of active layers under all conditions were identical (15 nm). The surface morphology of Ir(III) complex films was investigated using SEM (S-2700, Hitachi, Japan). AFM images were obtained using a Veeco microscope in tapping mode over a scan area of 1 mm × 1 mm. 2D GIWAXD measurements were performed at the PLS-II 6D UNIST-PAL beamline of the Pohang Accelerator Laboratory in Korea. The X-ray coming from the bending magnet was monochromated (λ = 1.06 Å) using a double-crystal monochromator (DCM) and focused using a sagittal focusing DCM and bendable toroidal mirror system (beam size: 150 μm (H) × 120 μm (V) in FWHM @ sample position). The 2D GIWAXD measurement system was equipped with a six-axis motorized sample stage inside a vacuum chamber (~2 × 10⁻² Torr) to enable the fine alignment of a thin-film sample and effective removal of unwanted air and window scattering. The 2D GIWAXD patterns were recorded using a 2D CCD detector (Rayonix MX225-HS, USA), and the diffraction angles were calibrated using a pre-calibrated sucrose sample (monoclinic, P21, a = 10.8631 Å, b = 8.7044 Å, c = 7.7624 Å, and β = 102.938°).

Elemental analysis of the PIMs was performed using a Perkin Elmer EA2400 instrument (mineralization temperature: 925–930 °C). Thermogravimetric analysis (TGA) was done using a Mettler Toledo TGA/DSC combined instrument and a sample amount of about 10 mg. The heating cycle was from 30 °C to 650 °C at a heating rate of 10 °C/min under nitrogen atmosphere (40 mL min⁻¹). Scanning electron microscope (SEM) images (Hitachi S-2700) were taken from both surface and cross-section, obtained by cryogenic fracture, at an accelerating voltage of 15 kV. The samples were placed on a stub and coated with gold. Pore size distribution was calculated by means of FIJI software [35 (link)].

The electrospun fiber samples were mounted on aluminum stubs and then coated with gold using a Sputter Coater (Emitech). Then, the samples were examined using a Hitachi (S 2700) SEM at an accelerating voltage of 20 kV. ImageJ software (Image J, National Institutes of Health, Bethesda, MD, USA) was used to calculate average fiber diameter and diameter distribution from the SEM micrographs by randomly selecting 50 nanofibers. The results were expressed as the average diameter of the 50 nanofibers and were graphically illustrated as histograms.

The morphology of peptide/pND1 complexes was investigated by scanning electron microscopy (SEM). Freshly prepared complexes were washed three times with 300 µL of ultra-pure grade water and centrifuged (13,000× g, 12 min, 4 °C). Then, the pellet was recovered and resuspended in 40 µL of 2% tungsten solution. The samples were diluted 1:20 in ultra-pure water, 10 µL pipetted to the roundly shaped coverslip (10 mm) and left to dry overnight at room temperature. On the following day, the samples were mounted on aluminum supports, fixed with double-sided adhesive tape and sputter coated with gold using an Emitech K550 (London, UK) sputter coater. A scanning electron microscope, Hitachi S-2700 (Tokyo, Japan), with accelerating voltage of 20 kV at various magnifications, was used to determine the morphology of peptide/pND1 complexes.

The geometry and morphology of CS-TPP-pDNA NPs were evaluated by SEM. Freshly prepared systems were centrifuged (10,000 rpm, 10 min, 4 °C), the supernatant was discarded and the pellet was resuspended in phosphate-buffered saline (PBS) solution. Another centrifugation was performed in the same conditions, and the pellet was re-suspended in an aqueous solution containing 40 μL of 2 % tungsten. The samples were diluted at 1:10 in ultra-pure grade water. From the diluted solution, 10 μL was pipetted to a roundly shaped coverslip (10 mm) and left to dry overnight at room temperature. On the next day, samples were assembled on aluminum holders, attached with double-sided adhesive tape, and sputter-coated with gold using an Emitech K550 (London, UK) sputter coater. A scanning electron microscope, Hitachi S-2700 (Tokyo, Japan) with an accelerating voltage of 20 kV, was used and various magnifications were applied to evaluate the NPs morphology. TEM (Hitachi, Japan) was also performed after resuspension of nanoplexes in deionized water and sonication.

The morphology of the composite scaffolds was examined in a field emission SEM (Hitachi S-2700). The samples were frozen and broken in liquid nitrogen, mounted on aluminium platforms for horizontal/transversal view and sputter-coated with a gold–palladium conductive layer (Q3000T D Quorum sputter coater). The images were taken at an accelerating voltage of 15 kV and several magnifications.