Nova nanosem 650

A thin 10 nm layer of gold was sputtered on the samples with a Kenosistec - UHV multitarget confocal sputter and SEM micrographs were collected with a FEI NovaNanoSEM 650.

Morphological characterization of nanofibers was performed with FEI Nova NanoSEM 650 Field Emission Scanning Electron Microscope (FE-SEM). Before the images were obtained by electron microscopy, samples were covered with gold and examined with FE-SEM at a voltage of 10 kV.
The presence of peptides in nanofibers were confirmed by comparing the retention times of peptides in nanofiber samples and peptide fractions alone by analytical RP-HPLC. For this purpose, 1 cm² sample was cut from 100 wt % of cyclotide-rich fraction/PVA nanofiber mats (NF2-100, NF3-100, NF4-100) and from the nanofiber prepared only with PVA. One-milligram/milliliter solutions were also prepared from the second, third, and fourth RP-HPLC fractions. For the analysis, a method with a flow rate of 0.3 mL/min and a gradient of 2% Solution D was used for 35 min. The retention times of peptides and PVA of the nanofibers were compared to the retention times of peptides of the three RP-HPLC fractions.

Quanta 250 SEM by FEI was used to acquire several micrographs for the surface of the 3 M Tegaderm hydrocolloid. The surface micrographs were taken under specific conditions of beam energy, chamber pressure, and magnification. It can be noticed from Table 3 that the beam energy used is relatively low to prevent charges from accumulation as the hydrocolloid is a non-conductive material. Higher energy beam however was used for observing the flake size of the silver paste.Table 3

SEM conditions for the hydrocolloid’s surface micrograph.

Figure	Beam Energy	Pressure	Magnification
Fig. 1c	2 kV	8.61 × 10−4 Pa	X 1033
Fig. 1d (left)	2 kV	6.83 × 10−4 Pa	X 58
Fig. 1d (right)	2 kV	4.55 × 10−3 Pa	X 54
Fig. 6d	10 kV	7.87 × 10-4 Pa	X4029

The cross-sectional micrograph needs more powerful SEM and thus used Nova NanoSEM 650 by FEI. This microscope provides higher magnification and enabled us to measure the thin layer of printed silver which was approximated to around 20 µm. The beam energy used in acquiring Fig. 2c is 1 kV at a magnification of x690.

The
optical performance of the PCLs was examined by measuring transmittance
using a UV–vis spectrophotometer (USB 2000+, Ocean Optics)
coupled with an optical microscope (Zeiss, 20× lens). Transmittance
readings were taken at three distinct sites within the contact lens’s
central zone to assess the nanoparticle distribution within the hydrogel
matrix.
A scanning electron microscope (FEI Nova NanoSEM 650,
resolution: 0.8 nm) was employed to scrutinize the aggregation and
distribution of nanoparticles within the PCLs. Prior to scanning electron
microscopy (SEM) imaging, the PCLs underwent a drying process at 40
°C for 6 h and were subsequently sheared using a cutter. To prevent
discharging during SEM imaging, cross sections were coated with a
10 nm thick palladium film.
The water content of the PCLs was
determined by subjecting them
to drying in an oven at 60 °C for 2 h, followed by recording
the weight. Subsequently, the samples were immersed in DI water, with
weights recorded every 2 h for 24 h until full hydration was achieved.
To evaluate the stability of the developed lenses, the samples
were exposed to the contact lens storage solution and artificial tears
for a duration of 4–2 weeks in each solution, separately. Transmittance
measurements were taken weekly to monitor any potential regression
in the optical performance attributed to nanoparticle leakage.

Scanning Electron Microscopy (SEM), FEI NovaNanoSEM 650, Hillsboro, OR, USA, is used to study surface features and energy-dispersive X-ray spectroscopy (EDX) analysis. SEM images are collected in the secondary electron imaging mode at a 5 mm working distance and an operating voltage of 5.0 or 10.0 kV, depending on the materials to be analyzed and the probing depth desired. EDX acquisition using Oxford Instruments INCA software, Oxfordshire, UK, is performed on selected regions from SEM images to confirm surface chemical composition and detect surface contaminants after completing the fabrication process.