Ethos nx5000

An area of high contrast within an osmium-stained menstrual cup was excised and securely mounted on a holder with an equal mixture of OCT compound and colloidal graphite. The mounted sample was flash-frozen in liquid nitrogen slush and transferred under vacuum into a Quorum PP3010T cryo-prep chamber. Additional sublimation was performed on the sample at −85°C for 10 min and sputter-coating with a layer of Pt for 100 s to mitigate sample charging. Scanning electron microscopy (SEM) imaging was performed using a Hitachi Ethos NX5000. The use of cryo-SEM is recognized as an invaluable tool in the visualization of biofilm that can reveal details about biofilm structure and topography that other microscopy techniques cannot (64 , 65 (link)). This tool, while limited in use due to the expense of equipment and a skill set necessary to operate the equipment and interpret the images, avoids the complication associated with complex chemistry-driven methodologies (e.g., microscopy such as FISH probes) that require oxygen to work rendering them inconducive to visualization of L. gasseri which requires anaerobic environmental conditions.

The optical absorption spectra of the dispersion sample were recorded on an ultraviolet–visible spectrophotometer (V-770, JASCO). Raman spectra in the radial-breathing mode region were recorded on an inVia Raman Microscope (Renishaw) excited by 785-nm laser light. A single-monochromator micro-Raman spectrometer was employed in the back-scattering configuration. The sample dispersions were drop-casted onto a silicon wafer before the measurement. X-ray photoelectron spectroscopy (XPS) data were obtained using an ESCALAB XI + spectrometer (Thermo Fisher Scientific) using 300 W Al–Ka radiation. To exclude the substrate signals, a highly concentrated MXene dispersion was drop-coated several times onto a Si/SiO₂ wafer to form a thick MXene film (>10 nm). Atomic force microscopy (AFM) measurements were acquired using a Dimension Fastscan AFM with a NanoScope V stage controller (Bruker). The samples for AFM observation were prepared by spin-coating the Si/SiO₂ wafer with 10 µl of the MXene dispersion at 400 rpm for 60 s, followed by 1,000 rpm for 60 s and 1,600 rpm for 60 s. Scanning electron microscopy (SEM) measurements were conducted in an S-4300 (Hitachi) or an ETHOS NX5000 (Hitachi). X-ray diffraction (XRD) spectra were obtained by a SmartLab (Rigaku) through Cu Kα radiation.