Multimode 5 atomic force microscope

Raman spectra of HA/PLGA/chitosan, HA/PLGA/chitosan with cell culture media, and HA/PLGA/chitosan with cells were obtained with a 100x objective using a He/Ne laser with a 60-second acquisition time, in the 100–3200 cm⁻¹ range (a Horiba Jobin Yvon Labram ARAMIS fully automated confocal Raman imaging system was used).
AFM, operating in tapping mode, was used to characterize the surface properties of the colloidal gels (Multimode V Atomic Force Microscope from Veeco Instruments, Santa Barbara, California).
The sample was made by pouring the colloidal gel inside a silicone tube. An oscillating cantilever tip at its resonance frequency was allowed to come into contact with the surface of the material and then scanned over the material; as the oscillation of the cantilever is affected by the surface topography, the feedback controller maintains the amplitude of the cantilever at a fixed set point value. The vertical movements of the cantilever tip needed to keep a constant amplitude yield the topography map; the phase map comes from the delay in oscillation of the tip that occurs in response to the excitation force [14 (link)].

Images of folded structures were obtained with a Veeco Multimode V atomic force microscope. C-type Bruker SNL-10 tips were used under tapping mode in fluid. Samples (25 μl) were deposited on the mica surface for 1 min. The mica surface was then rinsed five times with 0.5 × TE (5 mM Tris, 1 mM EDTA, adjusted to pH 8.0) supplemented with 25 mM MgCl₂. For the 2D DNA brick shapes, samples were supplemented with 5 mM NiCl₂ (final concentration) to aid in attachment to the mica surface before imaging. The 2D origami rectangle was imaged in 1 × TE (10 mM Tris, 1 mM EDTA, adjusted to pH 8.0) supplemented with 25 mM MgCl₂.

The 2D nanosheets were mechanical exfoliated from bulk single crystals and then transferred to the polished sapphire, IR quartz glass, and silicon substrates. Nanosheet height-profile measurements were performed using atomic force microscope FM-Nanoview 6800 operated in the tapping mode. Surface quality of the substrates was checked using Veeco Instruments MultiMode V atomic force microscope. Raman characterization was carried out using a confocal microscopy system (LabRAM HR Evolution) excited by 532 nm CW laser. Cross section of the VSe₂-sapphire contact was prepared using Helios 5 UX DualBeam combining a FIB and a scanning electron microscope. Before FIB cutting, the sample was coated with chromium via sputtering. High-resolution TEM images were carried out using Talos F200X instrument.