Rtespa probe

An elemental analysis to quantify the nitrogen incorporated into the composites was conducted on a CHN/O Perkin Elmer 2400 Series II (Shelton, CT, USA).
Fourier transformed infrared analysis (FT-IR) of the composites, as well as of the cotton textiles, was conducted on a Nicolet iS10 (Waltham, MA, USA) with an attenuated total reflectance (ATR) accessory with a diamond tip. Each sample was scanned 64 times at a wavelength of 4000–400 nm.
Tensile testing was carried out on a MTS TestSuite™ TWElite (Eden Prairie, MN, USA) at a speed of 4.23 mm/s; composites and cotton textiles were cut into strips of 100 ± 1.5 × 15.09 ± 1.24 mm with an average thickness of 0.4 ± 0.25 mm, and samples were tested by triplicate to obtain the average value.
The composites and cotton textiles were observed using a scanning electron microscope Nova NanoSEM200 (FEI, Hillsboro, OR, USA) at low vacuum, using a low vacuum detector (LV), and a NT-MDT NTEGRA Prima AFM at room temperature, with a RTESPA probe (Bruker, Mexico City, Mexico) of spring constant k = 40 N/m in intermittent contact mode. Images of height, deflection, and phase were obtained; 100 × 100 and 20 × 20 µm² image sizes were captured systematically for each sample in the three different regions. They were analyzed with Nova 3.1 to obtain the average roughness and morphological aspect of the composites.

Energy-dispersive X-ray spectroscopy (EDX) was used to analyze the chemical composition of different sections of the samples. The samples were directly deposited on carbon tape sections fixed on aluminum supports, and no gold coating was applied in order to avoid any interferences between sulfur and gold.
The Atomic Force Microscopy (AFM) images were obtained using a Bruker Dimension Icon microscope. A thin slice of the sample was mounted onto a metallic disc glued with double-sided tape, and, for the electrical measurements, a thin layer of silver paint was used to connect the sample surface to the metallic disc and the microscope stage. Given the fact that Young’s moduli of PEDOT:PSS and PLGA are of the order of a few GPa [43 (link),44 (link)], for the nanomechanical measurements performed using the Quantitative Nanomechanics kit from Bruker, a Bruker RTESPA probe (nominal spring constant, k = 40 N/m, tip radius 8 nm) was selected since it is the one recommended for Young’s modulus ranging from 0.2 to 8.1 GPa. On the other hand, to obtain the surface potential maps by means of Kelvin Probe Force Microscopy (KPFM), a Bruker PFQNE-AL probe was used (k = 0.8 N/m, tip radius 5 nm). In this case, the work function of the tip was measured by using a gold/aluminum calibration sample (Bruker PFKPFM-SMPL) since the work function of gold can be averaged to 5.38 eV [45 ].

The exosomes isolated from the serum of BC patients were observed using an NT-MDT NTEGRA Prima AFM at room temperature, with a RTESPA probe (Bruker) of spring constant k = 40 N/m in intermittent contact mode. Images of height, deflection, and phase were obtained; images of 20 × 20, 10 × 10, and 5 × 5 μm² were captured systematically for each sample in at least three different regions. They were analyzed with WSXM software to observe the morphological aspect of exosomes [27 (link)].

The surface of the control cancer cells and the Venetin-1-treated cells was analyzed by AFM. Measurements were performed using a NanoScope V AFM microscope operated in the PeakForce Quantitative Nanomechanical Mapping mode with MultiMode 8 (Bruker, Veeco Instruments Inc.). It was equipped with NanoScope 8.15 software. The local modulus of elasticity was determined using the Derjaguin-Muller-Toporov (DMT) modulus. The nominal spring rate of the RTESPA probe (Bruker, USA) (silicone tip on a nitride lever) was 40 N/m. Young’s modulus was determined for a selected area of the A549 cell surface. The samples were prepared as described for SEM. Young’s modulus was determined for 20 fields in each sample (dark areas of low rigidity and bright areas of high rigidity). The data were analyzed statistically.

The surface of both the control and AAF-treated fungal cells was measured using NanoScope V AFM (atomic force microscope) in the Peak-Force Quantitative Nanomechanical Mapping Mode (Bruker, Vecco Instruments Inc., Billerica, MA, USA) and NanoScope 8.15 software. The nominal spring constant of the RTESPA probe (Bruker, Billerica, MA, USA) (silicone tip on the nitride lever) was 40 N/m.

Algal cells prepared as for the SEM analysis (as above) in 100% acetone were placed on a mica disc and analyzed using atomic force microscopy (AFM). The cell surface was characterized using a NanoScope V AFM (Bruker, Vecco Instruments Inc., Billerica, MA, USA) in the Peak-Force Quantitative Nanomechanical Mapping Mode and NanoScope 8.15 software. The nominal spring rate of the RTESPA probe (Bruker, Billerica, MA, USA) (silicone tip on nitride lever) was 40 N/m.

Following AFMindentation, the polished surface was partially decalcified by soaking the bones in 0.5 M EDTA for 25 minutes followed by five minutes of sonication in a water bath. This process was repeated five times for each sample. For imaging, RTESPA probes were used (Bruker; radius nominally 8 nm, spring constant  = 40 N/m). The scan size was set at 3.5 µm with 512×512 pixels and a scan rate of 0.5 lines/s. For measurements of collagen morphology, four locations were imaged per sample, and 10 to 15 fibrils were measured at each location. 40 to 50 fibrils per sample were averaged to produce a single value for each animal, though the individual tests were used for distribution comparisons. Using SPIP 5.1.10 (Image Metrology, H∅rsholm, Denmark),D-periodic spacing was calculated using2D Fast Fourier Transformations (2D FFTs) as previously described [28] (link).