Contour gt k 3d optical microscope

The characterizations and imaging were performed using a Contour GT-K 3D Optical Microscope (Bruker®), a 3D non-contact surface metrology with interferometry. Samples were measured by Vertical Scan Interferometry using a 5 × Michelson magnification lens with a field of view of 1.5 × 1.5 mm, Gaussian Regression Filter, a scan speed of 1x, and thresholding of 4. Samples were placed on the profilometer device and manually adjusted to give an image on the monitor screen. The microscope used Vision 64 (Bruker®) software to control the instrument settings, data analyses, and graphical output. The measurement was performed using vertical scanning interferometry, using broadband (normally white) light source, effective for measuring objects with rough surfaces and objects with adjacent pixel-height differences greater than 135 nm. Each sample was scanned at 3 given points and averaged accordingly to determine the Ra value in micrometer (μm). This was considered as Ra1 value before immersion. Ra measurements followed the ISO 11562 recommendations for standardization [11 (link)].

Oxygen-sensing films were prepared by inserting the luminescent O₂-sensitive dye 5,10,15,20-Tetrakis-(2,3,4,5,6-pentafluorophenyl)-porphyrin-Pt(II) (PtTFPP, Por-Lab, Porphyrin-Laboratories, Scharbeutz, Germany) in a 4:1 PDMS:curing agent thin layer spin-coated on 30 mm to 35 mm rounded coverglasses. Briefly, 17 mg of PtTFPP was dissolved in 5 mL chloroform and thoroughly mixed with 2.8 mg of PDMS and 0.7 mg curing agent. The mixture was degassed in a vacuum chamber for 5 hr. About 0.5 mL to 1 mL of this solution was spread on the coverglass and spin-coated for 2 min at 500 rpm with a final speed of 2000 rpm during 10 s to flatten the edge bead. Chloroform was allowed to evaporate overnight while the polymer cured at 60°C. The final PtTFPP sensor film had a dye concentration of 4 mmol/L and was 25 μm thick. This thickness was measured using a ContourGT-K 3D Optical microscope (Bruker, Billerica, MA, USA) after removing a piece of film with a surgical blade. Sensing films were stored in dark. They were used to measure the oxygen concentration in self-generated O₂ gradients (spot assay) and for microfluidic experiments with controlled O₂ gradients.

All samples were subjected to surface profilometry using a Contour GT-K 3D Optical Microscope (Bruker, MA, USA) with associated Vision 64 software. Samples were measured by vertical scan interferometry using 5× Michelson magnification lens with a field of view of 1 mm × 1 mm, Gaussian regression filter, a scan speed of 1×, and thresholding of 4. Each sample was scanned at 3 equidistant points and averaged accordingly to determine roughness (Ra) values.

The water contact angle of each substrate was measured in triplicate by taking an image with a Dino-Lite Digital Microscope Pro (Torrance, CA USA) and then using the Low-Bond Axisymmetric Drop Shape Analysis (LBADSA) National Institutes of Health ImageJ plug-in²³ . To measure the surface roughness, the substrates were observed under a Bruker Contour GT-K 3D Optical Microscope (Billerica, MA USA). The resulting profile was then analyzed using the Bruker Vision64 Map software.

Surface roughness was evaluated using a three-dimensional high-resolution non-contact optical profiler (Contour GT-K 3D Optical Microscope, Bruker, Billerica, MA, USA). The samples were scanned at 20× magnification, at a scan speed of 1× and threshold of 5% [26 (link)]. The software Vision 64 (Bruker, Billerica, MA, USA) was used for the analysis and graphical output, and the average of three scans for every sample was taken [25 (link)]. The average surface roughness (Ra) was reported as the arithmetical mean of roughness profile [26 (link)].

Profilometer analysis was conducted with a 3D non-contact optical profilometer (Contour GT-K 3D Optical Microscope, Bruker, Billerica, MA, USA) after ultrasonic cleaning for 1 min. Ten samples were scanned for each group. Samples were scanned and measured by a vertical scan using a 5× magnification lens with a 1 mm × 1 mm field of view. Ra (roughness average), Rp (maximum peak height), and Rv (maximum valley depth) were used to quantify the surface topography of each scan.

A noncontact profilometer (Contour GT-K 3D Optical Microscope, Bruker, Billerica, MA, USA) was utilized to determine the surface roughness. The Ra value of each specimen was determined by averaging the values of 3 readings at different locations on the surface [32 (link),33 (link)].