Nanoscope 8 multi mode

¹H NMR spectra were obtained using a Bruker AVANCElll 400 MHz spectrometer. DMSO-d₆ was used as the solvent depending on polymer solubility.
FTIR spectral studies were carried out using an IS10 670 FTIR spectrometer in the range between 4000 and 500 cm⁻¹ at a resolution of 2 cm⁻¹. All powder samples were compressed into KBr pellets in the FTIR measurements.
Atomic Force Microscope (AFM) was performed using a Bruker Nanoscope VIII Multi-Mode with a “J” scanner (scan range: 125 μm × 125 μm × 5 μm) and operated in PeakForce Tapping Mode using Bruker silicon nitride probes (Model: SCANASYST-AIR, f_o = 150 kHz, k = 0.4 N m⁻¹, length = 115 μm, width = 25 μm, tip radius: ∼2 nm) at room temperature in air conditioning. The samples were prepared by drying a drop (10 μL, 1 mg mL⁻¹) of the sample solution on a mica slice. The mica slice was finally dried overnight in a desiccator before AFM observation. All the images were “flatten” by the AFM software Nanoscope Analysis V1.40 without other processing.
The hydrodynamic sizes were determined via dynamic light scattering (DLS). Measurements were performed at 25 °C using a Nano-ZS90 equipment (Malvern Instruments Corporation, UK). The data was collected on an auto-correlator with a detection angle of scattered light at 90°. For each sample, the data from three measurements were averaged to obtain the mean ± standard deviation (SD).

Caulobacter cells grown overnight in liquid PYE were rinsed in PBS buffer and resuspended in 4% paraformaldehyde (Sigma-Aldrich) solution for 1 hr at room temperature for fixation. Cells were then rinsed in PBS buffer and filtered through polycarbonate porous membrane (Millipore, Billerica, MA, pore size: 3 µm). AFM imaging was performed using a Nanoscope VIII Multimode (Bruker Corporation, Santa Barbara, CA) and oxide-sharpened microfabricated Si₃N₄ cantilevers with a nominal spring constant of ∼0.01 N/m (Microlevers, Veeco Metrology Group). After filtering the cell culture, the filter was gently rinsed with the buffer, carefully cut (1 cm × 1 cm), attached to a steel sample puck using a small piece of double face adhesive tape, and the mounted sample was transferred into the AFM liquid cell while avoiding dewetting. Images were taken in PBS buffer in contact mode under minimal applied force. Images were analysed using Nanoscope 8.10 software (Bruker, Santa Barbara, CA). Rms (root mean square) roughness values were calculated on 250 × 250 nm² areas of the high magnification height images subjected to second order filtering.