Multimode 8 afm system

Topographic imaging of SLBs – DLPC and DLPC/DLPG (3:1 molar ratio) – was performed in aqueous buffers at room temperature. A Multimode 8 AFM system (Bruker AXS, CA, USA) was used to record images using Peak Force Tapping™ mode and MSNL-E cantilevers (Bruker AFM probes, USA). Images were taken at the PeakForce frequency of 2 kHz, PeakForce amplitude of 10-20 nm and PeakForce set point of 10-30 mV (<100 pN). Image processing was done using Gwyddion (http://gwyddion.net) for flattening (line-by-line background subtraction) and plane fitting. Cross-sections were recorded using Gwyddion and were then plotted using Origin (OriginLab, MA, USA). Peptides diluted in 20 mM MOPS containing 120 mM NaCl (pH 7.4) were transferred into a 100-μL fluid cell (Bruker AXS, USA) to the final concentrations stated.

Transmission electron microscopy (TEM) and high-resolution TEM (HRTEM) images of the CQDs were recorded on a Hitachi-F20 transmission electron microscope (Tokyo, Japan). The atomic force microscopy (AFM) images were recorded on a Bruker Multimode 8 AFM system (Karlsruhe, Germany). Photoluminescence (PL) measurements were conducted on a RF-6000 spectrofluorometer (Shimadzu, Japan). The X-ray photoelectron spectroscopy (XPS) analysis used an ESCALAB 250Xi (Thermo Fisher Scientific, Madison, USA) photoelectron spectrometer. Fourier transform infrared (FTIR) spectra were collected on a Bruker Nicolet 6700 spectrometer (Karlsruhe, Germany). UV-Vis absorption spectra were obtained on a 4501S UV-vis spectrophotometer (Gangdong, Tianjin, China) at room temperature. A KT7-900-434 high-speed centrifuge from Heller International Trading Co., Ltd. (Kenda, Germany) was used. The confocal microscopic images were acquired using a confocal laser scanning BX53 fluorescence–confocal microscope (Olympus, Japan). The pH value of the solution was measured by a S210 pH-meter (Mettler Toledo, Germany). All reagents were weighed with an AL104 electronic balance (Mettler Toledo Measurement Instrument Co, Ltd.; Shanghai, China).

The patterned nanocomposites were fabricated on poly(methyl methacrylate) (PMMA). Initially, PMMA thin films were produced on glass cover slips of 18 mm in diameter. The glass cover slips surfaces were first activated with oxygen plasma (Tepla 600) at 300 W for 5 min to improve the adhesion and then, a solution of PMMA (M_w 120.000, Sigma-Aldrich) on toluene (7.5 wt/v%) was spin-coated at 1000 rpm for 1 min and the resultant film annealed at 100 °C. Subsequently, the films were activated with oxygen plasma (Tepla 600) at 50 W for 1 min and the prepared (0.5 wt/v%) TiO₂ or ZnO NP dispersions spin coated. On the PMMA-NP prepared films, the moth-eye nanocomposite structures were nanoimprinted at 170 °C and 45 bars of pressure for 5 min using an Eitre 3 Nanoimprint lithography system (Obducat Technologies AB) using a PDMS working mould. As control substrates, smooth nanocomposites were prepared following the same conditions but pressed using instead a flat slab of PDMS. The PDMS working mould was obtained by replication of a master nickel mould (HT-AR-02, Temicon) as reported before.^{13 (link)} The nanocomposite substrates were imaged by scanning electron microscopy (SEM) using an Auriga FIB-SEM system (Zeiss) and by atomic force microscopy (Multimode 8 AFM system, Bruker).

AFM measurements were performed using a MultiMode 8 AFM system (Bruker). Images were taken using the Tapping Mode with V-shaped silicon nitride cantilevers with integrated pyramidal 2 nm ultrasharp tips exhibiting a spring constant and a frequency of 0.03 N m⁻¹ and 15 kHz, respectively (MSNL-D; Bruker Probes). Additional details are in Supplementary Methods.

Scanning electron microscopy (SEM) was performed on CS and CS-GG beads to characterize their topography by using a field emission scanning electron microscope JEOL (model: JSM-7600F). In addition, atomic force microscopy (AFM) was used to analyze the surface topography of CS-GG beads with a Bruker MultiMode 8 AFM system.