Vetex70

Root tissues (about 3 g) were ground into powder with liquid nitrogen, and the powder then immersed into 30 mL of cold ethanol. After 20 min, the solution was centrifuged at 1,000 g for 20 min, and the supernatant discarded. The pellet was washed with 20 mL of cold acetone, 20 mL of a mixture of methanol and chloroform (1:1; v/v) and 20 mL of methanol successively, and the wash was conducted at least twice with each solution. The final pellet was dried with a freeze-dried (CS110-4, Scanvac, Denmark), and the dried pellet was regarded as cell wall (Zhong and Lauchli, 1993 (link)).
The constituents of cell wall were analyzed by fourier transform infrared spectroscopy analyzer (FTIR; Vetex 70, Bruker, Germany). Spectra were recorded from 1800 to 900 cm^-1 with a resolution of 0.4 cm^-1. Before detection, every sample was normalized with background scanning. The cell wall materials were mixed with dried KBr (1: 100) and ground with agate mortar and pestle, then the mixture was weighed and pressed with a tablet machine (no more than 10 KPa). The tablet was scanned with the FTIR (Regvar et al., 2013 (link)).

The morphology of MoS₂ was measured using transmission electron microscopy (TEM; JEM-2100, JEOL). The thickness and size of the MoS₂ particles were determined with a 5500 atomic force microscope (AFM; Agilent). The zeta potential was quantified with a ZS90 Zetasizer instrument (Malvern Instruments). Dynamic light scattering (DLS) was performed with static light scattering instrument (BI-200SM, Brookhaven Instruments). UV–vis spectra were obtained on a UV3600 instrument (Shimadzu Corporation). Fourier transform infrared (FT-IR) spectroscopy was recorded on a Vetex70 (Bruker Corp., Germany). The photothermal properties of the composite were examined using a laser device (Shanghai Xilong Optoelectronics Technology Co. Ltd.) at a wavelength of 808 nm.

A Fourier transform infrared spectrophotometer (Vetex70, Bruker, Bremen, Germany) was used to measure the infrared spectroscopy of the PPI and PPI-EGCG complexes. Briefly, 1 mg powdered sample and 100 mg of KBr were mixed in an agate mortar and pressed to obtain transparent sample discs. The FTIR spectra of the samples were measured at wavelengths of 400 to 4000 cm⁻¹ and scanned 32 times at a resolution of 4 cm⁻¹.

FTIR was performed according to the method of Wang et al. [14] (link) with minor modifications. The FTIR spectra of the samples were obtained by an FTIR spectrometer (Vetex70, Bruker, Germany). The resolution was 4 cm⁻¹ and the spectral range was 4000–400 cm⁻¹. The starch sample (DW) was mixed with potassium bromide and then pressed into tablets, where the ratio of sample to potassium bromide was 1:100. The number of replicates per samples was three, background corrections were performed and normalisation of spectra was performed.

The FT-IR spectrum analysis of SBP was recorded on the Bruker-Vertex 70 Fourier transform infrared spectroscopy (FI-IR, Vetex70, Bruker Co., Ettlingen, Germany) using the KBr disk method at the scanning wavelength from 400 to 4000 cm^-1.