Ftir spectroscopy

The FTIR of un-irradiated and irradiated sodium alginate has been performed using FTIR spectroscopy (Bruker, Unicom, Germany) at a resolution of 4 cm⁻¹ in the 4000–500 cm⁻¹ wave number range.

Human serum albumin was modified by ethylene diamine to increase its isoelectric point. In brief, HSA was dissolved in distilled water, 60 mL of 2 M ethylene diamine was added slowly to 10 mL of 20% (w/v) HSA solution, and the pH was adjusted to 4.75 with concentrated HCl, and then EDC was added to the solution. After stirring at room temperature for 4 h, the reaction was terminated by 70 mL of 4 M acetic acid buffer (pH 4.75). The obtained cationic human serum albumin was concentrated and purified at 4 °C using dialysis assay and cation exchange chromatography. The collected CHSA was concentrated at low temperature and freeze-dried for use.
The obtained CHSA was characterized by SDS-PAGE electrophoresis (Tanon, Shanghai, China), FTIR spectroscopy (Bruker, Faellanden, Switzerland), and circular dichroism (CD). The cationization degree of CHSA was determined by the trinitrobenzene sulfonic acid (TNBS) method according to previous reports [20 (link),21 (link)]. The zeta potential at different pH values of CHSA with varying degrees of cationization was determined using a dynamic light scattering instrument (Zetasizer NanoZS, Malvern, UK), and the isoelectric point of different CHSA was obtained according to the pH–zeta potential curve.

The surface modifications and the functional groups of the structures were verified using FT-IR spectroscopy (Bruker Optik GmbH, Ettlingen, Germany) in the range of 500–4000 cm⁻¹. The morphology and size of MMSNPs were evaluated by typical TEM using Carl Zeiss, LEO 906E (Germany) microscope. The surface morphology of MMSNP was investigated by field emission scanning electron microscope (FESEM) using MIRA3 FEG-SEM (Tescan, Czechia). The ξ-potential and size of MMSNPs were measured by a DLS analyzer Zetasizer, Nanotrac wave (Microtrac Inc., Montgomeryville, PA, USA). Additionally, the PDI was evaluated to illustrate the size distribution of nanoparticles. The elemental composition of materials was established by EDX using MIRA3 FEG-SEM (Tescan, Czechia).

Surface morphology of the SA/LNPs gel beads was investigated with the SEM Regulus 8220 from Hitachi, Japan. The chemical compositions of the gel beads were assessed by FT-IR spectroscopy from Bruker, ALPHA, Germany in the scanning range of 4000–500 cm⁻¹ at a resolution of 4 cm⁻¹. Thermogravimetric analysis (TGA) of the SA powder and gel beads was carried out with the Q50 thermogravimetric analyzer from TA Instruments, New Castle, DE, USA.

Scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM/EDX) was used to examine the morphology and determine the elemental composition of the metal ions bonding to Dowex 50WX8 resin under the used experimental conditions. The functional groups included in the used adsorbent were investigated using Fourier transform infrared (FT-IR) spectroscopy (Bruker) in the scanning range of 4000–400 cm⁻¹ and pH was measured using Hannah pH meter.

Functional groups of CAG-1 were analyzed by Fourier transform infrared (FT-IR) spectroscopy (Bruker, Rheinstetten, Germany). Approximately 2 mg of the sample was mixed with 200 mg of KBr and completely ground. The KBr powder was considered blank. They were placed in the pellets for scanning and recording in the range of 4,000–400 cm⁻¹.