Orion star a111 benchtop ph meter

The schematic diagram for generating PAW from cold atmospheric pressure plasma (CAPP) is shown in Figure 1. CAPP equipment consisted of an Openair Plasmajet technology (Plasma Treat Inc., IL), where the plasma was released through a rotating nozzle (RD1004) into a discharge chamber. The plasma generator (FG5001) was operated at an air pressure of 1990 mBar, at 295 V, and a frequency of 22.5 kHz. Dry, filtered air was used as feed gas in the production of plasma.Figure 1

Schematic of PAW generation and PAW egg washing.

Figure 1Sterilized DW (300 mL) in a 1,000 mL sterile glass beaker was exposed to the plasma jet for 5 min to generate PAW. The distance between the plasma nozzle and the water surface was maintained at 7.7 cm to avoid excessive heating of the water. The final temperature of PAW was ∼50°C, and it was allowed to cool to room temperature. The pH of PAW was measured to be 2.95 ± 0.02 while the oxidation-reduction potential (ORP) was 575.8 RmV. Both the pH and the ORP values were measured using Orion Star A111 pH Benchtop Meter (Thermo Fisher Scientific, Waltham, MA) equipped with Orion 9157BNMD Triode 3-in-1 pH/ATC Probe (Thermo Fisher Scientific, Waltham, MA) and 9678BNWP Orion Metallic Combination Electrode (Redox/ORP model with Epoxy body) probe.

To eliminate the preformed peptide seeds during the purification, concentration and drying process, the peptide powder was pre-treated with HFIP (1,1,1,3,3,3-hexafluoro-2-propanol) on ice for 1 h, followed by the evaporation of HFIP in the fume hood to generate peptide film. For peptide self-assembly, the treated peptide film was dissolved in ddH₂O and the pH was adjusted with buffer of different pHs (acidic acetate buffer of pH 5.0, neutral HEPES buffer of pH 7.4 and CHES basic buffer of pH 9.5).
The nanofibril disassembly was carried out by the pH adjustment of the mature peptide nanofibrils from pH 9.5 to pH 5.0 with the addition of 1 M HCl. The mature peptide assemblies was prepared under basic pH (pH 9.5) and incubated at room temperature for two weeks. The pH adjustment was preformed by the addition of 1 M HCl and the sample pH was measured with micro pH probe (Orion™ 9810BN Micro pH Electrode. Thermo Fisher Scientific Inc.), connected to a pH meter (Orion Star™ A111 pH Benchtop Meter, Thermo Fisher Scientific Inc.).