Tetrabutylammonium bromide tbab

BOD (Myrothecium verrucaria, 2.0 U mg⁻¹, Amano Enzyme Co., Ltd., Nagoya, Japan) was used without further purification. MgOC, with an average pore size of 200 nm, was purchased from Toyo Carbon Co., Ltd., Tokyo, Japan. The GDL was donated by the Freudenberg group (H23C6, Germany). Tripotassium citrate monohydrate, sulfonic acid, hydrochloric acid, 1-methyl-2-pyrrolidone (NMP), tetrabutylammonium bromide (TBAB), and ethanol were purchased from Fujifilm Wako Pure Chemical Industries Ltd., Tsukuba, Japan. 2-Mercaptobenzoic acid (2MBA) was procured from Tokyo Chemical Industry Co., Ltd., Tokyo, Japan. Tetrachloride gold oxide (III) hydrate, Nafion^® perfluorinated resin solution (5%), and 4-mercaptobenzoic acid (4MBA) were purchased from Sigma-Aldrich, Missouri, USA. Poly(vinylidene fluoride) (PVDF, 9305, 5 wt% in NMP) was donated by Kureha Co., Ltd., Tokyo, Japan.

4(Glycidyloxymethyl)azidobenzene (AzPheEO) was prepared according to our previous report [21 (link)]. Methoxy-PEG epoxide (mPEG-EPO, Mn = 350 and 750) was purchased from Biochempeg Scientific (Boston, MA, USA). Tetrabutylammonium bromide (TBAB), ethanol, methanol, n-hexane, and N,N-dimethylformamide were purchased from FUJIFILM Wako Pure Chemical (Osaka, Japan). Ethylene oxide (EO, 1.0 mmol/L toluene solution), 4-azidobenzoic acid, lithium bromide, and triisobutyl aluminum (i-Bu₃Al, 1.0 mol/L toluene solution) were purchased from Tokyo Chemical Industry (Tokyo, Japan). Tissue culture polystyrene dishes were purchased from Iwaki (Tokyo, Japan). Alexa488-conjugated immunoglobulin G (Alexa488–IgG), fetal bovine serum (FBS), and trypsin were purchased from Thermo Fisher Scientific (Waltham, MA, USA). A penicillin–streptomycin solution was purchased from Nacalai Tesque (Kyoto, Japan).