Dialysis membrane tubing

Poly(isobutylene-alt-maleic anhydride) (PIAMA, Mw: 6 kDa), poly(allylamine hydrochloride) (PAH, Mw: 58 kDa), l-histidine methyl ester dihydrochloride, 3-aminopropyltrimethoxysilane (APTMS), N,N-diisopropylethylamine (DIPEA), copper(ii) nitrate trihydrate (Cu(NO₃)₂ × 3H₂O), sodium chloride, sea salt and sodium hydroxide (all from Sigma Aldrich), N,N-dimethylformamide (DMF), dimethylsulfoxide (DMSO), toluene, methanol, acetone and isopropanol (all from Tedia) were used directly as received without further purification. Dialysis membrane tubing (MWCO: 3.5 kD) was received from Fisher Scientific. Silicon wafers (Latech Scientific Supply Pte. Ltd) were 0.6 mm thick, with one side polished and with a natural silicon dioxide layer. QSX 303 Silicon dioxide 50 nm quartz crystal microbalance (QCM) chips were obtained from Analytical Technologies Pte Ltd. Deionized (DI) water with 18 MΩ cm^–1 resistivity was obtained from a Millipore Nanopure system.

The nuclear magnetic resonance spectra were obtained with a Bruker Avance III spectrometer at 400/100 MHz resonance frequencies for proton and carbon-13 nuclei, respectively, on a room temperature BBO probe at the sample temperature of 30 °C. Samples were dissolved or diluted in deuterium oxide (D₂O, Aldrich, 99.9% atom D) containing 0.01% (v/v) acetonitrile (CH₃CN) as the internal chemical shift reference at δ_H 2.06 and δ_C 1.47 ppm (Gottlieb et al. 1997 (link)). Standard Bruker microprograms were used for acquisition of 1D (¹H, ¹³C) and 2D (COSY, HSQC, HMBC) spectra.
Laboratory reagents were obtained from commercial sources Fisher Scientific (Leicester, UK: acetonitrile, diethyl ether, isopropanol and trifluoroacetic acid) and BDH (Poole, UK: myo-inositol). In house-purified water with a Milli-Q Integral system (Merck Millipore, MA, US) was used throughout the laboratory experiments. Dialysis membrane tubing (cut-off MW 6000–8000) was purchased from Fisher Scientific.