Sodium azide

The NMR heteronuclear single quantum coherence spectra were acquired using a Bruker 600 MHz magnet at the Central Alabama High Field NMR Facility at the University of Alabama at Birmingham. Samples were freshly prepared on the day of collection in 1× TBS with 2 mM BME, pH 6.8, supplemented with sodium azide (Fisher BioReagents) and deuterium oxide (99%; Cambridge Isotope Laboratories, Inc). The collected spectra were analyzed using computer-aided resonance assignment, and the peak lists were exported into Microsoft Excel for subsequent analysis. Briefly, CSPs identified using a combination of nearest neighbor and comparison to previous analysis of rBH3 binding and were quantified by calculating the ΔΔppm of each amino acid residue using the formula: √Δδ_H² + (Δδ_N/5)². Mean and standard deviation of the CSP for each residue was calculated in Microsoft Excel, and any residues demonstrating CSP >1 SD were considered significant. All spectra were collected in biological triplicate, and residues that demonstrated significant CSP in all three spectra were mapped to the ribbon model of RRM1 on PyMOL (pymol.org), using Protein Data Bank file 1SJQ: NMR structure of RRM1 from human polypyrimidine tract binding protein isoform 1 (PTB1). In Figure 4, A–C, CSPs are plotted by residue, and examples of overlaid raw data, respectively, are shown from a representative spectra.

Three different lots of skim milk was purchased from a local grocery store (Great Value, Walmart, Brookings, SD, USA). The sodium azide was obtained from Fisher Scientific (Fair Lawn, NJ, USA). The food-grade HA (Sodium hyaluronate) powder samples having three different molecular weights, 10 kDa, 200 kDa, 800 kDa, were purchased from the Stanford Chemicals Company (Lake Forest, CA, USA). The research grade HA powder with a high molecular weight of >2500 kDa was obtained from the HA works (Bedminster, NJ, USA). According to the certificate of analysis provided by suppliers, the actual MW of HA powder samples were 8 kDa, 320 kDa, 980 kDa, and 2550 kDa. The appearance of the different HA powders was white with a fine crystal texture, and the purity was >95%.

Corn oil was purchased from a local market (Albany, CA, USA). Sodium caseinate (Alanate 180) was purchased from Fonterra Co-operative Group (Auckland, New Zealand). Nystatin, 5-(N-Ethyl-N-isopropyl) amiloride (EIPA), phenylarsine oxide (PAO), Nile red, and FITC-dextran (MW 40 kDa) were purchased from Sigma-Aldrich (St. Louis, MO, USA) and used without further purification. Sodium azide was obtained from Fisher Scientific (Fair Lawn, NJ, USA). Dulbecco’s modified Eagle’s medium (DMEM) (containing 4.5 g/L D-glucose and GlutaMAX™), penicillin and streptomycin (100×), fetal bovine serum (FBS), TrypLE^TM Select, Hanks’ balanced salt solution (HBSS), and phosphate buffer solution (PBS) (10×) were purchased from GIBCO (Grand Island, NY, USA). Alexa Fluor 488 to mouse IgG and 4′,6-diamidino-2-phenylindole (DAPI) were purchased from Life Technologies (Carlsbad, CA, USA). Caco-2, a human epithelial colon adenocarcinoma cell line, was purchased from the American Type Culture Collection (Manassas, VA, USA). All other analytical grade chemicals and reagents were purchased from Fisher Scientific (Fair Lawn, NJ, USA). Ultrapure water was used in all experiments.

DMSO, acetonitrile, sodium cacodylate, sodium azide, NH₄PF₆ and NaCl were purchased from Fisher Scientific. Dichloromethane was purchased from Honeywell. Methanol, N,N-dimethylformamide, ethanol, 2,2′-dipyridylamine (dpa), calf thymus DNA, Hoechst 33258 and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) were purchased from Sigma-Aldrich. Diethylether, benzyl bromide and 1,10-phenanthroline were purchased from ACROS Organics. RuCl₃·3H₂O was purchased from Pressure Chemical. KOH and LiCl were obtained from Panreac and hydroquinone (viz. benzene-1,4-diol) from Riedel-de Haën. pBR322 plasmid was purchased from ThermoFisher Scientific. SYBR safe and 10 × TBE buffer were purchased from Invitrogen. Agarose was obtained from Ecogen. All solvents and reagents were used without further purification.

Superparamagnetic silica colloids in water with a diameter (specified by the manufacturer) of 0.51 μm ± 0.03 μm and iron oxide content ≥30% were purchased from microParticles GmbH (Berlin, Germany). Poly(ethylene oxide) (PEO, 600 kDa) was purchased from Sigma-Aldrich (St. Louis, MO, USA), sodium chloride (p.a.) from Merck (Kenilworth, NJ, USA) and sodium azide (≥99%) from Fisher Scientific (Hampton, NH, USA). All chemicals were used as received. All water used was purified by a Milli-Q water purification system.