Pegdiol

The self-assemblies of polymer cross-linkers in a pre-gelled solution were investigated using a pyrene probe. [14 (link),15 (link)]. The pyrene (Sigma, Peabody, MA, USA) was dissolved in acetone to prepare a stock solution with a concentration of 6.0 × 10⁻⁴ M. Polymer cross-linker pre-gelled solutions were prepared in DI (deionized) water (2 mL) by poly(ethylene glycol) diacrylate of M_n 575 g/mol (PEGDA-575, Sigma) and M_w 3400 g/mol (PEGDA-3400, Sigma), respectively. In parallel, acrylate group-free poly(ethylene glycol) of M_n 3350 g/mol (PEGdiol, Sigma) were dissolved in DI water as a control. Then, the pyrene solution was dropped into the polymer solutions with varying polymer concentrations. The mixture of the polymer solution and pyrene was sonicated for 10 min to ensure dispersion of pyrene in the polymer solution. The mixture was further incubated at room temperature for at least 12 h in the dark, so the pyrene was preferentially associated with hydrophobic domains of polymers. The mixture loaded in a quartz cuvette was excited at a wavelength of 330 nm and a resulting emission spectrum was obtained using photo luminescence (QM40, Photon Technology International, HORIBA, Japan). The band-width was adjusted to 2.0 nm for both excitation and emission.

Pegloticase and 10 kDa mPEG (10 kDa p-nitrophenylcarbonate-activated monomethoxyPEG) were provided by Savient Pharmaceuticals (Bridgewater, NJ, USA). PEG-diol was obtained from Sigma-Aldrich (St. Louis, MO, USA), and PEGylated bovine adenosine deaminase (PEG-ADA) from Enzon Pharmaceuticals, Inc. (Piscataway, NJ, USA). Pegloticase was used under Investigator IND no. 11274 held by JSS.