Lysozyme-Dextran Nanogel Synthesis

Lysozyme-dextran nanogels (LDNGs) were synthesized as previously described (Li et al., 2008 (link); Coll Ferrer et al., 2014 (link); Myerson et al., 2018 (link), 2022 (link)). Rhodamine-dextran or FITC-dextran (Sigma) and lysozyme from hen egg white (Sigma) were dissolved in deionized and filtered water at a 1:1 or 2:1 mol:mol ratio. Then pH was adjusted to 7.1 and solution was lyophilized. For Maillard reaction, the lyophilized product was heated for 18 h at 60°C, with 80% humidity maintained via saturated KBr solution in the heating vessel. Dextran-lysozyme conjugates were dissolved in deionized and filtered water to a concentration of 5 mg/ml. Solutions were stirred at 80°C for 30 min. Diameter of LDNGs was evaluated with dynamic light scattering (DLS, Malvern) after heat gelation. Particle suspensions were stored at 4°C.