Peg nh2

PLLA (IV = 4.9 dL/g) and PDLA (IV = 3.8 dL/g) were purchased from Corbion (Gorinchem, The Netherlands). PEG with molecular weight M_n = 6000 g/mol and M_n = 15,000 g/mol were purchased from Sigma-Aldrich (St. Louis, MO, USA) and were used as received. PEG-NH2 with molecular weight M_n = 6000 g/mol and M_n = 10,000 g/mol were purchased from Sigma-Aldrich (St. Louis, MO, USA) as well.

Reduced nanographene oxide (rGOn) was produced and functionalized through a single step process, as previously described [37 (link)]. For this purpose, 10 mL of GOn (500 µg mL⁻¹) were mixed with 50 mg of poly(ethylene glycol) bis(amine) (PEG-NH₂, average M_n = 3350, Sigma, St. Louis, MO, USA). The mixture was then homogenized using an ultrasonic bath (Ovan ATM40-3LCD) for 10 min. Finally, the mixture was left in a water bath for 24 h at 90 °C. In order to remove unstable aggregates and excess PEG-NH₂, rGOn-PEG was washed four times with deionized water and centrifuged at 13,000 rpm for 10 min. After the washing step, the pellet was redispersed in water to obtain purified rGOn-PEG suspensions. As controls, GOn dispersions incubated with PEG were maintained at room temperature for 24 h; and rGOn was prepared following the same thermal reduction protocol in the absence of PEG.