Treatments were added on day 2 after IL-1β stimulation. (A) Negative control, healthy cartilage without IL-1β stimulation. (B-E) Aggrecan-depleted plugs dosed with IL-1β and treated with (B) PBS, (C) free KAFAK, (D) empty NGPEGSS, (E) KAFAK-loaded NGPEGSS, (F) empty NGPEGMBA, and (G) KAFAK-loaded NGPEGMBA nanoparticles. Plots are normalized to individual plug weight and IL-6 production from the control and represent average ± SEM (n = 3). * denotes p < 0.05 and ** p < 0.01 with respect to the IL-1β positive control (plot B). + denotes a significant difference (p < 0.05) in IL-6 production between KAFAK-loaded NGPEGSS and NGPEGMBA nanoparticles on days 6 and 8.