Fabrication and characterization of FNPs. a,b) Schematic of FNPs for treating fibrosis. (a) FNPs function as decoys to capture various cytokines and inhibit differentiation of fibroblasts to myofibroblasts. b) FNPs are prepared into multiple formulations, including aerosol, liquid, and hydrogel to treat lung, liver, and cardiac fibrosis. c) Representative confocal images of skin fibroblasts labeled with fibroblast specific protein‐1 (FSP‐1), IL11RA, IL13RA, IL17RA, and TGFβRII. Nucleus was labeled with DAPI (4′,6‐diamidino‐2‐phenylindole). d) TEM images of bare nanoparticles (BNs) and FNPs negatively stained with uranyl acetate. e) Hydrodynamic size (diameter, nm) and zeta potential (ζ‐pot, mV). f) Size distribution curves and g) PDI of bare nanoparticles, fibroblast vesicles, and FNPs (n = 3 biologically independent samples). h) Representative confocal images showing internalization of bare nanoparticles (red) and FNPs (red) by mouse primary CFB (labeled with phalloidin, green) and Raw 264.7 cells (labeled with phalloidin, green). i) Mean fluorescence intensity (MFI) of bare nanoparticles and FNPs internalized by mouse primary CFBs (top) and Raw 264.7 cells (bottom) (n = 3 biologically independent samples). j) Western blot of TGF‐βIIR, IL11RA, IL13RA, and IL17RA in FNPs and RNPs. k) Cytokine binding capacity of FNPs and RNPs with TGF‐β1, IL11, IL13, and IL17 (n = 3 biologically independent samples). The data are expressed as mean ± s.d. (i) Data were analyzed by two‐tailed Student's t‐test, ***p < 0.001.