ACAN	aggrecan gene
Au NPs	gold NPs
BMMSCs	bone marrow mesenchymal stem cells
CCK-8	cell counting kit 8
COL2A1	collagen type II gene
COMP	cartilage oligomeric matrix protein
DMEM	Dulbecco’s modified Eagle’s medium
ECM	extracellular matrix
ES	electrical stimulation
FBS	fetal bovine serum
FGF2	fibroblast growth factor-2
MSCs	mesenchymal stem cells
NCDCs	nasal crest-derived chondrocytes
NP	nanoparticle
OA	osteoarthritis
PBS	phosphate-buffered saline
PFA	paraformaldehyde
SD	standard deviation
TGF-β3	transforming growth factor β3
Ppy	polypyrrole
Ppy NPs	polypyrrole nanoparticles
Ppy/Au NPs	polypyrrole/gold nanocomposites