Biocompatible silica inorganic sculptured extracellular nanomatrices (iSECnMs) of silica nanozigzags are deposited by glancing angle deposition (GLAD), to achieve induction of specific differentiation without growth factors. The nanostructure includes a plurality of nanozigzags. The nanozigzags include SiO2 and the nanozigzags having a pitch of 80 nm to 250 nm, and a contact depth of 90 nm to 260 nm. A method of cell therapy including substantia nigra organoids formed on silica iSECnMs is also provided.