Hi everyone 🙂, i'm a beginner to analog IC design. i would like to know if it is possible to simulate the circuit described in the paper 0.8V bulk-driven operational amplifier using GF180MCU-pdk or sky130pdk. thanks

Yes, you can. The inputs are biased mostly in the reverse region. If I'm not mistaken, the forward region is not recommended for sky130. Anyway, you can simulate it even if it's not recommended.