Heating NiTi stent in magnetic fields and the thermal effect on smooth muscle cells

The feasibility of using an alternating magnetic field from induction heating furnace to heat the NiTi stent and the influence of hyperthermic on smooth muscle cells (SMCs) have been studied in the present work. The electromagnetic field is capable of significantly heating NiTi stents and the heating temperature can be adjusted by changing the voltage and heating time of the furnace and the position of NiTi stents. The shape and living status of SMCs were influenced by the heat treatment procedures. There were three stages of SMCs reaction to heat: (1) when the temperature below 44 degrees C, the living status was not changed; (2) between 44 degrees C to 50 degrees C, the cells shrinked and were less dyed with trypan blue, which indicated that they were still alive; (3) when the temperature was above the 50 degrees C, all the cells died. It was found that from 44 degrees C to 50 degrees C, the SMCs died in apoptosis, which might allow us to heat the implanted stent to prevent restenosis.