Electret is a kind of functional material which can store charge for a long time. The external electrical field and microcurrent produced by electret can be applied to restore the electret state of the injured tissue, to improve the microcirculation and to accelerate the union of fracture, wound and nerve regeneration. Recently, the application study of electret in life science has been proceeding briskly. This paper briefly summarizes the application situation of electret in life science.

Objective To develop a portable endoscopic thermal device which possesses the merits of compact structure,convenient operation,security and good compatibility.Methods Rapid heating elements and several materials are used,which are excellent insulation,heat conduction and can withstand high temperatures.The production process of miniaturization,anti-conglutination and constant temperatureare adopted.Results: The size of Heat probe is about 2.4mm in outer diameter and 8 mm in length.The maximum temperature will reach 250℃,heating time within 10s,output 4.5～6.5W.Conclusion Heat Probe can be compatible with various types gastrointestinal endoscopic channel.Besides hemostasis of upper gastrointestinal,it can also be applied to small polyps,erosive gastritis,etc.

Objective:To investigate the protective effect of adenosine on cochlea in acute acoustic trauma. Methods: Guinea pigs were exposed to 118 dB SPL white noise for 30 min. During the process of exposure, artificial perilymph or artificial perilymph containing adenosine (0.1 mmol/L,1 mmol/L or 5 mmol/L) was infused into the cochlea through perilymphatic perfusion. Concentration of glutamate in perilymph and thresholds of compound action potentials (CAP) were measured before and after noise exposure. Results: After exposure, the concentration of glutamate and the mean threshold shifts evoked by click were significantly higher than those of before exposure. Concentration of glutamate and thresholds of CAP in adenosine (1 mmol/L and 5 mmol/L) treated groups were significantly lower than those of the control group. Conclusion: Adenosine can inhibit the elevation of glutamate and decrease the threshold shift of CAP after exposure to noise,which can protect cochlea in acute acoustic trauma in guinea pigs.

Objective: To study the influence of electret on surface charge of fibroblast cells (3T3 cells) and to probe the relationship between cell growth, apoptosis and cell surface charge. Methods: Electrets Teflon PTFE, ±300 V,±1 000 V were used to treat 3T3 cells for 24, 48 and 72 h. Then the influences of electrets on cell cycle and surface charge of 3T3 cells were studied by flow cytometry and electrophoresis, respectively. Results: (1) After 24 h action of negative electrets, electrophoretic mobility (or surface charge) and cell number in S phase of 3T3 cells were significantly increased compared with those in control group. (2) Effect of negative electrets enhancing cell growth and increasing cell surface charge was in proportional to the surface potential of electret. (3) Surface charge density of apoptotic cell was reduced by electret. (4) After 24 h action of positive electret, the cell number in S and G2 phase were decreased and cell surface charge was also reduced. Conclusion: Negative electret can improve cell growth and increase cell surface charge density. Positive electret can restrain cell growth and reduce cell surface charge density. Surface charge of apoptotic cell is less than that of normal cell.