窄頻寬紅外線照射對大腸桿菌發育及蛋白質表現之影響

Abstract

本研究的目的，是設計一種紅外線發射器，利用其所發出的窄頻寬的紅外線去照射大腸桿菌24小時，找出某特定波段的紅外光對細胞發育及蛋白質表現之影響。本研究使用的紅外光發射器，是依據表面電漿子原理製作，此紅外光源結構是在矽基板上鍍上鉬金屬，再鍍上銀/二氧化矽/銀三層薄膜，而最上層的銀製作週期排列的孔洞，藉由鉬金屬通電流加熱，此結構便會發出窄頻寬高功率的紅外光；設計出發射波長為3, 3.5, 4, 4.5, 5μm，半高寬最窄可達0.5μm，加熱到300oC時發射功率可達165mW/cm2。將大腸桿菌經過不同波長之紅外光24小時的照射後，測量其細胞菌落直徑以了解生長狀態，再進而使用蛋白質二維電泳分析法分析其表現蛋白質表現，並利用質譜分析出有差異性的蛋白質。實驗結果顯示大腸桿菌在波長4, 4.5, 5μm 的照射下，會有促進生長的情形。而在紅外光24小時的照射後，其蛋白質表現都會有所不同，當紅外光有促進細胞生長時，其蛋白質有促進的調控表現。反之當細胞沒有生長差異時，其蛋白質則有抑制的調控表現。

The purpose of this study is to design an infrared emitter, and to utilize its narrow bandwidth infrared radiation to irradiate Escherichia coli for 24 hours, in order to identify the specific waveband of infrared radiation which may affect the cell development of Escherichia coli. Infrared radiation emitters used in this study are fabricated based on the principle of surface plasmon. The heat is generated by sending electric current to the molybdenum film on silicon substrate. The infrared source can be achieved by heating the triple layer structure which consists of a SiO2 layer between two Ag films on a silicon substrate. The emission wavelength can be altered by changing the lattice constant and diameter of the hole arrays. In this study, plasmonic thermal emitters with different emission peak wavelengths, i.e., 3.1, 3.5, 4.0, 4.5, and 5.0 μm, were designed and fabricated. The smallest full width at half maximum (FWHM) could be shrunk down to 0.5μm. The highest emitting power can reach 165mW/cm2 at a temperature of 300oC. After 24 hours exposure to infrared radiation with different wavelength, the cell colony diameters of Escherichia coli are measured to understand the cell growth. Two dimensional protein gel electrophoresis and mass spectrometry are also applied to observe the protein expressions pattern. From the results, the cell growth under infrared radiation with peak wavelength at 4, 4.5, 5μm is enhanced. The infrared radiation will also affect the protein expressions. When the cell growth is enhanced by the infrared radiation, its protein expressions are up-regulated. On the contrary, if the cell growth is no significant changed, its protein expressions are down-regulated.