Kiwi J, Nadtochenko V
Laboratory of Photonics and Interfaces, Institute of Chemical Sciences and Engineering, Swiss Federal Institute of Technology, Lausanne 1015, Switzerland.
Langmuir. 2005 May 10;21(10):4631-41. doi: 10.1021/la046983l.
The photocatalytic peroxidation of E. coli cell, lipo-polysaccharide (LPS), phosphatidyl-ethanolcholine (PE), and peptidoglycan (PGN) of the E. coli membrane wall has been investigated on TiO2 porous films by ATR-FTIR spectroscopy. The fast reactions of the photogenerated charge carriers in TiO2 with E. coli, LPS, and PE were monitored by laser kinetic spectroscopy. ATR-FTIR spectroscopy allowed the identification of E. coli, LPS, PE, and PGN as photocatalytic peroxidation products. The PGN was observed to be the most resistant membrane wall component. Shorter peroxidation times were observed for LPS and PE. Laser photolysis shows that E. coli, LPS, and PE compete in the scavenging of a surface trapped holes (h+) with the recombination reaction of h+ with the generated electrons (e-) within times > 50 ns. This scavenging leads to the formation of organic radicals initiating the radical chain peroxidation of E. coli, LPS, PE, and PE.
通过衰减全反射傅里叶变换红外光谱（ATR-FTIR）对大肠杆菌细胞、脂多糖（LPS）、磷脂酰乙醇胺（PE）以及大肠杆菌细胞膜壁的肽聚糖（PGN）在TiO₂多孔薄膜上的光催化过氧化反应进行了研究。利用激光动力学光谱监测了TiO₂中光生载流子与大肠杆菌、LPS和PE的快速反应。ATR-FTIR光谱能够鉴定出大肠杆菌、LPS、PE和PGN为光催化过氧化产物。观察到PGN是最具抗性的膜壁成分。LPS和PE的过氧化时间较短。激光光解表明，在大于50 ns的时间内，大肠杆菌、LPS和PE在清除表面捕获的空穴（h⁺）方面与h⁺与产生的电子（e⁻）的复合反应存在竞争。这种清除导致形成有机自由基，引发大肠杆菌、LPS、PE和PE的自由基链过氧化反应。
