A quartz crystal microbalance (QCM) system was utilized to investigate the interaction between free endotoxin lipopolysaccharide (LPS) and antibiotic polymyxin B (PmB) which was pre-immobilized on a gold (Au)-sputtered surface. PmB was immobilized by (i) chemisorbing a thiol compound with a carboxylic group (DTBA) or (ii) coating a thin layer of amino groups-rich polyethyleneimine (PEI) on the QCM probe. After a sequentially activating or cross-linking process, PmB could be immobilized on the Au surface, respectively. To assure the uniformity of modification, the DTBA-adsorbed QCM was electrochemically test. From the fact that no redox behavior of Fe (CN)64-/3- could be found, we suggested the DTBA form a high density, self-assembly monolayer on the Au surface based on a chemical adsorption, and then the negative charge of carboxylic group electrostatic repulsed Fe (CN)64- from to the Au surface. The PmB-immobilized QCM probe showed a long term stability (<10 Hz/hr) for a blank experiment even in a liquid measurement. As LPS was injected into the stirred cell in which a (i) probe was side-inserted, an adequate frequency change (△f) appeared with respect to LPS concentration and a linear relationship over the range of 1.6-6.4 μg/ml could be found. Whereas, (ii) no significant △f occurred even an arbitrary concentration of LPS was added when probe was used.
|Translated title of the contribution||酯多醣體與抗生素PmB固定化界面間之相互作用的石英壓電振盪響應探討|
|Journal||Chinese Journal of Medical and Biological Engineering|
|Publication status||Published - 1996 Dec|