In this paper, the semi-real time electrochemical monitoring method using a screen-printed electrode, which employs reverse transcription loop-mediated isothermal amplification (RT-LAMP) for influenza virus RNA, is presented. The amplified DNA combined with methylene blue (MB), which was used as an electroactive DNA intercalator, and the electrochemical signal was monitored using square wave voltammetry in the presence of RT-LAMP reagent components. MB molecules binding to amplified DNA caused the reduction of the peak current due to the slow diffusion of MB-amplified DNA complex to the electrode surface. We successfully monitored the amplification process of DNA on the basis of RT-LAMP by measuring and analyzing the electrochemical signal of MB with only one screen-printed electrode that connected with a USB powered portable potentiostat. The peak height of the current was related to the extent of amplification of DNA and the amount of input RNA. Since laborious probe immobilization is not required and both the amplification and the monitoring are possible in a single tube, our method does not suffer from potential cross-contamination. Furthermore, our method provides a new rote for the development of electrochemical hand held biosensors.
Influenza virus RNA was amplified by a continuous-flow polydimethylsiloxane microfluidic RT-PCR chip within 15-20 min. The amplified influenza virus RNA was observed with the naked eye, as the red color at the test line, using a lateral flow immunoassay within 1 min.
The adsorption equation for homogeneoussurface, Eq. (1), can represent single-component isotherms of hydrocarbons and carbon dioxide on activated fiber carbon KF-1 500 fairly well, but systematic deviations were observed in regions of low surface coverage. The total amount of active sites W%may be an adsorbent property which is proportional to the specific surface area. The value of W*for KF-1500 is 33% greater than that of Nuxit-AL, an activated granular carbon. The obtained parameters n and K are almost the same for the two activated carbons. The isosteric heats of adsorption calculated from the experimental isotherms decrease with increasing surface coverage for the five adsorbates on KF-1500. The curves of the isosteric heat indicate that the surface is a little heterogeneous. These observations are compatible with systematic deviations between the calculated and the experimental adsorptions. Acknowledgment Literature Cited 1) Nitta, T., T. Shigetomi, M. Kurooka and T. Katayama: /.
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