Genosensors guanine

In literature two possibilities for the detection of a DNA hybridization event in the case of carbon SPE genosensor are reported to use electroactive indicators or to detect the guanine moiety signal per se (label-free). 

Hybridization Biosensing based on the Guanine Signal (Indicator-Free Electrochemical Genosensor)... 

Lucarelli et al. describe a disposable indicator-free screen-printed genosensor applied to the detection of apoE sequences in PCR samples [26]. The biosensor format involved the immobilization of an inosine-modified (guanine-free) probe onto a SPE transducer and the detection of the duplex formation in connection with the square-wave voltammetric measurement of the guanine oxidation peak of the target sequence. 

D. Ozkan, H. Karadeniz, A. Erdem, M. Mascini, and M. Ozsoz, Electrochemical genosensor for Mitomycin C-DNA interaction based on guanine signal,/ Pharm. Biomed. Anal 35(4], 905-912 (2004]. 

The label-free DNA biosensor approach comprises the direct detection of changes of some electrical parameter from the hybridisation event. The first reported use of this kind of genosensor was by Wang et al In this work, the hybridisation event was detected by monitoring the decrease of the guanine peak of an immobilised DNA probe. 

A novel label-free electrochemical genosensor for the detection of catechol-o-methyltransferase (COMT) Val 108/158Met polymorphism based on the guanine signal change by using a disposable CGE in connection with differential pulse voltammetry... 

---