Biology Reference
In-Depth Information
dilution was determined as optimum for the bacteria identification.
IdentificationofPCRproductshasbeenrealizedsuccessfullyin90%
of cases.
9.5 Conclusion
As it has been shown in previous sections, the use of screen-printed
electrodes as support for genosensor devices offers enormous
opportunities for their application in molecular diagnosis. The
technologies used in the fabrication of these electrodes allow the
mass production of reproducible, inexpensive and mechanically
robust strip solid electrodes. Other important advantages of these
electrodesarethepossibilityofminiaturizationaswellastheireasy
manipulation in a disposable manner and therefore the use of small
volumes, diminishing the cost of the analysis. This is an important
issue that makes this methodology for the detection of DNA more
attractive.
Moreover, in addition, the versatility of design of screen-printed
electrodes allows to carry out a simultaneous detection of several
DNA sequencesin the same analysis.
Very sensitive methods are always required for DNA sensing.
Although enough sensitivity to avoid PCR amplification has been
achievedbyuseofenzymaticlabelsormetaltags,mostoftheassays
routinelystartwithaPCRorotherbiochemicalamplification.More-
over, although label-free formats are used, most of the strategies
followedtoobtaintheanalyticalsignalinvolveseveralwashingsteps
and need the use of labeled reagents (or labeling procedures) or
indicators, whichcomplicates the assay performance.
Sensitive methodologies can also be obtained through the
electrodic modification with a nanostructured material, taking
advantage of the special characteristics that nanostructuration
offers.
References
1. F. R. R. Teles and L. P. Fonseca, Trends in DNA biosensors,
Talanta
77
(2),606-623 (2008).
