In the last years, it has been a growing interest in the development of biosensors for different applications in medicine, environmental sensing, food testing, etc.  Bridging the gap between the laboratory status of the biosensors to applications is expensive and time-consuming. Besides their design, manufacture and biofunctionalization, an extensive experimental testing work is required. One way to reduce the testing time is reusing the biosensors. With this aim, different regeneration strategies have been explored by different groups [2-4]. However, most of the protocols for regeneration require to remove the transducers from the experimental system and to reassemble the system again.
In this work, we pursue a strategy to reuse silicon-based photonic biosensors functionalized with molecular beacon (MB) probes immobilized for multiple detection of target microRNAs. This strategy aims at performing a so-called online regeneration, which not only allows saving time, but also reducing the sensor-to-sensor variance in the experimental sensing results, what is specially useful when testing similar levels of analyte. Chemical regeneration based on formamide (FA) was the strategy explored in this study. FA is a denaturing agent for nucleic acids, it is commonly used in DNA solutions . However, little is known about FA as denaturing agent for microRNA bounded to MB probes immobilized on silicon surfaces as in the case we are interested in . Our study consisted of, after running a typical microRNA sensing experiment, flowing FA in water to dehybridize the probes and regenerate the sensor for performing further experiments. Several tests were carried out and finally a regeneration protocol based on FA was successfully developed.
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