Para este mes puedo decir que he tenido mucho progreso en las metas que me propuse en enero. He podido darle un giro final a mi investigación. Pude escribir el abstract y me encuentro en los últimos detalles. He llevado a cabo la reacción con biotina y parece tener resultados favorables. Espero que el día de la presentación sea todo un éxito. Adjunto está el abstract de mi investigación.

ABSTRACT
Waterborne and foodborne diseases are one of the principal public health problem worldwide. Our particular interest is the development of nucleic acid biosensors (NAB) for the detection of pathogenic microorganisms in food and water samples. In a NAB, a ss-nucleic acid sequence is used as a probe to identify a complementary target sequence (the analyte). The probe sequence is attached to an electrode surface and the hybridization event is then signaled using an electroactive label. Several examples of the electrochemical detection of hybridization between complementary nucleic acid oligos are available in the literature.
In this research, we report on the development of a NAB prototype using a polymer modified electrode surface together with electroactive ferrocene (Fc) derivative. To test this prototype, we are using a 158 bp PCR product of the OmpC gene from Salmonella as our probe. This PCR product has been modified to anchor it in a polystyrene-modified carbon surface as an electrode. The hybridization step is detected by looking at the Fc redox process in various schemes. For instance, we are using a cationic Fc-polymer, a Fc-Ruthenium bimetallic complex, and a water soluble Fc-PEG derivative to design different detection strategies. Our goal is to choose that configuration that affords the best response without the need for the target modification.
We have been able to synthesize several PS films and to anchor nucleic acid sequences with different lengths at gold and carbon surfaces. The hybridization event has been detected electrochemically by the conventional method, which is modifying the target with Fc-CCOH and with the Fc-PEG conjugate. We observed a small current at the potential for the Fc oxidation without signal amplification. Our experiments are now centered on testing the cationic polymer and the bimetallic complexes. We hypothesize that a Glucose Oxidase-Glucose enzyme system will augment the electrochemical signal. Once the best conditions are found, we will concentrate our efforts to build the sensor and to determine its analytical characteristics and potential for real-world applications.