Development of an electrochemical biosensor for the detection of Salmonella- Specific DNA sequences

Date

4-2010

Degree

Bachelor of Science in Chemistry

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Ernesto J. Del Rosario

Committee Member

Lou Serafin M. Lozada, Conrado P. Monterola, Jr.

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Abstract

A simple and low cost electrochemical biosensor for the detection of Salmonella- specific DNA sequences was developed in this study using pencil graphite electrodes.

Polyaniline (PANI) was deposited on the electrode surface using a two-step electrochemical deposition procedure (60 μA for 3 minutes; 30 μA for 5 minutes).

Single-stranded oligonucleotide probes were covalently immobilized on the PANI- modified electrodes through the formation of phosphoramidate bonds, completing the

development of the biosensor. DNA hybridization and the evaluation of the selectivity of the biosensor were carried out. The largest differential pulse voltammetry (DPV) peak currents were observed for the ssDNA/PANI/GE electrode, three-mismatch, and non-complementary DNA hybridized biosensor, suggesting a high selectivity of the developed biosensor. A decrease in the DPV peak current occurs upon complementary DNA hybridization due to the inaccessibility of methylene blue molecules to the guanine bases. The average DPV peak currents of methylene blue were found to be linear with the logarithm of the different concentrations of complementary DNA. The limit of detection of the electrochemical biosensor to its complementary sequence is 0.3 μM.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

LG 993.5 2010 C42 C37

Document Type

Thesis

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