RESUMO
Abstract Nowadays, a prompt and reliable diagnosis is one of the most critical measures for leprosy control. The current diagnostic is based on clinical exams by a health care professional, and it may not recognize early signs of the disease. Therefore, other leprosy diagnosis methods are needed that are sensitive, disease-specific, and easy to deliver to the end-user. This study describes the construction of an electrochemical DNA biosensor to detect PCR products of Mycobacterium leprae using methylene blue as an indicator of the hybridization. The capture probe was immobilized on the graphite electrode modified with poly(4-aminophenol). The electrode surface was morphologically characterized by atomic force microscopy. Linear voltammetry was used to monitor the concentration of methylene blue on the DNA biosensor, which indicated a limit detection of 1 x 10-10 mol/L. The biosensor showed selective when placed to hybridize with a non-complementary sequence. This study suggests that the electrochemical DNA biosensor developed is promising for detecting DNA of Mycobacterium leprae.
Assuntos
Técnicas Biossensoriais , Aminofenóis , Azul de Metileno , Mycobacterium lepraeRESUMO
In order to investigate the possibility of analysis of single strand DNA by using DNA biosensor, we developed a quartz crystal DNA biosensor and studied its performances. The single strand DNA probe was immobilized on the surface of gold filled quartz crystal by biotin immunoreaction. The DNA biosensors were used to detect the complete complementary and single base mismatch complementary single strand DNA in solution. The DNA biosensors were regenerated with 0 1mol/L HCl after hybridization. The hybridization sensitivity of quartz crystal DNA biosensor is 10ng/ml. In the range of 5～40ng/ml, there was a linear correlation between responding signals and concentrations of complementary single strand DNA with a high specificity. The DNA biosensor could be repeatedly used over 5 times by using 0 1mol/L HCl for regeneration.