ABSTRACT
A simple electrochemical biosensor was developed for the detection of the mitochondrial NADH dehydrogenase 6 gene (MT-ND6) and its enzymatic digestion by BamHI enzyme. This biosensor was fabricated by modification of a glassy carbon electrode with gold nanoparticles (AuNPs/GCE) and a probe oligonucleotide (ssDNA/AuNPs/GCE). The probe, which is a thiolated segment of the MT-ND6 gene, was deposited by self-assembling immobilization on AuNPs/GCE. Two indicators including methylene blue (MB) and neutral red (NR) were used as the electroactive indicators and the electrochemical response of the modified electrode was measured by differential pulse voltammetry. The proposed biosensor can detect the complementary sequences of the MT-ND6 gene. Also the modified electrode was used for the detection of an enzymatic digestion process by BamHI enzyme. The electrochemical biosensor can detect the MT-ND6 gene and its enzymatic digestion in polymerase chain reaction (PCR)-amplified DNA extracted from human blood. Also the biosensor was used directly for detection of the MT-ND6 gene in all of the human genome.
Subject(s)
Electrochemistry/methods , NADH Dehydrogenase/analysis , Biosensing Techniques , Deoxyribonuclease BamHI/metabolism , Electrochemistry/instrumentation , Electrodes , Genome, Human , Gold , Humans , NADH Dehydrogenase/blood , NADH Dehydrogenase/metabolism , Nanoparticles , Nucleic Acid Hybridization , Oligonucleotides/genetics , Polymerase Chain Reaction/methodsABSTRACT
A novel carbon paste electrode modified with nanosized mesoporous MCM-41 was prepared, and used as an electrochemical sensor to study the electro oxidation of levodopa (LD), carbidopa (CD) and their mixtures. Using differential pulse voltammetry (DPV), a highly selective and simultaneous determination of LD and CD has been explored at the modified electrode. The electrochemical sensor displayed a good resolving function for the overlapping voltammetric responses of LD and CD into two separate peaks with a potential difference of 370 mV. DPV peak currents of LD increased linearly with concentration over the 0.13 µM to 1250.00 µM range and exhibited a detection limit of 0.072 µM. Also, the proposed electrochemical sensor was used for the determination of LD and CD in some real samples, using the standard addition method.
