Research into the human genome has shown that a number of genetic diseases are caused by genetic mutations. The largest degree of sequence variation in human DNA is attributed to single nucleotide polymorphisms (SNPs), which occur as often as every few hundred to few thousand base pairs in genomic DNA. Such SNPs are associated with a number of diseases and individual variations in the response to therapeutics. The identification of such basepair variations provides an opportunity in both the early diagnosis and treatment of diseases. Our laboratory is actively engaged in research into the electrochemical detection of genetic variations, DNA sequence identification and identification of species. For this purpose, we work with DNA molecules that are chemically attached to surfaces and probe the resulting film with a range of electrochemical techniques that allow the detection of single nucleotide mismatches.
There are number of factors that have been mentioned affecting the hybridization efficiency such as temperature, ionic strength, fragment length, base composition, pH and viscosity of target solution. The effects of oligonucleotide overhangs were essentially unexplored. Electrochemical impedance spectroscopy can be used to study the oligonucleotide films having overhangs on either target or the surface bound capture strand. Results indicate that comparable sizes of target and capture strands ensure the hybridization efficiency and film order.
Electrochemical Detection of Species
Towards detection of species we employ the electrochemical methodology based on the DNA array format. Different properties of surface grafted ds-DNA films resulting from the presence of base-pair mismatches provide the basis for an electrochemical method for the identification of species.