Types of DNA arrays

SNP arrays are a type of DNA array that can be used for genotyping, that is, for detecting SNPs within populations (54). These arrays rely on the same... 

Since rolling circle amplification takes place at a constant temperature, there is no need for the target amplification process to take place in a thermal cycler, which is required to regulate the temperature for different parts of the reaction. The type of DNA polymerase to be used in RCA is not limited to thermostable enzymes, like the PCR-based diagnostics. On the other hand, the RCA method requires the environment to be free of contaminations as the RCA arrays are highly sensitive. Wiltshire [22]... 

Different types of NA probes can be used in the fabrication of DNA arrays complementary DNA (cDNA), oligonucleotides (OND) and peptide nucleic acids (PNA). 

The choice of DNA array depends on cost, density, accuracy, and the type of DNA to be immobilized on the surface. The first criteria should be whether the chips contain immobilized cDNAs or shorter oligonucleotide sequences. The former must be spotted on the chips as complete molecules, but oligos can either be spotted or synthesized on the surface of a chip. The final criteria to select a chip should be whether the user makes or purchases the chip. Homemade systems offer limited number of spotting samples. 

This chapter has presented the technology of DNA arrays describing the different types of microarrays and the applications of each type of microarrays with some emphasis on gene expression microarray. 

A specific type of sensor array is DNA chips, mentioned in Chap. 7, Sect. 7.4. This chapter describes how a biologic species or even a specific individual can be identified by the process of hybridization, when two single strands of DNA... 

There are many protocols and different types of platforms available, e.g. GeneChips from Affymetrix, Illumina Bead Arrays, Arrays from Agilent, Applied Biosystems, GE Healthcare, customized spotted cDNA microarrays etc. the basic procedure for a large-scale measurement of gene expression involves the preparation of total or mRNA from the biological sample(s) under investigation (e.g. candidate tissue) and the hybridization of copied labelled RNA or cDNA to the DNA elements on the array surface (Fig. 1). 

Vertically aligned CNT-modified electrodes are based on a more elaborated technique than other methods, and microscopic images are used to characterize the integrity of this type of electrode. The technique has been applied for the immobilization of enzymes and DNA, and the sensors based on this technique have shown a lower detection limit than those based on other methods. More research activities using this technique, particularly with low density CNT arrays, are expected in the near future because of its sensitivity and versatility. 

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