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The discovery that synthetic short chain nucleic acids are capable of selective binding to biological targets has made them to be widely used as molecular recognition elements. These nucleic acids, called aptamers, are comprised of two types, DNA and RNA aptamers, where the DNA aptamer is preferred over the latter due to its stability, making it widely used in a number of applications. However, the success of the DNA selection process through Systematic Evolution of Ligands by Exponential Enrichment (SELEX) experiments is very much dependent on its most critical step, which is the conversion of the dsDNA to ssDNA. There is a plethora of methods available in generating ssDNA from the corresponding dsDNA. These include asymmetric PCR, biotin-streptavidin separation, lambda exonuclease digestion and size separation on denaturing-urea PAGE. Herein, different methods of ssDNA generation following the PCR amplification step in SELEX are reviewed.

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Epoxidized soybean oil (ESO) was thermally cured using methylhexahydrophthalic anhydride (MHHPA) curing agent in the presence of 2-ethyl-4-methylimidazole (EMI) catalyst. The curing characteristics of ESO/MHHPA/ EMI systems were characterized using Fourier transform infrared spectroscopy (FTIR), a dynamic mechanical analyzer (DMA) and a differential scanning calorimeter (DSC). FTIR spectra showed that the polyesterification rate in ESO/MHHPA/EMI systems increased with increasing of the catalyst concentration. DSC thermograms indicated that EMI-catalyzed ESO/MHHPA systems experienced enthalpy relaxation at low EMI concentration whereas the extent decreased with increasing of the EMI concentration. There is a direct relationship between the degree of conversion and crosslink density of the thermal cured ESO/MHHPA/EMI systems with EMI concentration. The curing characteristics of thermal curable ESO thermosetting resins were found to have influence on the thermal properties of the ESO systems. It was determined that the glass transition temperature (T g ) and storage modulus (E 0 ) of cured ESO increased with increasing the EMI concentration whereas the damping properties of the ESO/MHHPA/EMI systems exhibited the reverse trend. It was found that the thermally curable ESO thermosetting resins experienced a two-stage thermal decomposition process.