Affinity Changes of ssDNA Library in Vibrio SELEX by Two Detecting Methods

Affinity detection is a key step of the SELEX screening process for aptamer. Traditional detection depends on the isotope or fluorescence marker in the ssDNA library, but isotope have the danger of radiation and fluorescence is not stable enough in some situations. Therefore, searching for a new, safe and proper detection for the affinity of ssDNA library is needed for the SELEX technology. In the present paper, two colorimetry analytic methods-ELISA and OD260 methods were explored and compared to study the affinity changes in the SELEX for aptamer against Vibrio alginolyticus. The results showed that the affinity changed almost similarly in the two detecting ways. Comparatively, ELISA was a proper affinity detecting method. Although the OD260 method was seemed to be more simple and available in the SELEX, influence of some impurities on the absorbance at 260 nm could make it instable and limited its use.