Selection of aptamers against cardiac troponin I by SELEX

The cardiac troponin (cTn) is a regulatory protein related with cardiac contractility variability, it consists of three subunits, cTnI, cTnT and cTnC. Detection of cardiac troponin I in serum is very specific for myocardial injury, cTnI is rapidly released into the serum when the cardiac muscle is damaged. Therefore, cTnI has become the preferred biomarkers of early diagnosis of myocardial injury. The procedure of systematic evolution of ligands by exponential enrichment (SELEX) is a method in which single-stranded oligonucleotides are selected from a wide variety of sequences, based on their interaction with a target molecule. In this work, A 81bp single stranded DNA random library was subjected to 12 rounds of selection against cardiac troponin I by SELEX. The PCR conditions for ssDNA amplification were optimized, for the purpose of establishing a more simple practical SELEX technology to screen the aptamers of cTnI for clinical diagnosis of acute myocardial infarction (AMI). The result showed that, after 12 round selection, the binding rates against cTnI increased from 1.3% at first round to 33.1% at the last round, the specific oligonucleotides were enriched to a considerable degree.