A novel label-free fluorescent sensor for the detection of potassium ion based on DNAzyme

► A novel label-free potassium ions (K+) fluorescent aptasensor was developed. ► A single stranded G-rich DNA (ssDNA) was used as the recognition element for K+. ► The employed DNA specifically interacts with K+ and hemin to form a DNAzyme. ► H2O2-mediated oxidation of 3-(p-Hydroxyphenyl)-propanoic is accelerated by the DNAzyme. ► The proposed aptasensor is of high selectivity and sensitivity for K+ detection.