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Although DNA recognition has been achieved using numerous biosensors with various sensing probes, the utilization of bio-interaction between DNA and biomolecules has seldom been reported in universal DNA detection. Peptides as natural molecules have the unique ability to bind to universal DNA and excellent selectivity for DNA after being functionalized with specific groups. In this work, we report a peptide based carbon nanotube (CNT) thin-film-transistor (TFT) biosensor, which can achieve sensitive sequence-independent DNA detection. In the presence of DNA, a significant increase of ΔIon could be observed within 5 minutes, which was considered to be due to the electrostatic adsorption between the DNA and peptide of opposite zeta potential. With the gradual increase of the concentration of DNA, the ΔIon signals agree with the Hill–Langmuir model (R2 = 0.98), indicating a negatively cooperative …