Paper-based biosensor for noninvasive detection of epidermal growth factor receptor mutations in non-small cell lung cancer patients

In this paper, a microfluidic paper-based electrochemical DNA biosensor was constructed for sensitive detection of EGFR mutations in patients with saliva. In order to achieve the purpose of detection, oligonucleotides were modified on the electrode surface, and the outputs of the electrochemical signal were gained by analyzing DNA hybridization reaction, after that, the horseradish peroxidase (HRP) recognized the indicator labeled on DNA and exhibited excellent electrocatalytic behavior to H2O2, bringing the rapid enhancement of current response. Under optimum conditions, the as-prepared biosensor showed a good linear relationship between the current value and logarithm of the target DNA concentration ranging from 0.5 nM to 500.0 nM and a detection limit as low as 0.167 nM. Meanwhile, the DNA biosensor emerged good stability and high specificity in distinguishing single nucleotide polymorphism of target DNA. This work not only opened a different horizon for investigating biomarker in biological fluids but also offered a promising and reliable method in biosensing and clinical diagnosis in general.