Label-free and high-sensitive detection of Kirsten rat sarcoma viral oncogene homolog and epidermal growth factor receptor mutation using Kelvin probe force microscopy

• Label-free and high-sensitive detection of KRAS and EGFR mutation is performed using KPFM and AuNPs.
• The detection is based on the evaluation of the surface potential of each AuNP.
• The detection method is able to detect target mutant DNA with a limit of detection of 3.3 pM, using only a single droplet.
• The detection method is able to detect selectively the KRAS mutant DNA from its wild-type DNA..

Assessment of Kirsten rat sarcoma viral oncogene homolog (KRAS) and epidermal growth factor receptor (EGFR) mutations are essential for targeted therapies of patients with non–small–cell lung cancer. In this report, we propose a label-free and high-sensitive detection method of KRAS and EGFR mutations using KPFM and a gold nanoparticle (AuNP)–based platform that densely adsorbs probe DNA and minimizes the sensing area. The detection is based on the evaluation of the surface potential of each AuNP. When AuNPs are modified with probe DNA (AuNP–pDNA), the surface potential is shifted towards the negative potential due to the negatively charged DNA backbone. When AuNP–pDNA further captures target mutant DNA through DNA hybridization, an additional surface potential shift occurs. The platform is able to detect KRAS mutant DNA (13 mer) and EGFR mutant DNA (84 mer) with a limit of detection (LOD) of 3.3 pM. Furthermore, the platform is able to detect selectively the KRAS mutant DNA from its wild-type DNA. Our proposed label-free and high-sensitive KPFM method has shown potential glimpses of a personalized medical diagnosis for cancer patients.