Diagnosis of Alzheimer's disease (AD) is a complex task, and at present, neuroimaging such as magnetic resonance imaging and positron emission tomography is commonly used for the diagnosis of AD. This research work developed a new biosensing method with gold nanomaterial to identify AD biomarker of miRNA‐137. Gold nanourchin (GNU) was attached on the interdigitated electrode through the silane linker and COOH‐ended capture oligonucleotide was immobilized on the GNU surface. This surface helps to quantify the target sequence of miRNA‐137 and the detection limit reached to 0.01 pM on the linear range of 0.01–100 pM. With 3δ calculation on the linearity, the determination coefficient was noticed as y = 1.2867x − 2.2697; R2 = 0.9059. The control performances did not show a significant response, indicating the specific identification of target. [ABSTRACT FROM AUTHOR]