A wireless magnetoelastic DNA-biosensor amplified by AuNPs for the detection of a common mutated DNA causing β-thalassaemia

beta-Thalassaemia is an inherited blood disorder with serious complications. Combining the unique advantages of DNA and magnetoelastic (ME) materials, an ME DNA-biosensor was proposed that can wirelessly detect a target DNA sequence (tDNA) that is a 4-bp deletion in codon 41/42 (-TTCT) in the beta-globin gene causing beta-thalassaemia. The thiolated capture probe (CP) was covalently immobilized on the surface of the gold-plated ME chip and then hybridized to tDNA, and AuNPs modified with thiolated signal probe DNA (sDNA-AuNPs) serve as the signal amplifier and the direct signal indicator, enabling label-free detection. The specific hybridization process of sDNA-AuNPs to tDNA increased the surface load mass and decreased the resonance frequency of the DNA-biosensor. The resonance frequency shift of the DNA-biosensor was linear to the logarithmic concentration of tDNA in the range of 1.0 x 10(-8) M to 1.0 x 10(-12) M, with a detection limit (LOD) of 0.571 pM (S/N = 3) and sensitivity of 72.7 Hz/nM. The ME DNA-biosensor exhibits excellent selectivity and stability for the detection of the mutated DNA (4-bp deletion in codon 41/42) causing fithalassaemia, suggesting this is a promising method for the clinical diagnosis of beta-thalassaemia.