Microcantilever resonance-based DNA detection with nanoparticle probes

Microcantilevers are used to detect DNA strands with a specific sequence using gold nanoparticle modified DNA. The hybridization reactions lead to the attachment of gold nanoparticles. After the amplification process by catalyzing the nucleation of silver, the shift of the cantilever frequency signals the binding events. The method can detect target DNA at a concentration of 0.05 nM or lower. Combined with stringency washing, a single base pair mismatched DNA strand can be discriminated. The cantilever is 1/100 times smaller than its macroscopic counterpart (quartz crystal microbalance), and can be mass produced as miniaturized sensor arrays by current processing technology. Multiple DNA detection is possible by coating multiple cantilevers with various capture DNA strands and monitoring the change in their resonance frequencies. (C) 2003 American Institute of Physics.