A flexible microcantilever aptasensor for trace level detection of ricin

This work introduces a flexible piezoresistive microcantilever by using polyimide (PI) and silicon oxide (SiO
₂
) as the insulation layers of titanium (Ti) strain resistors. The microcantilever is elaborately devised including the strain and piezoresistive characteristics of Ti and the film formation and patterned process of the PI. The fabricated PI/Ti/SiO
₂
microcantilever is steady and flexible with less than 3 μV@3V output voltage fluctuation in PBS buffer environment and a spring constant of 21.28 nN/μm. An aptasensor is developed through functionalizing the microcantilevers, which is able to detect ricin of 10 ng/mL concentration with good specificity. All the experiment results show that the PI/Ti/SiO
₂
microcantilever-based aptasensor enables label free and high sensitivity chemical/biological molecules detection and analysis.