Efficient Enzyme-powered Micromotor-based Biosensor Fabricated By A Cyclic Alternate Hybridization Assembly

Biosensors are integrated analytical devices that combine high selective bio-recognition reactions with sensitive and convenient transducers.Developing specific,simple and low-cost biosensors has always been the goal of analytical chemists.In recent years,synthetic micro/nanomotor quickly attracted people's attention for its controllable size and shape,easy modification and batch preparation.In particularly,its self-driven feature eliminates the need for multi-step cleaning and separation due to the fluid convection induced by the rapid micromotor motion and the corresponding bubble trail,which greatly simplifies the sensing process.Through modification of various biorecepetors,motor-based biosensors have been used to detect different biomoleculars.However,traditional motor-based biosensors just use motor as a dynamic carrier while the most important character,the speed has been ignored.The separation of power layer and functional layer produced a poor sensitivity so the practical application of motor-based biosensors is still facing great challenges.In order to solve these problems,this research has been done as followsAn efficient enzyme-powered micromotor device was fabricated by assembling multiple layers of catalase on the inner surface of a poly(3,4-ethylenedioxythiophene and sodium 4-styrenesulfonate)/Au microtube(PEDOT-PSS/Au).The catalase assembly was achieved with a programmed DNA hybridization,which was performed by immobilizing a designed sandwich DNA structure as sensing unit on the PEDOT-PSS/Au,and then alternately hybridizing with two assisted DNA to binding the enzyme for efficient motor motion.The micromotor device showed unique features of good reproducibility,stability and motion performance.Under optimal conditions,it showed the speeds of 420 ?m s-1 in 2%H2O2 and even 51?s-1 in 0.25%H2O2.In the presence of target DNA,the sensing unit hybridized with target DNA to release the multi-layer DNA as well as the multi-catalase,resulting in the decrease of the motion speed.By using the speed as signal,the micromotor device could detect DNA from 10 nM to 1 ?M.The proposed micromotor device along with the cyclic alternate DNA hybridization assembly technique provided a new path to fabricate efficient and versatile micromotors,which would be an exceptional tool for rapid and simple detection of biomolecules.