Efficient target capture and transport by fuel-free micromotors in a multichannel microchip

Abstract

Efficient capture and transport of biological targets by functionalized micromotors in microfluidic chips have emerged as to be promising for bioanalysis and detection of targets. However, the crucial step—target capture—is still inefficient due to the low utilization of active spots on the functionalized motor surfaces. Herein, we designed a multichannel microchip for integrating confined space with the oscillatory movement of micromotors to increase the capture efficiency. Acoustically driven, magnetically guided Au/Ni/Au micromotors were employed as the target carriers, while E. coli bacteria were chosen as the targets. Under optimized conditions, a capture efficiency of 96% and an average loading number of 3–4 (targets per single motor) could be achieved. The possibility of simple separation of targets from micromotors has also been demonstrated. This microfluidic system could facilitate the integration of multiple steps for bioanalysis and detection of targets.