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.

Acoustically propelled nano- and microcones: fast forward and backward motion

“…There exist two different types of acoustically propelled particles: rigid particles [26][27][28][31][32][33][34]37,38,40,41,43,44,46,51,[55][56][57][60][61][62][63][64][65] and particles with movable components. 23,40,45,50,53,54,58,59,66 The rigid particles are easier to produce in large numbers and thus of special relevance with respect to future applications, where usually a large number of particles is required. There exist also some hybrid particles that combine acoustic propulsion with other propulsion mechanisms.…”

Microfluidics for Microswimmers: Engineering Novel Swimmers and Constructing Swimming Lanes on the Microscale, a Tutorial Review

“…A series of research articles have demonstrated the ability of microswimmers to recognize, isolate, and extract different biological [8,33,77,[110][111][112] and environmental [113][114][115] targets from a complex raw medium. The surface of the microswimmers can be functionalized with various groups which helps the microswimmers to hybridize specific targets via electrostatic, magnetic, or antigen-antibody interactions.…”

“…[114] For targeted delivery, an ideal cargo carrier should release the payload once the target destination is reached. Some promising release mechanisms reported in the literature include ultrasonic, [113] chemical, [112,114] and magnetic [8] stimulation or treatment. An interesting strategy was demonstrated by Sanchez et al to capture, transport and release immotile sperm to oocytes for fertilization using magnetic microhelices.…”

“…Zhou et al tackled this problem when working with Au/Ni/Au microswimmers as bacterial transporters in microchannels. [112] The spatial confinement of the channels and oscillations of the microswimmers helped them increase the average bacteria loaded per microswimmer by about three to four times. Furthermore, by implementing this compartmentalization strategy and increased bacterial loading, the capture efficiency of the system increased by 96%.…”

Geometry Design, Principles and Assembly of Micromotors

“…Delivery of cells, drugs and proteins by NMs opened new perspectives in application of bio-nanomotors [ 275 , 276 , 277 , 278 , 279 , 280 ]. Drug delivery in vivo requires target recognition, uptake, movement and eventual release of cargo [ 281 ].…”