Controllable Cellular Micromotors Based on Optical Tweezers

Micromotors hold exciting prospects in biomedical applications but still face a great challenge. To date, there have been few reports of micromotors with high safety, flexible controllability, and full biocompatibility. Here, a multifunctional method based on an optical tweezer system is presented to realize controllable cellular micromotors. The method not only satisfies all of the above criteria but is also independent of the cell types and materials. Optical tweezers are used to generate a dynamic scanning optical trap along a given circular trajectory, which can trap and drive a microparticle or a single cell to move along the trajectory and thus generate a microvortex. Cells within the microvortex will be controllably rotated under an action of shear stress or torque and their rotation rate and direction can be controlled by changing the scanning frequency and direction of the dynamic optical trap. The proposed method is effective for both immotile target cells and swimming target cells. Additionally, it is further applied to realize synchronous translation and rotation of cellular micromotors and to assemble controllable and fully biocompatible cellular micromotor assays. The proposed method is believed to have potential applications in targeted drug delivery, biological microenvironment monitoring and sensing, and biomedical treatment.