Controllable optofluidic assembly of biological cells using an all-dielectric one-dimensional photonic crystal

Abstract

Opto-thermophoretic manipulation is emerging as an effective way for versatile trapping, guiding, and assembly of biological nanoparticles and cells. Here we report a new opto-thermophoretic tweezer based on an all-dielectric one-dimensional photonic crystal (1DPC) for reversible assembly of biological cells with a controllable center. To reveal its ability of long-range optofluidic manipulation, we demonstrate the reversible assembly of many yeast cells as well as E. coli cells that are dispersed in water solution. The 1DPC-based tweezer can also exert short-range optical gradient forces associated with focused Bloch surface waves excited on the 1DPC, which can optically trap single particles. By combining both the optical and thermophoretic manipulation, the optically trapped single polystyrene particle can work as a controllable origin of the reversible cellular assembly. Numerical simulations are performed to calculate the temperature distribution and convective flow velocity on the 1DPC, which are consistent with the experimental observations and theoretically confirm the long-range manipulations on the all-dielectric 1DPC platform. The opto-thermophoretic tweezers based on all-dielectric 1DPC endow the micromanipulation toolbox for potential applications in biomedical sciences.