*Article* **Single Red Blood Cell Hydrodynamic Traps via the Generative Design**

**Georgii V. Grigorev 1,2, Nikolay O. Nikitin <sup>3</sup> , Alexander Hvatov <sup>3</sup> , Anna V. Kalyuzhnaya <sup>3</sup> , Alexander V. Lebedev <sup>4</sup> , Xiaohao Wang 5,\*, Xiang Qian 5,\* , Georgii V. Maksimov 6,7 and Liwei Lin <sup>2</sup>**


**Abstract:** This paper describes a generative design methodology for a micro hydrodynamic single-RBC (red blood cell) trap for applications in microfluidics-based single-cell analysis. One key challenge in single-cell microfluidic traps is to achieve desired through-slit flowrates to trap cells under implicit constraints. In this work, the cell-trapping design with validation from experimental data has been developed by the generative design methodology with an evolutionary algorithm. L-shaped trapping slits have been generated iteratively for the optimal geometries to trap living-cells suspended in flow channels. Without using the generative design, the slits have low flow velocities incapable of trapping single cells. After a search with 30,000 solutions, the optimized geometry was found to increase the through-slit velocities by 49%. Fabricated and experimentally tested prototypes have achieved 4 out of 4 trapping efficiency of RBCs. This evolutionary algorithm and trapping design can be applied to cells of various sizes.

**Keywords:** microfluidics; cell trap; RBC; evolutionary algorithm; generative design; artificial intelligence
