Droplet Microfluidic-Based Low-Cost and High-Speed Microsphere Array Direct Writing Technology and Its Applications.

Microsphere arrays have significant applications and broad development prospects in various fields and disciplines. The simple, efficient, low-cost, automatic, and controllable preparation of microsphere arrays in multiple dimensions and morphologies is still a significant challenge. Here, a novel microsphere array direct writing technology was developed using a low-cost portable droplet microfluidic device and a high-precision XY movable platform. The proposed technology provided a powerful platform for the direct-writing preparation of microsphere arrays and was successfully applied to the precise and controllable fabrication of microsphere arrays with different sizes, shapes, structures, and arrangements. Additionally, gel microsphere arrays with metal ion patterns were fabricated using the microsphere arrays as templates and exhibited excellent performance in the visual analytical detection of heavy metal ions. Moreover, the simulated microsphere arrays offer a promising platform for rapidly generating high-viability and uniform 3D tumor spheroids. Therefore, given the superiority of this technology and the great potential of microsphere arrays, this simple high-speed microsphere array direct writing technology has a promising application in the multidisciplinary intersection of chemical, biological, and material sciences.