Super-resolution imaging with randomly generated liquid-immersed polymer droplet microspheres

Microsphere-assisted microscopy has garnered significant attention and rapid development over the past decade due to its characteristics and advantages such as label-free, high resolution, low cost, real-time observation, and ease of integration. Introducing immersion liquid in microsphere-assisted super-resolution imaging not only effectively enhances imaging performance, including contrast, resolution, magnification, and clarity, but also greatly facilitates the adaptation of microsphere-assisted microscopy for applications in biological imaging scenarios. This work proposes a simple and convenient self-assembly method to generate polymer droplet microspheres immersed in liquid with random sizes and positions. The polymer droplet microspheres at random positions primarily have a size distribution in the range of approximately 3-10 μm, with the highest quantity of microspheres having a diameter of around 5 μm. Using such liquid-immersed polymer droplet microspheres as an aid to conventional white-light microscopy enables the observation of periodic grating structures with the minimum feature size of 100 nm on a Blu-ray disc. This study elucidates and explains achieving super-resolution imaging with liquid-immersed polymer droplet microspheres by integrating resolution criteria-based determination and finite element method-based numerical simulation. The research presented here holds promise as a potential candidate for assisting super-resolution imaging using liquid-immersed polymer droplet microspheres.