A Swivel Microwell Platform for Rotational Assembly and Co-culture of Multiple Spheroids

Traditional two-dimensional (2D) cell cultures often fail to replicate the complex three-dimensional (3D) microenvironments found in vivo, where cells interact with biochemical and mechanical cues. Emerging 3D co-culture platforms better mimic intercellular interactions, cellular differentiation, and drug responses; however, existing methods-such as hydrogel encapsulation and hanging droplets-face challenges in accessibility, scalability, and ease of use. This paper presents the Swivel Microwell, a novel platform that enables efficient spheroid pairing through a simple rotational mechanism. The device, fabricated using CNC-machined poly(methyl methacrylate) (PMMA) molds and by casting polydimethylsiloxane (PDMS), utilizes gravity, surface tension, and hydrostatic pressure to facilitate spheroid assembly without the need for specialized equipment. Controlled air bubble nucleation guides precise microwell formation, allowing custom well structures on multiple surfaces. Experimental and numerical analyses confirm the platform's ability to generate multiple spheroid pairs and demonstrate its potential for high-throughput applications. The design is expected to support complex co-culture systems, including 2D-3D hybrids and multispheroid assemblies when modified. The Swivel Microwell offers an accessible, scalable, and versatile tool for dynamic spheroid manipulation, opening new possibilities for tissue engineering, drug screening, and cellular biology research.