image: Schematic image of upward culture process of 3D multicellular spheroids on durable superamphiphobic silica aerogel surface. The antifouling surface kept cell from adhering and triggered cell self-organization into spheroids. The spheroids can be long-term incubated and in-situ observed on the surface.
Conventional methods for in-vitro biological evaluations were mostly performed on 2D monolayer cell culture. In these systems, the intensive spatial interactions between cells were totally ignored, which might lead to information loss and incorrect results. 3D cellular spheroids culture offers a possibility to mimic physiological conditions with heterogeneous spatial distribution pattern of oxygen, nutrients metabolites and signal molecules, which is an ideal model for cell research. The advent of 3D cellular spheroids is of great significance for the analysis of tumor developing mechanism, drug evaluation, stem cell differentiation and regenerative medicine.
For the generation of spheroids, the common principle is cell self-organized on a biomaterial surface that cells cannot attach and thus are forced to interact with each other. To achieve this, numerous fabrication techniques have been established previously. Among them, important examples are hanging-droplets culture, low-adhesion matrix, NASA bioreactors and magnetic manipulation. These methods open the doors for applications of spheroids. Unfortunately, such advanced methods require specialized technologies, labor-intensive handing, time-consuming procedure, and most of them are unable for in-situ observation. Therefore, it is urgent to develop a new culture method that is efficient, safe and can be able for in situ observation.
In a research article recently published in National Science Review, the research group led by Professor Qing-hua Lu proposed a novel upward culture of 3D multicellular spheroids on a durable superamphiphobic surface (SSAS). Abundant hierarchical structures and chemical inertness were constructed on the antifouling surface, leading to extremely low solid-liquid adhesion for a series of liquids with different surface tensions ranging from water to n-dodecane. The SSAS exhibited long-term thermal and mechanical stabilities. Such a robust durable SSAS meets the requirements for long-term upward culture of 3D cell spheroids. Compact 3D cell spheroids with a consistent cell population were produced with the aid of gravity and droplet curvature in the quasi-spherical droplets of the medium. Distinguished from other methods, this method is more efficient, biocompatible, reproducible and able for in situ observation. The potential applications in drug screening, spheroidal fusion and long-term tracing have been demonstrated by authors. Interestingly, this surface can be recycled without any treatment. The described SSAS offers a new technological space for in-vitro research of drug screening, stem cell differentiation, and spheroid fusion.