Development and technical evaluation of a reusable 3D-printed cytospin funnel for enlarged cytospin generation

Cell fixation on a microscope glass slide is a standard technique for evaluating cellular morphology in a wide range of biosamples. Cytofunnels are used in a cytocentrifuge to direct cells onto the glass slide and generate a "cytospin". Commercial cytofunnels have a fixed design with limited cytospin areas, being mostly single-use and are costly. The goal of this study was to design and manufacture a 3D-printed, customized cytofunnel that is cost-efficient, reusable and generates a larger cytospin area. We used an iterative design process using computer-aided design (CAD) software and stereolithography (SLA) printing with biocompatible resin. The funnel prototypes were subjected to a technical evaluation using two independent human pleural effusion specimens, as well as through repeated exposure to two commonly used disinfectants.

The 3D-printed cytospin funnel featured larger outlet diameters, increasing the cytospin area approximately threefold with a total manufacturing time of 24 h. The presented reusable funnel design enabled enlarged cytospin areas and increased practical cell-loading capacities under the tested conditions and may support future digital cytology and high-throughput analysis workflows. The published STL file may provide an accessible, sustainable alternative for laboratories, especially in resource-limited settings and may serve as a basis for further customization.