Cell Spinpods: A Simple Inexpensive Device to Determine Suspension Culture and Toxicity Effects on Renal Proximal Tubular Cells

Rotating forms of suspension culture allow cells to aggregate into spheroids, prevent the de-differentiating influence of adherence to plastic surfaces, and, perhaps most importantly of all, provide physiologically relevant, in vivo levels of shear stress. Suspension culture technology has not, however, been widely implemented, in large part because the vessels are prohibitively expensive, labor-intensive to use, and are difficult to scale for industrial applications. Our solution addresses each of these challenges in a new vessel called a cell spinpod. These small 3.5 mL capacity vessels are constructed from injection molded thermoplastic polymer components. They contain self-sealing axial silicone rubber ports, and fluoropolymer, breathable membranes. Here we report the development of injection molded cell spinpods with two-fluid modeling of the flow and stresses. Their validation was accomplished using immortalized human renal proximal tubular cells for functional assays, renal damage marker release, and differential gene expression analysis via next-generation sequencing. During exposure to myeloma immunoglobulin light chains, rotation increased both toxin-induced cell death, and release of clinically validated nephrotoxicity cytokine markers in a toxin-specific pattern. Cell spinpods are a sensitive tool for detecting nephrotoxicity in vitro.