Cytotoxicity-Test Artefacts in Photopolymer Evaluation: Extraction Conditions, Dose Metrics, Controls and Result Interpretation

In vitro cytotoxicity is often the first biological screen applied to a printed photopolymer, yet the measured response can be dominated by the test configuration. Extraction surface-area-to-volume ratio, specimen thickness, medium composition, serum, temperature, time, agitation, dilution, storage and evaporation determine which substances reach the cells and at what dose. Cell lineage, density, exposure duration and endpoint then shape sensitivity. Pigments, particles, photoinitiator-related species, pH or solvent carryover can also alter optical or metabolic readouts without matching cell death. This review treats cytotoxicity testing as a measurement system requiring mass-balance logic, controls and orthogonal endpoints. It distinguishes device extraction from cell-exposure dose, blank and negative controls from assay- interference controls, and a thresholded screening outcome from a mechanistic or clinical conclusion. A result becomes interpretable only when the final material state, extraction loading, extract handling, cell model, signal normalisation and uncertainty are traceable. The proposed gates prevent favourable dilution, invalid control response, optical interference or an unrepresentative coupon from being hidden inside one viability percentage. No universal extraction condition or assay is claimed for all photopolymers or devices.

ER-252 · Version 0.4.