Preliminary in vitro cytotoxicity screening of a bead-formed macroporous hydrophilic polymer matrix

A prescreen of the in vitro cytotoxicity of both the primary fabrication components and potential leachables from a bead-formed macroporous poly(2-hydroxyethyl methacrylate), (pHEMA) matrix has been carried out using INVITTOX Neutral red and Kenacid blue R dye binding methods. Of the eluants obtained from 24, 48, and 72-h incubated beads, only the 72-h eluant produced a greater than 20% (ID20) inhibition of 3T3-L1 cell proliferation with values of 20.98 +/- 2.33% and 21.41 +/- 1.37% inhibition for the Neutral red and Kenacid blue R binding methods, respectively. ID50 values for the fabrication components obtained using the Kenacid blue R method were generally higher than those obtained by the Neutral red assay, although the ranking of the chemicals in terms of their relative cytotoxicities was identical by both methods, i.e. ethylene glycol dimethacrylate > uranyl nitrate > purified HEMA > n-hexane > ethylene glycol (mmol 1(-1)). Whilst extended washing of finished PHEMA beads in water will reduce their acute in vitro cytotoxicity, this will only be achieved with some loss of previously encapsulated water soluble macromolecules.