•Model of coupled reaction–diffusion into cells encapsulated in protective polymer coating.•Dimensionless model over realistic range of physical parameters.•Impact of glucose on oxygen concentration less important than relevant oxygen parameters.•Correlated change between oxygen and glucose shown as a function of varying parameters. The coupled reaction–diffusion transport of glucose and oxygen into a core–shell geometry is modeled using dimensionless parameterization. The consumption of oxygen and glucose are coupled by a metabolic modulation function. The results are fit to a Bayesian-Ridge model that can be easily applied to generate large data sets spanning the parameter space. The non-linear correlation between the oxygen and glucose concentrations are presented and the effect of system parameters is explored. The maximum radius of a viable system is shown to decrease by up to 13.8% with high glucose saturation.