A new gold standard approach to characterize the transport of Si across cell membranes in animals.

Silicon (Si) is increasingly recognized as an essential trace element in animals, especially since the identification of mammalian Si transport systems and Si responsive genes not long ago. During many years, however, efforts to gain substantial insight into the biological role of this element in animals have achieved partial success due in part to the unavailability of validated protocols to study Si movement across biological membranes. To circumvent such limitations, we have developed a general transport assay in which cellular Si content was determined by automated electrothermal atomic absorption spectrophotometry. We have found this assay to provide great analytic sensitivity with Si detection thresholds of less than 1 µM, that is, below or very close to the concentration range of animal cells. We have also found this assay to provide valid and cost-effective determinations in Si transport studies while requiring workable quantities of samples. The protocol described here should thus become gold standard toward accelerated progress in the field of Si transport.