摘要:AbstractDue to the particular structure and functionality of the placenta, most current human placenta drug testing methods are limited to animal models, conventional cell testing, and cohort/controlled testing. Previous studies have produced inconsistent results due to physiological differences between humans and animals and limited availability of human and/or animal models for controlled testing. To overcome these challenges, a placenta‐on‐a‐chip system is developed for studying the exchange of substances to and from the placenta. Caffeine transport across the placental barrier is studied because caffeine is a xenobiotic widely consumed on a daily basis. Since a fetus does not carry the enzymes that inactivate caffeine, when it crosses a placental barrier, high caffeine intake may harm the fetus, so it is important to quantify the rate of caffeine transport across the placenta. In this study, a caffeine concentration of 0.25 mg mL−1is introduced into the maternal channel, and the resulting changes are observed over a span of 7.5 h. A steady caffeine concentration of 0.1513 mg mL−1is reached on the maternal side after 6.5 h, and a 0.0033 mg mL−1concentration on the fetal side is achieved after 5 h.During pregnancy, women may consume xenobiotic substancesthat can cross the placental barrier and cause severe damage to the fetus. Caffeine is one such xenobiotic substance ingested by pregnant women worldwide. This study is focused on using a placenta‐on‐a‐chip device to quantify the fetal caffeine concentration.