A microfluidic model for infantile in vitro digestions: Characterization of lactoferrin digestion

We present a miniaturized, flow-through model for infantile in vitro digestions, following up on our previously published in vitro digestive system for adults. Microfluidic ‘chaotic’ mixers were employed as microreactors to help emulate the biochemical processing going on in the infantile stomach and intestine. Simulated digestive fluids were introduced into these micromixers, and the mixtures were incubated for 60 min after both the gastric phase and the intestinal phase. The pH of the infantile stomach was set at 5.3, which is higher than that of adults. This leads to entirely different patterns of digestion for the milk protein, lactoferrin, used in our study as a model compound. It was found that lactoferrin remained undigested as it passed through the gastric phase and reached the intestinal phase intact, unlike in adult digestions. In the intestinal phase, lactoferrin was rapidly digested. Our miniaturized, infantile, in vitro digestive system requires much less labor and chemicals than standard approaches, and shows great potential for future automation.