02400nas a2200265   4500000000100000000000100001008004100002260001500043653002800058653001800086100001800104700002700122700001500149700001500164700002000179700002100199700001800220700002400238245006600262856005500328300001000383490000700393520172000400022001402120       2024                            d  c2024-05-2410aGastrointestinal models10amicrofluidics1 aVictor Calero1 aPatrícia M. Rodrigues1 aTiago Dias1 aAlar Ainla1 aAdriana Vilaça1 aLorenzo Pastrana1 aMiguel Xavier1 aCatarina Gonçalves00aA miniaturised semi-dynamic in-vitro model of human digestion  uhttps://www.nature.com/articles/s41598-024-54612-w  a119230 v143 aReliable in-vitro digestion models that are able to successfully replicate the conditions found in the human gastrointestinal tract are key to assess the fate and efficiency of new formulations aimed for oral consumption. However, current in-vitro models either lack the capability to replicate crucial dynamics of digestion or require large volumes of sample/reagents, which can be scarce when working with nanomaterials under development. Here, we propose a miniaturised digestion system, a digestion-chip, based on incubation chambers integrated on a polymethylmethacrylate device. The digestion-chip incorporates key dynamic features of human digestion, such as gradual acidification and gradual addition of enzymes and simulated fluids in the gastric phase, and controlled gastric emptying, while maintaining low complexity and using small volumes of sample and reagents. In addition, the new approach integrates real-time automated closed-loop control of two key parameters, pH and temperature, during the two main phases of digestion (gastric and intestinal) with an accuracy down to ± 0.1 °C and ± 0.2 pH points. The experimental results demonstrate that the digestion-chip successfully replicates the gold standard static digestion INFOGEST protocol and that the semi-dynamic digestion kinetics can be reliably fitted to a first kinetic order model. These devices can be easily adapted to dynamic features in an automated, sensorised, and inexpensive platform and will enable reliable, low-cost and efficient assessment of the bioaccessibility of new and expensive drugs, bioactive ingredients or nanoengineered materials aimed for oral consumption, thereby avoiding unnecessary animal testing.  a2045-2322