From mouth to gut: microfluidic in vitro simulation of human gastro-intestinal digestion and intestinal permeability

• Published in: Analyst (London) 2023-07, Vol.148 (14), p.3193-3203
• Main Authors: Xavier, Miguel, Rodrigues, Patrícia M, Neto, Mafalda D, Guedes, Maria I, Calero, Victor, Pastrana, Lorenzo, Gonçalves, Catarina
• Format: Article
• Language: English
• Subjects: Bioavailability; Biocompatibility; Casein; Continuous flow; Digestion; Dilution; Gastrointestinal system; Microfluidics; Nanomaterials; Permeability; Simulation; Temporal resolution; Toxicity
• ISSN: 0003-2654; 1364-5528
• DOI: 10.1039/d2an02088b

Reproducible studies of bioaccessibility, intestinal absorption, and bioavailability are key to the successful development of novel food ingredients or drugs intended for oral administration. There is currently a lack of methods that offer the finesse required to study these parameters for valuable molecules typically found in small volumes - as is the case of nanomaterials, which are often used to carry and protect bioactives. Here, we describe a modular microfluidic-based platform for total simulation of the human gastro-intestinal tract. Digestion-chips and cell-based gut-chips were fabricated from PDMS by soft lithography. On-chip digestion was validated using a fluorescently labelled casein derivative, which followed typical Michaelis-Menten kinetics and showed temporal resolution and good agreement with well-established bench-top protocols. Irreversible inhibition of serine proteases using Pefabloc® SC and a 1 : 6 dilution was sufficient to mitigate the cytotoxicity of simulated digestion fluids. Caco-2/HT29-MTX co-cultures were grown on-chip under a continuous flow for 7 days to obtain a differentiated cell monolayer forming a 3D villi-like epithelium with clear tight junction formation, and with an apparent permeability ( ) of Lucifer Yellow closely approximating values reported (3.7 × 10 ± 1.4 × 10 4.0 × 10 ± 2.2 × 10 ). Digesta from the digestion-chips were flowed through the gut-chip, demonstrating the capacity to study sample digestion and intestinal permeability in a single microfluidic platform holding great promise for use in pharmacokinetic studies.