Development of an in vitro distal gastric simulator to mimic the mechanical action of the human stomach

Abstract

This work describes the development of an in vitro distal gastric simulator (IV-DGS), where the distal region of the human stomach was replicated. Soft membranes were fabricated to simulate the gastric walls to generate a mechanical condition close to the physiological behavior. An esophageal manometry catheter was used to record the pressure amplitude values and the pressure waveform from the contractile activity. Three different experiments, considering the conditions of the fed state, were carried out to evaluate the performance of the proposed simulator. The first one was related to the evaluation of the mixing capability by dissolving methylene blue in distilled water and aqueous solutions of guar gum.The second one was focused on evaluating the acidification rate of milk with hydrochloric acid (HCl). Finally, food disintegration was evaluated using sausage and melon as meals. The IV-DGS demonstrated the capability to reproduce a pressure range between 15 and 30 mmHg, and the waveform reproduced the propulsion and retropulsion flows which were consistent with in vivo experiments reported elsewhere (Maqbool et al., 2009). The IV-DGS produced about 75 % disintegration of the pounded sausage, which represents an improvement of more than 200 % and 35 % compared to the results obtained using the static arrays without and with agitation, respectively. These experiments demonstrated how important the mechanical dynamic conditions are to promote the chemical and mechanical reaction during in vitro digestion simulations.

Keywords: Gastric emptying; Gastric in vitro model; Gastric pressure forces; Gastric simulator; Soft actuator.