Development of a Robotic Capsule for in vivo Sampling of Gut Microbiota

Abstract

Human gut microbiota can provide comprehensive information about the health of a host but the tools to collect microbiome samples are not currently available. A standalone wireless robotic capsule that has been developed in this study, collects the microbiota both from lumen (capsule surrounding) and intestinal wall (mucosa layer) for the first time. First, a two-way shape memory alloy (SMA) spring actuation system was developed by tackling the high-drain current requirement of SMAs. The actuator can produce a 800 mN force that was sufficient to collect samples. Second, successful encapsulation of the collected sample to avoid contamination was realised by testing 3 main sealing materials. Third, the robotic capsule was tested in a gut simulator that mimics in-vivo environment to ensure successful and safe travel of the capsule along the gastrointestinal tract. Finally an in vitro experimental setup that keeps an intestine alive for 6 hours was used to optimise the sample collection. The capsule collected 128 µL and 107 µL samples (which are sufficient quantities for microbiome analysis) from duodenual and ileal tissues of a sheep. The proposed robotic capsule has a potential to become a vital apparatus for clinicians to sample human and animal gut in the future.

Review article: Current status and future directions of ingestible electronic devices in gastroenterology

“…Various sampling devices have been described in prototype form, including a device able to collect small sample volumes in ex vivo and pig models, and a wireless device with magnetic actuation system, which is yet to be reported in vivo 136–140 . Active control over timing and localisation of sampling remains under development, and advances in robotic technology will undoubtedly overcome many of these current limitations in the future 141,142 . At this stage, despite multiple reports describing novel designs with claims of proof‐of‐concept, none have provided key peer‐reviewed data that move the concepts into the realm of clinical reality.…”

“… 136 , 137 , 138 , 139 , 140 Active control over timing and localisation of sampling remains under development, and advances in robotic technology will undoubtedly overcome many of these current limitations in the future. 141 , 142 At this stage, despite multiple reports describing novel designs with claims of proof‐of‐concept, none have provided key peer‐reviewed data that move the concepts into the realm of clinical reality. A logistical issue that is not likely to be overcome in the near future is the need to retrieve the excreted device in order to analyse the sampled material.…”

Modeling, analysis and control of robot–object nonsmooth underactuated Lagrangian systems: A tutorial overview and perspectives

“…Inertially driven machines are robots equipped with internal mechanisms which modify their inertial properties in order to produce motion thanks to the constraints, hence their gravity center is unactuated (they can be seen as extensions of underactuated robots like the acrobot and pendubot, see (C.1)). Contrarily to self-propelled capsules (section 3.8) the internal mechanisms are not vibro-impact systems, they aim at modifying the configuration in a cat-like way, i.e., controlling (1) (b) when λ n = 0, λ t = 0, while (1) (a) evolves freely, while some quantities are conserved, like the momentum for (49) (50) (hence significantly different from the robot part of ( 55) or (65), for instance). They may also be used in persistent contact with friction: the internal mechanism is meant to act on some velocities in order to produce suitable inertial forces (Coriolis or centripetal) which in turn act on the remaining coordinates so that motion is controlled.…”

“…Comments. Let us compare (65) with (66) or (67). While horizontal motion in persistent contact is possible for (66) or (67) (the robot's state enters friction), this is not possible for (65) if both contacts are in the all-sticking mode.…”

“…One aim of this article is to suggest that some cross-fertilization between apparently different subclasses of (1), could be beneficial. Apart from the classical application fields mentioned above, we may cite neurosciences [59,60,61], biomechanics and sports performance analysis [62,63], medicine [64,65], physical anthropology [66,67], psychology [68].…”