# A Low-Friction Capsule Robot with Drive–Control–Sensing Integration for Gastrointestinal Lesion Detection

## TL;DR

A low-friction capsule robot is developed to detect pH and temperature in the gastrointestinal tract for early disease diagnosis.

## Contribution

The capsule robot integrates drive, control, and sensing with a hydrogel skin to reduce friction and enable precise navigation.

## Key findings

- The hydrogel skin reduces surface friction by over 4 times and achieves a propulsion speed of 12.79 mm/s in a porcine small intestine.
- The capsule robot can continuously detect pH levels from 2 to 8 and temperatures from 36 to 40 °C.
- The robot enables multimodal locomotion through complex stomach and small intestine environments with integrated control and sensing.

## Abstract

pH and temperature in the gastrointestinal (GI) tract are correlated with many diseases, but patients suffer from the pain of traditional testing methods. Functionalized capsule robots for GI tract sensing offer a potential approach for early GI disease diagnosis. However, most capsule robots struggle with control and sensing integration. In addition, the friction encountered by capsule robots during navigation poses a challenge for their application. Here, a capsule robot with a low coefficient of friction is proposed to continuously detect pH and temperature. The hydrogel skin reduces the surface friction coefficient by more than 4 times and achieves an average propulsion speed of 12.79 mm s−1 in a living porcine small intestine. The capsule system enables continuous detection over a pH range of 2 to 8 and a temperature of 36 to 40 °C. We demonstrate capsule robots’ capability of multimodal locomotion through complex stomach and small intestine environment. It solves the problem that capsule robots used for sensing functions cannot be precisely controlled and achieves drive–control–sensing integration.