Rats’ Whiskers Inspire a Tactile Sensing System for Safer, More Informative Endoscopy
Rats may be helping engineers solve one of the most persistent problems in gastrointestinal medicine: how to detect and interpret tissue that an endoscope cannot clearly see. Researchers have developed a bionic multichannel whisker system designed to give future endoscopic instruments a form of artificial touch. Inspired by the way rodents use their whiskers to navigate dark, narrow environments, the technology converts tiny mechanical interactions between flexible sensor “whiskers” and tissue or other surfaces into electrical signals. The resulting data could eventually help endoscopists identify subtle abnormalities, reconstruct local tissue geometry, and recognize potentially dangerous levels of contact force during procedures.
“Rats navigate and perceive their environment largely through whisker-mediated touch, especially in poorly lit, confined spaces,” explains Professor Lo. “We asked: could we replicate that sensory capability to help endoscopists feel what they cannot see?” Unlike conventional endoscopy, which depends primarily on optical images, the proposed system is designed to sense physical properties directly. Its slender whisker shafts are made from 0.16-millimeter acupuncture needles, each equipped with a strain gauge at its base. When a whisker bends after contacting a surface, the strain gauge experiences a change in mechanical strain. That change is translated into an electrical signal, allowing the system to measure contact dynamics without relying on visual information alone.
The prototype contains eight independently monitored sensing channels arranged in two complementary configurations. A four-whisker array positioned underneath the distal tip is intended for detailed interrogation of surfaces, allowing the device to scan across material and detect changes in texture or height. A second four-whisker arrangement is mounted around the perimeter and angled at 20 degrees to detect radial collisions. Together, the configurations are designed to support two different endoscopic tasks: controlled, short-range sensing of suspicious areas and continuous monitoring of contact during navigation through a confined anatomical passage. The spatial arrangement of the whiskers allows the system to record not only whether contact occurs, but also where and how it occurs around the instrument.
One of the central engineering problems was ensuring that all eight channels responded consistently. Manufacturing tolerances, slight differences in the whiskers, strain gauges, adhesive joints, and mounting geometry can cause each channel to have a different baseline signal and sensitivity. Without correction, these variations could be mistaken for genuine differences in tissue shape or force. To address the problem, the team developed an affine transformation-based calibration framework supported by robust fitting. The method compensates for gain and offset mismatches between channels while limiting the computational burden. After calibration, signals from different whiskers can be compared more reliably, improving the interpretability of tasks such as three-dimensional shape reconstruction and force estimation.
The researchers first tested whether the artificial whiskers could distinguish surface textures. The array was scanned across five grades of sandpaper, ranging from coarse P80 to fine P2000. Analyses in the time domain, frequency domain, and combined time-frequency domain revealed clear differences among the surfaces. Coarser textures generated signals with larger amplitudes and lower dominant frequencies, reflecting more pronounced mechanical disturbances as the whiskers passed over the abrasive surface. Finer textures produced more stable responses and higher-frequency signal components. This ability to separate surfaces according to their microstructural characteristics is important because biological abnormalities may alter the mechanical and topographical properties of mucosal tissue even when visual differences are extremely subtle.
In a second experiment, the system was used to reconstruct the shapes of three-dimensional printed benchmarks containing wavy, rectangular, and triangular profiles. The test objects included stepped height changes as small as 1.5 millimeters, representing the kind of low-profile geometric variation that could be relevant to early protrusions, narrowing, or other local structural changes. Before calibration, the reconstructed profiles showed substantial disagreement with the known ground truth. The errors reflected both channel-to-channel variability and imperfections in platform leveling. Once the affine calibration was applied, the mean Pearson correlation between the reconstructed and actual profiles increased from 0.081 to 0.796. At the same time, the mean absolute error along the Z axis fell from 2.22 millimeters to 0.81 millimeters, a reduction of approximately 63 percent. “We can now recover local geometric features at millimetre scale, which is clinically meaningful for detecting low-profile protrusions or early narrowing,” emphasizes Professor Yeatman.
The third experiment examined whether the whiskers could act as force sensors during instrument contact. For this test, the researchers used a 15-millimeter-diameter peripheral mount and calibrated each channel against an ATI force sensor. The results showed millinewton-level errors and Pearson correlation coefficients above 0.91 for every channel. In a handheld colon phantom, the system generated cylindrical force maps that displayed how contact was distributed around the simulated intestinal wall. During two simulated endoscopic insertion trials, the whiskers differentiated high-collision events from smooth advancement. When the flexible shafts were pushed backward against the wall, the system recorded a distinctive increase in contact loading. Such measurements could provide an early warning of excessive force, potentially helping clinicians avoid tissue trauma or perforation during navigation.
The electronics were designed to capture very small signals generated by the flexible whiskers. Each strain gauge operates within a Wheatstone bridge circuit connected to a preamplifier, while a 24-bit sigma-delta analog front end digitizes the measurements before wireless transmission. The reported noise level was exceptionally low, with an RMS value of 0.41 microvolts and a peak-to-peak value of 2.91 microvolts. This low noise floor is important because the system must distinguish small changes in strain caused by light contact from electrical interference and mechanical vibration. The dominant resonance of the prototype was approximately 69 hertz, well above the task-relevant frequency range observed under the scanning conditions used in the experiments. That separation reduces the risk that the system’s own structural dynamics will obscure the tactile signals it is intended to measure.
Despite the promising laboratory results, the technology is not yet ready for routine clinical use. The current distal mount has an outer diameter of 15 millimeters, making it too large for straightforward integration with standard gastrointestinal endoscopes. The researchers plan to reduce the size through microelectromechanical systems-based strain-gauge fabrication, tighter packaging, and modular or reconfigurable mounting strategies. Future studies will also need to establish whether the materials are biocompatible, whether the structure can withstand repeated sterilization, and whether calibration remains stable after prolonged use. The system must ultimately be tested in more realistic anatomical models and, later, in carefully controlled clinical studies before its diagnostic value can be determined.
The researchers emphasize that artificial whiskers are intended to complement, rather than replace, endoscopic vision. “Our system is not a replacement for vision,” says Professor Lo. “It is a complementary tactile layer that could be integrated into future robotic endoscopes—providing force-aware feedback during navigation and contact-informed interrogation of visually ambiguous regions.” The long-term concept combines tactile sensing with electromagnetic, optical, or fiber-based positional tracking so that each signal can be linked to a precise location inside the body. Learning-based algorithms could then be trained to associate patterns of texture, shape, and force with clinically relevant tissue states. The study, titled “A Bionic Multichannel Whisker System for Assisting Endoluminal Intervention,” establishes the hardware and calibration framework for that approach. Published in Cyborg and Bionic Systems on August 8, 2026, the work suggests that the next generation of endoscopic instruments may not only show physicians what lies ahead, but also provide a measured sense of how the body feels.
Subject of Research:
A bionic multichannel whisker sensing system for tactile gastrointestinal endoscopy, including texture discrimination, millimeter-scale shape reconstruction, and radial force monitoring.
Article Title:
“A Bionic Multichannel Whisker System for Assisting Endoluminal Intervention”
News Publication Date:
Not provided.
Web References:
DOI: https://doi.org/10.34133/cbsystems.0616
References:
Liping Dong, Xingxuan Zhang, Meng Li, Yi Li, Jingyi Guo, Shaorong Lu, Zhenyu Peng, Chenxi Zheng, Yufei Hui, Xiaoping Shao, Feiyan Wang, Weikang Jiang, Maoyao Li, Xianshuai Wu, Xu Guo, Yingchuan Li, Yuanyi Zheng, and Liping Zhang. “A Bionic Multichannel Whisker System for Assisting Endoluminal Intervention.” Cyborg and Bionic Systems, published August 8, 2026.
Image Credits:
Eric M. Yeatman, Department of Electrical and Electronic Engineering, Faculty of Engineering, Imperial College London.
Keywords
Bionic whiskers, tactile sensing, endoscopy, gastrointestinal robotics, medical robotics, strain gauges, force sensing, texture discrimination, shape reconstruction, endoluminal intervention, artificial touch, robotic surgery, Cyborg and Bionic Systems
Tags: artificial touch in medical devicesbio-inspired engineering for healthcarebio-inspired sensory technologybionic multichannel whisker systemflexible sensor arrays for medical applicationsforce feedback in endoscopic diagnosticsimproving safety in endoluminal interventionsminimally invasive gastrointestinal proceduresrobotic endoscopic instrumentstactile sensing for endoscopytissue interaction detectionwhisker-based navigation in medical tools
