Ingestible capsule systems continue to evolve to overcome drawbacks associated with traditional gastrointestinal (GI) diagnostic and therapeutic processes, such as limitations on which sections of the GI tract can be accessed or the inability to measure local biomarker concentrations. We report an integrated capsule sensing system, utilizing a hybrid packaging scheme coupled with triglyceride film-coated capacitive sensors, for measuring biochemical species present in the duodenum, such as pancreatic lipase and bile acids. The system uses microfabricated capacitive sensors interfaced with a Bluetooth low-energy (BLE)-microcontroller, allowing wireless connectivity to a mobile app. The triglyceride films insulate the sensor surface and react either with 0.01–1 mM lipase via hydrolysis or 0.07–7% w/v bile acids via emulsification in simulated fluids, leading to measurable changes in capacitance. Cross reactivity of the triglyceride films is evaluated in both phosphate buffered saline (PBS) as well as pancreatic trypsin solutions. The film morphology is observed after exposure to each stimulus to better understand how these changes alter the sensor capacitance. The capsule utilizes a 3D-printed package coated with polymers that remain intact in acid solution (mimicking gastric conditions), then dissolve at a duodenum-mimicking neutral pH for triggered opening of the sensing chamber from which we can subsequently detect the presence of pancreatic lipase. This device strategy represents a significant step towards using embedded packaging and triglyceride-based materials to target specific regions of the GI tract and sensing biochemical contents for evaluating gastrointestinal health. 
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                            Video Capsule Endoscopy and Ingestible Electronics: Emerging Trends in Sensors, Circuits, Materials, Telemetry, Optics, and Rapid Reading Software
                        
                    
    
            Real-time monitoring of the gastrointestinal tract in a safe and comfortable manner is valuable for the diagnosis and therapy of many diseases. Within this realm, our review captures the trends in ingestible capsule systems with a focus on hardware and software technologies used for capsule endoscopy and remote patient monitoring. We introduce the structure and functions of the gastrointestinal tract, and the FDA guidelines for ingestible wireless telemetric medical devices. We survey the advanced features incorporated in ingestible capsule systems, such as microrobotics, closed-loop feedback, physiological sensing, nerve stimulation, sampling and delivery, panoramic imaging with adaptive frame rates, and rapid reading software. Examples of experimental and commercialized capsule systems are presented with descriptions of their sensors, devices, and circuits for gastrointestinal health monitoring. We also show the recent research in biocompatible materials and batteries, edible electronics, and alternative energy sources for ingestible capsule systems. The results from clinical studies are discussed for the assessment of key performance indicators related to the safety and effectiveness of ingestible capsule procedures. Lastly, the present challenges and outlook are summarized with respect to the risks to health, clinical testing and approval process, and technology adoption by patients and clinicians. 
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                            - Award ID(s):
- 1556370
- PAR ID:
- 10334506
- Date Published:
- Journal Name:
- Advanced Devices & Instrumentation
- Volume:
- 2021
- ISSN:
- 2767-9713
- Page Range / eLocation ID:
- 1 to 30
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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