PH Sensor-Embedded Magnetically Driven Capsule for H. pylori Infection Diagnosis

Abstract

The Campylobacter-like organism (CLO) test is the most commonly employed test for diagnosing <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Helicobacter pylori</i> ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">H. pylori</i> ) infection in the stomach. Since the CLO test is an invasive method, minimally invasive methods have been proposed. However, the proposed methods exhibit relatively low specificity and sensitivity. In this letter, a novel <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">H. pylori</i> infection diagnosis method that uses a pH sensor-embedded magnetically driven capsule is proposed. The proposed method adopts the principle of the CLO test to diagnose <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">H. pylori</i> infection minimally invasively. The capsule comprises two chambers to sample gastric juice, and a pH sensor is embedded inside each chamber. Therefore, <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">H. pylori</i> infection can be diagnosed using the urea hydrolysis property of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">H. pylori</i> and a pH sensor embedded in the chambers of the capsule. In addition, the capsule can be magnetically actuated using an external magnetic field owing to its neodymium-magnet. The performance of the proposed capsule was evaluated in several aspects. First, the sensing ability of the fabricated pH sensor was verified using a pH buffer solution. Second, the magnetic actuation capacity of the capsule was evaluated using a 6-coil electromagnetic actuation (EMA) system. Third, the gastric juice sampling and pH-sensing capabilities of the assembled capsule were evaluated using a phantom test. Finally, the ability to diagnose <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">H. pylori</i> infection was validated using an ex vivo test. Consequently, this letter highlights the potential feasibility of establishing an <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">H. pylori</i> infection diagnosis method using a pH sensor-embedded magnetically driven capsule.