Micromotors Spontaneously Neutralize Gastric Acid for pH‐Responsive Payload Release

• Published in: Angewandte Chemie International Edition 2017-02, Vol.56 (8), p.2156-2161
• Main Authors: Li, Jinxing, Angsantikul, Pavimol, Liu, Wenjuan, Esteban‐Fernández de Ávila, Berta, Thamphiwatana, Soracha, Xu, Mingli, Sandraz, Elodie, Wang, Xiaolei, Delezuk, Jorge, Gao, Weiwei, Zhang, Liangfang, Wang, Joseph
• Format: Article
• Language: English
• Subjects: Acids; Acute toxicity; Animals; Cargo; Chemical propulsion; Delayed-Action Preparations - chemistry; drug delivery; Drug Liberation; Drugs; Encapsulation; Enzymes; Fluorescent Dyes - administration & dosage; gastric acid; Gastric Acid - chemistry; Gold - chemistry; Hydrogen ions; Hydrogen-Ion Concentration; Magnesium; Magnesium - chemistry; Mice; micromotor; Micromotors; Motor task performance; Motors; Mucous membrane; Neutralization; pH effects; Polymers - chemistry; Polymethacrylic Acids - chemistry; proton pump inhibitor; Proton pump inhibitors; Protons; responsive release; Rhodamines - administration & dosage; Side effects; Stomach; Toxicity
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201611774

The highly acidic gastric environment creates a physiological barrier for using therapeutic drugs in the stomach. While proton pump inhibitors have been widely used for blocking acid‐producing enzymes, this approach can cause various adverse effects. Reported herein is a new microdevice, consisting of magnesium‐based micromotors which can autonomously and temporally neutralize gastric acid through efficient chemical propulsion in the gastric fluid by rapidly depleting the localized protons. Coating these micromotors with a cargo‐containing pH‐responsive polymer layer leads to autonomous release of the encapsulated payload upon gastric‐acid neutralization by the motors. Testing in a mouse model demonstrate that these motors can safely and rapidly neutralize gastric acid and simultaneously release payload without causing noticeable acute toxicity or affecting the stomach function, and the normal stomach pH is restored within 24 h post motor administration. Magnesium‐based micromotors can autonomously and temporally neutralize gastric acid through efficient chemical propulsion in the gastric fluid by rapidly depleting the localized protons. The in vivo results demonstrate that these motors can safely and quickly neutralize gastric acid and simultaneously release a payload without causing noticeable acute toxicity or affecting the stomach function, and the normal stomach pH is restored within 24 hours post motor administration.