Micromotors Spontaneously Neutralize Gastric Acid for pH‐Responsive Payload Release

Abstract

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. Herein, we report on a new microdevice, consisting of magnesium-based micromotors that 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, the in vivo results 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, with the normal stomach pH restored within 24 h post motor administration.

Self‐Propelled Micro/Nanomotors for Sensing and Environmental Remediation

“…There are reports on preparation of self‐degrading and green micro/nanomotors from environmentally friendly materials such as Mg, Pt, or Zn which utilize pure water as fuel . The Mg and Zn based micromotors used the water for generation of hydrogen gas bubbles and consequent motions . Enzyme‐based micro/nanomotor which driven by biocompatible fuels such as glucose and urea is another candidates for application in sensing and biomedical applications, but due to their sensitivity to environmental parameters their application for water and environmental remediation is limited.…”

Fabrication of Self‐Propelled Micro‐ and Nanomotors Based on Janus Structures

“…Additionally,t he speed of the micromotor decreased with increasing salt concentration because high ionic strength resulted in larger bubble sizes and fewer bubbles. [6] These Janus micromotors were demonstrated to safely and quickly deplete excess gastric acid and released rugs. [12] The Mg microparticles weres pread in am onolayer on the glass slide.…”

“…[13b] To endow the Mg/Au Janus micromotor with more functions, they could also be coated with ap H-sensitive drugloadedp olymeric layer. [6] These Janus micromotors were demonstrated to safely and quickly deplete excess gastric acid and released rugs. Mg/Ag Janus micromotorss howed much better antibacterialp roperties comparedw ith those of static Janus particles.…”

“…In 2002, the group of Whitesides developed the first artificial motor on the centimeter scale, which could move autonomously through the decomposition of H 2 O 2 fuel. [6] Benefitting from enhanced motion manipulation in the past decade, [7] motor systemsc an act as tiny robots that make it possible to perform specific tasks inside our body. Later,i n2 004, bimetallic motors consisting of platinum and gold segmentsw ere reported upon successfully scaling down the size of motors to the micrometer level.…”

Microfluidic Lithography of Bioinspired Helical Micromotors

“…[1][2][3][4][5] In the past decade,m any artificial micromotors with various structures and properties have been developed. [6][7][8][9][10][11] Among them, the artificial micromotors with helical microstructures have attracted increasing attention because they can mimic the function of amazing natural systems,such as the bacterial flagellum propulsion. [12][13][14][15] To generate helical micromotors, many nanofabrication processing techniques have been employed, including self-scrolling,s urface patterning,g lancing angle deposition, three-dimensional (3D) laser writing or lithography,b iotemplated chemical plating,a nd so on.…”