Polypyrrole-Based Nanorobots Powered by Light and Glucose for Pollutant Degradation in Water

Abstract

Novel photoactive and enzymatically active nanomotors were developed for efficient organic pollutant degradation. The developed preparation route is simple and scalable. Light-absorbing polypyrrole nanoparticles were equipped with a bi-enzyme [glucose oxidase/catalase (GOx/Cat)] system enabling the simultaneous utilization of light and glucose as energy sources for jet-induced nanoparticle movement and active radical production. The GOx utilizes glucose to produce hydrogen peroxide, which is subsequently degraded by Cat, resulting in the generation of active radicals and/or oxygen bubbles that propel the particles. Uneven grafting of GOx/Cat molecules on the nanoparticle surface ensures inhomogeneity of peroxide creation/degradation, providing the nanomotor random propelling. The nanomotors were tested for their ability to degrade chlorophenol, under various experimental conditions, that is, with and without simulated sunlight illumination or glucose addition. In all cases, degradation was accelerated by the presence of the self-propelled nanoparticles or light illumination. Light-induced heating also positively affects enzymatic activity, further accelerating nanomotor diffusion and pollutant degradation. In fact, the chemical and photoactivities of the nanoparticles led to more than 95% removal of chlorophenol in 1 h, without any external stirring. Finally, the quality of the purified water and the extent of pollutant removal were checked using an eco-toxicological assay, with demonstrated significant synergy between glucose pumping and sunlight illumination.

Self-Assembly of a 3D Hollow BiOBr@Bi-MOF Heterostructure with Enhanced Photocatalytic Degradation of Dyes

“…Photocatalytic degradation has been considered to be an effective and promising method for removing organic dyes from industrial wastewater, − where the separation of photogenerated charge carriers and the effective absorption of dye molecules are crucial in the degradation processes . Thanks to their strong ability to capture dye molecules, high surface area, flexible skeleton structure, diversified functions, and intriguing tailorable features, metal–organic frameworks (MOFs) seem to be a promising porous photocatalyst in realizing the efficient degradation of dyes, − while MOFs themselves exhibit very poor transmission/separation efficiency of photogenerated charge carriers and limited visible light adsorption ability. − Consequently, several efficient inorganic semiconductor/MOF-based heterojunctions, such as TiO 2 @MOF, CdS–NRs/MOF, g-C 3 N 4 /MOF, and BiOBr/MIL-53­(Fe), − were developed to significantly improve their photocatalytic performance.…”

Towards micromachine intelligence: potential of polymers

“…However, the replacement of toxic fuel needed for their actuation, scale-down of their dimension to the nanometer scale, and their formulation using scalable synthetic methods for large-scale environmental protection are still challening. 43 Recently, the scientific community has exploited the use of biofriendly biomolecules (e.g., glucose, lactose, and urea) to propel polymeric microtubes or to design new hybrid nanorobots that utilize the light-responsiveness of conductive polymers. For instance, Lyutakov et al reported novel light-absorbing PPy spherical nanoparticles with a bi-enzymatic system glucose oxidase/catalase (GOx/Cat) grafted on their surfaces enabling the concomitant use of light and GOx/Cat as energy sources for jet-induced nanoparticle movement.…”

“…At the same time, reactive oxygen species (ROS) are produced to effectively degrade of organic pollutants in water. 43…”

Powering and Fabrication of Small-Scale Robotics Systems

“…I Schematic representation of the sequent process of nanoparticle preparation, activation, and enzyme immobilization. (Adapted from [ 43 ]. Copyright © 2021 American Chemical Society.)…”

“…The swimmers were propelled by bubble propulsion using hydrogen peroxide as a fuel and upon irradiation with UV or visible light. Lyutakov and co-workers have recently reported on glucose-fueled sun light-driven polypyrrole-based nanoswimmers [ 43 ]. Two types of nanorobots were fabricated using a wet chemistry polymerization approach in which pyrrole and 1-(2-carboxyethyl)-pyrrole were used as monomers and mixed in a solution containing iron(III) chloride as oxidant and polyvinyl alcohol.…”