Light‐triggered Janus nanomotor for targeting and photothermal lysis of pathogenic bacteria

Abstract

The rapid photothermal lysis of Escherichia coli O157:H7 treated with light‐triggered Janus nanomotors was visualized by Hilbert differential contrast transmission electron microscopy (HDC‐TEM). The extraordinary advantage of this high‐resolution microscopic technique was that it revealed the detailed ultrastructure alterations of the treated cells at a state close to their native one. The micrographs demonstrated that Janus nanomotors (mesoporous silica nanoparticles with gold hemisphere and half‐capped with cysteamine) were able to target and bind to the pathogenic E. coli. The biorecognition reaction proceeded at slightly acid pH thankful to the formed electrostatic adhesion between positively charged amino groups on nanoparticles surface and the negatively charged cell envelope. The exposure of labeled cells to near infrared laser irradiation leaded to occurrence of effective photothermal damage of their plasma membranes, which was enough strong to lyse bacteria. It was because of the overheating obtained by the photon‐to‐thermal conversion reaction generated by the surface plasmon resonance response of Janus nanomotors. The good efficiency of photothermal lysis to inactivate E. coli O157:H7 was confirmed by staining with LIVE/DEAD viability kit and quantification of the few survived cells in epifluorescence microscope. Furthermore, HDC‐TEM images of ice‐embedded inhibited bacteria documented the labeling, membrane disruptions and lysis due to the designed operation of Janus nanomotors. The reported microscopic technique provides a novel strategy for developing of Janus nanomachines as promising platform for nondrug treatment and defeating of antibiotic‐resistant pathogenic microorganisms.

Janus Micro/Nanorobots in Biomedical Applications

“…Reproduced with permission. [ 88 ] Copyright 2021, Wiley Periodicals LLC. D) Dual‐propelled lanbiotic based Janus micromotors by catalytic and magnetic engines for selective inactivation of pathogenic bacteria biofilms.…”

“…C) Light-triggered Janus nanomotor made of mesoporous silica nanospheres coated with gold hemisphere for targeting and photothermal lysis of pathogenic E. coli. Reproduced with permission [88]. Copyright 2021, Wiley Periodicals LLC.…”

Light‐activated oxidize‐mimicking nanozyme for inhibition of pathogenic Escherichia coli

“…Single freshly revived colonies of E. coli O157:H7 were prepared as described in the reference (Loukanov, 2021). The microbial suspension was cultured in 10 ml of nutrient broth (NB) medium at 37 C and 100 rpm in a shaking incubator for overnight.…”

Research progress in the application of colloidal motors for precision medicine

“…Loukanov et al reported a cysteamine functionalized colloidal motor that targeted and bound to Escherichia coli by electrostatic adhesion. 55 Under near-infrared irradiation, the Janus colloidal motor achieved drug-free sterilization by thermally inducing rupture of the plasma membrane causing irreparable cell damage. In summary, colloidal motors can achieve drug-free antibacterial activity by direct or indirect action of their own functions.…”

“…45,[49][50][51][52] At present, functionalized colloidal motors possess numerous therapeutic functions, like anti-cancer, anti-bacterial, antiinflammation, hypoglycemic, immune activation and hemostasis functions. These therapeutic functions provide a variety of ways for colloidal motors to treat diseases, including drug delivery, 32 enhancement of immune cells, 53 alteration of the cell microenvironment 54 and the use of physical lethal agents 55 (Scheme 1). Meanwhile, the biosensing and other functions of colloidal motors have also been gradually developed, which provides a new platform for the rapid diagnosis and treatment of diseases.…”