Water-powered self-propelled magnetic nanobot for rapid and highly efficient capture of circulating tumor cells

Ravindra D Wavhale,Bhausaheb V Tawade,Chinmay S Rahane,Yuvraj N Patil,Shashwat S Banerjee,Sandesh S Gawade,Govind P Chate,Kshama D Dhobale

doi:10.1038/s42004-021-00598-9

Abstract

Nanosized robots with self-propelling and navigating capabilities have become an exciting field of research, attributable to their autonomous motion and specific biomolecular interaction ability for bio-analysis and diagnosis. Here, we report magnesium (Mg)-Fe3O4-based Magneto-Fluorescent Nanorobot (“MFN”) that can self-propel in blood without any other additives and can selectively and rapidly isolate cancer cells. The nanobots viz; Mg-Fe3O4-GSH-G4-Cy5-Tf and Mg-Fe3O4-GSH-G4-Cy5-Ab have been designed and synthesized by simple surface modifications and conjugation chemistry to assemble multiple components viz; (i) EpCAM antibody/transferrin, (ii) cyanine 5 NHS (Cy5) dye, (iii) fourth generation (G4) dendrimers for multiple conjugation and (iv) glutathione (GSH) by chemical conjugation onto one side of Mg nanoparticle. The nanobots propelled efficiently not only in simulated biological media, but also in blood samples. With continuous motion upon exposure to water and the presence of Fe3O4 shell on Mg nanoparticle for magnetic guidance, the nanobot offers major improvements in sensitivity, efficiency and speed by greatly enhancing capture of cancer cells. The nanobots showed excellent cancer cell capture efficiency of almost 100% both in serum and whole blood, especially with MCF7 breast cancer cells.

Highlights

Nanosized robots with self-propelling and navigating capabilities have become an exciting field of research, attributable to their autonomous motion and specific biomolecular interaction ability for bio-analysis and diagnosis
The nanobots were prepared by fabricating a hemispherical shell of Fe3O4 on Mg nanoparticles and by selectively assembling multiple components viz; (i) anti-Epithelial cell adhesion molecule (EpCAM) monoclonal antibody (Ab)/transferrin (Tf) for targeting cancer cells, (ii) cyanine 5 NHS (Cy5) dye for particle labeling, (iii) fourth generation (G4) dendrimer for multiple conjugation and (iv) glutathione (GSH) linker by chemical conjugation onto one side of Mg nanoparticle using the parafilm method
Upon mild heating at 40 oC, the Mg nanoparticles were partially embedded into the parafilm and the remaining area of the nanoparticles was exposed for subsequent fabrication processes

Summary

Introduction

Nanosized robots with self-propelling and navigating capabilities have become an exciting field of research, attributable to their autonomous motion and specific biomolecular interaction ability for bio-analysis and diagnosis. With continuous motion upon exposure to water and the presence of Fe3O4 shell on Mg nanoparticle for magnetic guidance, the nanobot offers major improvements in sensitivity, efficiency and speed by greatly enhancing capture of cancer cells. Fabrication of versatile water driven micro/nanobots possessing advanced mobility and ability to perform complex biological functions, such as featuring specific cell recognitions in shortest time frame, represents an exciting yet challenging task in the field of nanobiotechnology[9]. In light of these advantages, we present smart self-propelled Mg-based Janus nanobots, which can self-propel in blood without any other additives and can selectively isolate cancer cells. The efficient cargo-towing ability of such selfpropelled nanobot, along with precise motion control can lead to medical diagnostic microchips driven via sustainable endogenous chemical activity

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Conclusion