Helical Nanomachines for Fast Mechanical Mapping of Heterogeneous Environments

TL;DR

This paper introduces helical nanomachines controlled by magnetic fields to rapidly and precisely map local rheological properties, including viscosity and elasticity, in complex heterogeneous environments with high spatial and temporal resolution.

Contribution

It presents a novel technique using magnetically controlled helical nanomachines for detailed rheological mapping of complex fluids, surpassing existing microrheological methods.

Findings

Nanomachines accurately measure local viscosity and elasticity.

Motion sensitivity varies with fluid rheological properties.

High-resolution mapping of heterogeneous environments achieved.

Abstract

Artificial micro and nano machines have been envisioned and demonstrated as potential candidates for variety of applications, ranging from targeted drug or gene delivery, cell manipulation, environmental sensing and many more. Here, we demonstrate the application of helical nanomachines that can measure and map the local rheological properties of a complex heterogeneous environment. The position of the helical nanomachine was controlled precisely using magnetic fields, while the instantaneous orientation provided an estimation of the viscosity of the surrounding medium with high spatial and temporal accuracy. Apart from providing viscosity estimates in purely viscous and viscoelastic media with shear rate independent viscosity (Boger fluids), their motion was also found to be extremely sensitive to fluid elasticity. Taken together we report a promising new technique of mapping the rheological properties of a complex fluidic environment by helical nanomachines with high spatial and temporal resolutions, a functionality that goes beyond the capabilities of existing passive and active microrheological methods.