A Caltech Library Service

Motion-based threat detection using microrods: experiments and numerical simulations

Ezhilan, Barath and Gao, Wei and Pei, Allen and Rozen, Isaac and Dong, Renfeng and Jurado-Sanchez, Beatriz and Wang, Joseph and Saintillan, David (2015) Motion-based threat detection using microrods: experiments and numerical simulations. Nanoscale, 7 (17). pp. 7833-7840. ISSN 2040-3364.

[img] PDF - Published Version
See Usage Policy.

[img] Video (QuickTime) (Movie 1) - Supplemental Material
See Usage Policy.

[img] Video (QuickTime) (Movie 2) - Supplemental Material
See Usage Policy.


Use this Persistent URL to link to this item:


Motion-based chemical sensing using microscale particles has attracted considerable recent attention. In this paper, we report on new experiments and Brownian dynamics simulations that cast light on the dynamics of both passive and active microrods (gold wires and gold–platinum micromotors) in a silver ion gradient. We demonstrate that such microrods can be used for threat detection in the form of a silver ion source, allowing for the determination of both the location of the source and concentration of silver. This threat detection strategy relies on the diffusiophoretic motion of both passive and active microrods in the ionic gradient and on the speed acceleration of the Au–Pt micromotors in the presence of silver ions. A Langevin model describing the microrod dynamics and accounting for all of these effects is presented, and key model parameters are extracted from the experimental data, thereby providing a reliable estimate for the full spatiotemporal distribution of the silver ions in the vicinity of the source.

Item Type:Article
Related URLs:
URLURL TypeDescription
Gao, Wei0000-0002-8503-4562
Dong, Renfeng0000-0001-7590-5750
Additional Information:© 2015 The Royal Society of Chemistry. Received 21st October 2014, Accepted 23rd March 2015. This project received support from the Defense Threat Reduction Agency-Joint Science and Technology Office for Chemical and Biological Defense (Grant no. HDTRA1-13-1-0002). D. S. acknowledges support from NSF grant CBET-1151590. W. G. is a HHMI International Student Research fellow. R. D. acknowledges financial support from the China Scholarship Council (CSC). B. J.-S. acknowledges support from the People Programme (Marie Curie Actions) of the EU 7th Framework Programme (FP7 2007-2013) under REA Grant PIOF-GA-2012-326476. The authors greatly thank Mr Yuri Fedorak for assistance with the preparation of figures.
Funding AgencyGrant Number
Defense Threat Reduction Agency (DTRA)HDTRA1-13-1-0002
China Scholarship CouncilUNSPECIFIED
Marie Curie FellowshipPIOF-GA-2012-326476
Issue or Number:17
Record Number:CaltechAUTHORS:20171011-144933109
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:82293
Deposited By: Ruth Sustaita
Deposited On:12 Oct 2017 16:23
Last Modified:09 Mar 2020 13:18

Repository Staff Only: item control page