REMUS100 AUV with an integrated microfluidic system for explosives detection

Abstract

Quantitating explosive materials at trace concentrations in real-time on-site within the marine environment may prove critical to protecting civilians, waterways, and military personnel during this era of increased threat of widespread terroristic activity. Presented herein are results from recent field trials that demonstrate detection and quantitation of small nitroaromatic molecules using novel high-throughput microfluidic immunosensors (HTMI) to perform displacement-based immunoassays onboard a HYDROID REMUS100 autonomous underwater vehicle. Missions were conducted 2-3 m above the sea floor, and no HTMI failures were observed due to clogging from biomass infiltration. Additionally, no device leaks were observed during the trials. HTMIs maintained immunoassay functionality during 2 h deployments, while continuously sampling seawater absent without any pretreatment at a flow rate of 2 mL/min. This 20-fold increase in the nominal flow rate of the assay resulted in an order of magnitude reduction in both lag and assay times. Contaminated seawater that contained 20-175 ppb trinitrotoluene was analyzed.

Detection of Explosives in a Dynamic Marine Environment Using a Moored TNT Immunosensor

“…This demonstration highlights the numerous advantages of the immunosensor compared to other field deployed TNT sensing platforms: (1) higher sensitivity (parts-per-trillion to ppb levels) and (2) longevity (>18 h of continuous operation) which far exceeds previously published reports to our knowledge [21,22], (3) increased flow rates (up to 9 mL/min) resulting in improved response times (12 s) which compares favorably to many electrochemical detection methods, (4) requires no sample preconcentration which as reported by Trammell and colleagues was necessary to improve sensor sensitivity for trace level detection [23] and most importantly (5) field-durability.…”

“…Each response shown corresponds to a plume simulation of 1–100 ppb TNT emanating from the plume generator where the released TNT was 1.0 ppm. Previous field experiments where the immunosensor payload was integrated with a REMUS AUV to transport and assess TNT composition in seawater suggested that the dilution effect of the seawater with a 2.54 cmseparation between the immunosensor inlet and plume release port could be as high as 100-fold [22]. …”

A High Aspect Ratio Bifurcated 128-Microchannel Microfluidic Device for Environmental Monitoring of Explosives

“…Demonstrated within this report is a 128-microchannel microfluidic device that combines intricate architectural designs and biomolecular specificity of an antibody specific for TNT for trace level TNT detection. Evolution of the displacement immunoassay format for TNT from porous membranes [ 23 ], fused-silica microcapillaries [ 24 , 25 ] to microchanneled microfluidic devices [ 20 ] signifies the importance and advantages of maintaining high surface area to volume ratios leading to increased antibody-antigen interactions. Characterization of the 128-microchanneled microfluidic device using COMSOL fluid flow simulations provided greater insight into the fluid dynamics and flow processes.…”

“…The fluorescence displacement immunoassay detection system consisted of the following components: (1) fluorescence spectrofluorometer-Model FP-2020 Plus—was used to measure the displaced fluorescence analog (Cy5-amine–TNB) from the binding pocket of the monoclonal antibody; (2) Rheodyne low pressure three-way-valve injector loop (100 μL) for sample introduction; and (3) two reciprocating pumps (Applied Biosystems, Inc., Foster, CA, USA) for continuous flow at a controlled flow rate (1.0 mL/min). As TNT is introduced into the continuous flow system, preferential binding occurs between the anti-TNT to TNT resulting in the displacement or release of Cy5-amine-TNB from the proteins binding site [ 20 ]. A resultant fluorescence signal (peak) over background is measured and correlated to the TNT concentration.…”

On the Dynamic Analysis of a Novel Snake Robot: Preliminary Results

“…Mobile robots are meaningful examples of service robots, that are implementing novel key technologies. Mobile robots can be classified by the environment in which they travel, for example UGVs (Unmanned Ground Vehicles) [12], UAVs (Unmanned Aerial Vehicles) [10] and AUVs (Autonomous Underwater Vehicles) [2], or by the device that they use to move as legged robot [11,3], wheeled robot [19,3] and tracked robot [3], or by the work that they do as transportation, mapping, cleaning, assistance and so forth.…”