Nanoparticle Chemical Sensors for UUXO Detection

Christian Schoen, PhDVP CTO

Concurrent Analytical Inc.

Partnership Workshop: Robotic Technology To Support Underwater Unexploded Ordnance (UUXO) Ops

Friday, 10 Oct Hilton Hawaiian Village, Waikiki

CEROS Funded Effort

• In conjunction with Sea Engineering, funded by CEROS to develop UUXO detection systems

• Kaho’olawe coast

Define Goals• Analyzed seawater off

Kaho’olawe• Proximal to leaky

explosive– Was able to measure 40

ppm close, 1 ppm @ 5 meters

– 1 ppt @ 1000 meters?• Chemical radiation from

explosives does not occur in a hemispherical pattern

UUXO plume

How sensitive is this?

• Sharks detect blood in seawater at 100 ppmillion

• 1 ppm = 1 drop in 50 liters

Comparison

• One part per trillion (1 ppt) is a proportion equivalent to one drop of water diluted into twenty olympic size swimming pools

Detection System Requirements

• Extremely sensitive (~ppt)• Fast (seconds)• Corrosion resistant• Biofouling resistant• Low power consuming/ remote stand alone operation• Directional?

Solution: Optical Transducer• Optical transducer based on antibody/antigen mechanisms• Benefits:

– Antibody/antigen interaction is very sensitive (used in diagnostic assays at similar sensitivity requirements)

– Optical systems can be made to be robust in ocean environments

– Optical systems can be made to be remotely operable/low power

• Disadvantages:– Not directional – passive system

UUXOOptical Transducer

Gold Nanorods Geometrically-tunable

plasmon resonance throughout visible/NIR

Highly monodisperse, scalable manufacturing method

Potential as multimodal agents for sensors

Polymer coated gold is extremely robust in corrosive environments

Simple

How Sensitive/Selective?

• Work to ppt • Using Raman labels is 1,000,000x better• Can work with multiple target concurrently• Problem:

SprayjetTM Solution

• Current SOTA is 30 minutes to 2 days• For ppt, sprayjet can work in a few seconds at many

ml per sec.

How much quicker?

Conclusion

• Optical Transducers, particularly plasmonic gold nanorods, can be used as a robust sensor for UUXOs