Spinach plants engineered to detect explosives in groundwater
It gives Popeye special powers and now it's been given its own. Scientists in the US have nano-engineered spinach plants to detect explosive molecules and send this information via an infrared signal that can be recorded by smartphone cameras. The spinach leaves were functionalised with nanoparticles that can detect nitroaromatic molecules like TNT. Plants continually draw up water and nutrients from the soil using their roots, but contaminants in the groundwater are often taken into the plant as well. The nanoparticles in the leaves act as sensors, and fluoresce different amounts based on how much of the contaminant is present. Because this fluorescence is infra-red, it can be recorded by smartphones, creating wireless real-time chemical monitoring. According to researchers from MIT who led the study, by modifying the molecule attached to the nanoparticles, the sensors can be adapted for different contaminants.
Journal/conference: Nature Materials
Organisation/s: Massachusetts Institute of Technology, USA
Funder: The nitroaromatic detection work using B-SWCNTs and P-SWCNTs were supported by
the US Army Research Office under contract W911NF-13-D-0001. The graphene work
was supported by the US Department of Energy, Office of Science, Basic Energy Sciences
under Award grant number DE-FG02-08ER46488 Mod 0008. M.H.W. is supported on a
graduate fellowship by the Agency of Science, Research and Technology Singapore.
J.P.G. was supported by National Science Foundation Postdoctoral Research Fellowship
in Biology under Grant No. 1103600. V.B.K. is supported by The Swiss National Science
Foundation (project No. P2ELP3_162149). The authors wish to thank Melanie Gronick
(MIT media) for her invaluable assistance in producing the Supplementary Movie 3 and
also G. Verma for helpful discussions.
Nitroaromatic detection and infrared communication from wild-type plants using plantnanobionics
Plant nanobionics aims to embed non-native functions to plants by interfacing them with specifically designed nanoparticles. Here, we demonstrate that living spinach plants (Spinacia oleracea) can be engineered to serve as self-powered preconcentrators and autosamplers of analytes in ambient groundwater and as infrared communication platforms that can send information to a smartphone. The plants employ a pair of near-infrared fluorescent nanosensors—single-walled carbon nanotubes (SWCNTs) conjugated to the peptide Bombolitin II to recognize nitroaromatics via infrared fluorescent emission, and polyvinyl-alcohol functionalized SWCNTs that act as an invariant reference signal—embedded within the plant leaf mesophyll. As contaminant nitroaromatics are transported up the roots and stem into leaf tissues, they accumulate in the mesophyll, resulting in relative changes in emission intensity. The real-time monitoring of embedded SWCNT sensors also allows residence times in the roots, stems and leaves to be estimated, calculated to be 8.3 min (combined residence times of root and stem) and 1.9 min mm−1 leaf, respectively. These results demonstrate the ability of living, wild-type plants to function as chemical monitors of groundwater and communication devices to external electronics at stando distances.