A Portable Biosensor for 2,4-Dinitrotoluene Vapors

Abstract

Buried explosive material, e.g., landmines, represent a severe issue for human safety all over the world. Most explosives consist of environmentally hazardous chemicals like 2,4,6-trinitrotoluene (TNT), carcinogenic 2,4-dinitrotoluene (2,4-DNT) and related compounds. Vapors leaking from buried landmines offer a detection marker for landmines, presenting an option to detect landmines without relying on metal detection. 2,4-Dinitrotoluene (DNT), an impurity and byproduct of common TNT synthesis, is a feasible detection marker since it is extremely volatile. We report on the construction of a wireless, handy and cost effective 2,4-dinitrotoluene biosensor combining recombinant bioluminescent bacterial cells and a compact, portable optical detection device. This biosensor could serve as a potential alternative to the current detection technique. The influence of temperature, oxygen and different immobilization procedures on bioluminescence were tested. Oxygen penetration depth in agarose gels was investigated, and showed that aeration with molecular oxygen is necessary to maintain bioluminescence activity at higher cell densities. Bioluminescence was low even at high cell densities and 2,4-DNT concentrations, hence optimization of different prototypes was carried out regarding radiation surface of the gels used for immobilization. These findings were applied to sensor construction, and 50 ppb gaseous 2,4-DNT was successfully detected.

Step detection and energy expenditure at different speeds by three accelerometers in a controlled environment

“…Muscle-strengthening activities should be done twice a week or more. The use of accelerometers enables to objectively assess the subjects’ PA behavior (volume and intensity), but the devices are not equal in their step-detection thresholds, sampling frequency and data processing 5 , 6 . In the USA, less than 10% of the adult population and 24% in Finland were able to meet the recommendations when accelerometers were used to assess PA habituation 7 , 8 .…”

Advancing biological investigations using portable sensors for detection of sensitive samples

“…The vapors leaking from landmines offer an advantage in their detection without relying on the metal used. A cost-effective and wireless biosensor was developed by combining a portable and compact optical device with recombinant bacterial cells for 2, 4-Dinitrotoluene (DNT) detection [ 147 ].…”

Bioluminescence goes portable: recent advances in whole‐cell and cell‐free bioluminescence biosensors

“…(a) Recombinant bioluminescent bacteria cells for sensitive detection of 2,4‐dinitrotoluene implemented into a cost‐effective device for on‐site wireless monitoring (adapted with permission from ref. 56, creative commons (CC) BY license, MDPI). (b) Disposable pad with immobilized bioluminescent bacteria cell exploited for cheap and direct indoor detection of air pollution and toxicity (adapted with permission from ref.…”

“…The combination of recombinant BL bacterial cells with a compact and portable optical detection device has been exploited to design a wireless, low‐weight and cheap portable biosensor for 2,4‐dinitrotoluene (2,4‐DNT) vapours. [ 56 ] This is the first optical 2,4‐DNT biosensor prototype to detect buried landmines and that employs an immobilized recombinant E. coli reporter strain genetically engineered. A photodiode, integrated in a sensor chamber the size of a beverage, connected to a transmitter unit located inside an aluminium case and connected to a computer, was used to measure the production of luciferase induced by 2,4‐DNT.…”