A team of scientists in the United States has developed a wearable fingertip sensor to enable crime scene investigators to rapidly detect explosives and gunshot residue.
Traditional forensic analysis is typically carried out in a central laboratory, which requires time-consuming processes such as sampling, transportation and storage. The researchers have developed this wearable sensor to move forensic analysis from out of the lab to directly at the scene of the crime.
The sensor is made up of two components: an electrode screen-printed onto a stretchable cot worn on the index finger and a second cot, worn on the thumb, coated with a solid-state ionogel electrolyte. To sample a surface, the investigator simply swipes with the index finger and then presses the finger and thumb together to complete an electrochemical cell. The resulting voltammetric signal is read by a field-portable electrochemical analyser that shows distinct peaks for gunshot residue and trace explosives. The entire process can be carried out independently within four minutes.