Rapid on-site drug detection using wearable sensor

The drugs can be detected by using nanomaterials technology that amplify the optical signal of narcotics to a flexible, body-worn material.

The technology enables fast and highly sensitive drug detection -- the sweat patch is attached to the skin for a certain period of time and then irradiated with light for testing.

According to the researchers, it only takes one minute without requiring additional process.

"The developed technology would overcome the technological limitations on identifying drug and prohibited substance use and enable drug detection without invasive and ethical problem," said researcher Ho Sang Jung from the Korea Institute of Materials Science (KIMS).

For the study, published in the journal ACS Applied Materials and Interfaces, the researchers focused on sweat which is not invasive and relatively free from human rights issues.

However, only small amount of substances is discharged in sweat, even though sweat contains various drugs taken so a highly sensitive sensor technology had to be developed for better detection.

The team's highly sensitive sensing utilized the surface-enhanced Raman scattering technology capable of enhancing the Raman signal of chemical substances by 1010 times and more.

As the Raman scattering signal includes the specific signal of molecules, intuitive substance identification is possible no matter what drug is discharged.

The researchers paid attention to the cocoon protein, a flexible and wearable material to develop a wearable optical sensor, according to the researchers.

A silk fibroin solution, a natural protein, was extracted from silkworm cocoon to make a 160 nanometer (nm) thick film.

The film was coated with 250 nm thick silver nanowire and transferred to the medical patch that can be attached to the skin.

Once the patch absorbs the sweat, the drug substance in the sweat penetrates the wearable sensor and reaches the silver nanowire.

By exposing the Raman laser on the patch, the drug can be detected in real time without removing the sensor.