Biosensors boost from new organic semiconducting material

An international team has developed a new organic semiconducting material that is claimed to outperform current options for the next generation of biosensors. 

biosensors
Several critical challenges were overcome to develop the new type of polymer that has great potential for next-generation biosensors (© 2021 KAUST; Xavier Pita)

According to researcher leaders KAUST, research effort is being put into novel types of biosensors that interact directly with the body to detect key biochemicals and serve as indicators of health and disease.

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“For a sensor to be compatible with the body, we need to use soft organic materials with mechanical properties that match those of biological tissues,” said Rawad Hallani, a former research scientist in the KAUST team, who developed the polymer along with researchers at universities in the UK and US.

According to Hallani, the polymer is designed for use in organic electrochemical transistors (OECTs). For these types of devices, the polymer should allow specific ions and biochemical compounds to permeate into the polymer and dope it, which can modulate its electrochemical semiconducting properties. “The fluctuation in the electrochemical properties is what we are actually measuring as an output signal of the OECT,” he said in a statement.

The team’s innovation is said to be based on polymers (polythiophenes) with chemical groups (glycols) attached in precisely controlled positions. According to KAUST, controlling the locations of the glycol groups in ways not previously achieved was a key aspect of the breakthrough.

“Identifying the right polymer design to fit all the criteria that you are looking for is the tough part,” said Hallani. “Sometimes what can optimise the performance of the material can negatively affect its stability, so we need to keep in mind the energetic as well as the electronic properties of the polymer.”

The team used computational chemistry modelling to help achieve the right design, and they were further aided by specialised x-ray scattering analysis and scanning tunnelling electron microscopy to monitor the structure of their polymers. These techniques revealed how the location of the glycol groups affected the material’s microstructure and electronic properties.

“We are excited by the progress Rawad made on the polymer synthesis, and we are now looking forward to testing our new polymer in specific biosensor devices.” said Iain McCulloch of the KAUST team, who is attached to Oxford University.

McCulloch said the research group is now trying to improve the stability of their polymers and the sensors built from them, as they move from laboratory demonstrations toward real world applications.

The team’s findings have been published in the Journal of the American Chemical Society.