Sensor-based signal amplification and translation (SENSAT) of enzymatic reactions by nanosensors. Credit: Justus T. Metternich et al.
A new form of diagnostic testing signal amplification has been developed by a collaborative team of researchers. Used for enzymatic processes, the sensors developed present new possibilities for improving routine diagnostic procedures.
Diagnostic procedures commonly rely on the use of light to detect concentrations of a particular substance. However, due to the high levels of background noise in the visible light range these methods are limited. To solve this issue, researchers use carbon nanotubes to construct a sensor that fluoresces in the near-infrared range. Additionally, the researchers modified the surface of the sensors to make them sensitive to their chemical environment.
In the study, published in Angewandte Chemie International Edition, researchers discovered that by tailoring the nanotubes to different analytes, an increase in sensitivity is achieved which could significantly increase detection efficiency in diagnostic applications. To demonstrate the efficacy of the sensors, the team utilized p-phenylenediamine and tetramethylbenzidine.
"This enzyme is used in a variety of biochemical detection methods," said Justus Metternich from The Fraunhofer Institute for Microelectronic Circuits and Systems IMS. "In principle, however, the concept can be applied to all kinds of systems. For example, we have also investigated the enzyme β-galactosidase, which is of interest for diagnostic applications. With a few modifications, it could also be used in bioreactions."
The researchers plan to adapt the sensors to several different applications, as well as increasing the stability with quantum defects. "This would be particularly advantageous if you not only want to measure in simple aqueous solutions, but also want to follow enzymatic reactions in complicated environments with cells, in the blood or in a bioreactor itself," said Sebastian Kruss, Professor of Physical Chemistry at Ruhr University Bochum.