Biosensors measure the concentration of molecules in biological samples for medical, environmental and industrial applications. Ideally, they should provide continuous data in real time. However, continuous monitoring of small molecules at low concentrations is problematic. Researchers at the Technical University of Eindhoven have developed an innovative approach to the problem using molecular doubles. This may prove to be crucial in future biosensors for health monitoring and early disease detection. The results are published in the ACS Sensors journal.
Researchers from the departments of biomedical engineering and applied physics at the Technical University of Eindhoven have come up with a new approach to detecting molecules of interest with small masses. It is these molecules that are used to monitor the overall physical condition of a person.
Junhong Yang, Menno Prince and his colleagues demonstrate a new approach that can continuously measure the concentration of low-mass molecules of interest in samples based on biosensing by particle mobility (BPM).
Existing biosensors usually provide one measurement result for one biological sample. A sample may consist of blood, sweat, urine or saliva and the result may be protein, hormone, drug or virus levels in the sample.
However, it would be better if the sensors gave a continuous flow of data, which would allow the person to monitor how the disease develops over time.
Each biosensor consists of three main parts:
- molecular component with a bioreceptor that can bind to the molecule of interest;
- is a conversion principle that converts molecular recognition into a detectable signal;
- a detection system that records a signal and provides a response in the form of a numeric, graphic, sound or light indication that is easy for the user to interpret.
“In this work, we focused on the first part, the development of a molecular principle for continuous measurement of molecules of interest with low molecular weight and low concentration,” explains one of the authors of the development.
The sensor, developed by Jan, Prince and the team, adapted the use of molecular doubles or fake versions of molecules of interest.
How do these similar molecules help to detect real molecules? The surface of the sensor is covered with antibodies that can bind to the molecules of interest. When there are no molecules in the test fluid, similar molecules can bind freely to the antibodies. However, when the molecules of interest are found, they can bind to antibodies. As a result, the doppelgangers are freed from “work”.
The work of the sensory platform is quite simple and, I must say, ingenious. All molecular binding events must be reversible. This includes binding between antibodies and twins, as well as binding between antibodies and molecules of interest in the solution.
There are repeated binding and decoupling events involving similar molecules or molecules of interest in a fluid and these events can be easily measured by optical microscopy by recording the state of the microparticle.