Effects of Poison Detected by Fast Lab-On-A-Chip


By mimicking human metabolism, a new ‘lab on a chip’ system, developed by the University of Twente in The Netherlands, can analyze the effects of toxic substances on hemoglobin fast. Floris van den Brink, a scientist at Twente made the breakthrough by developing a fast and efficient mixer for this purpose.

The effects of medication or toxic substances foreign to the human body are difficult to examine as they often have a very short lifetime. This makes it virtually impossible to determine the exact effects before the damage is done. Polycyclic aromatic hydrocarbons (PAH) are released at asphalt road works or coal power plants. The effect of PAH interacting with hemoglobin in blood can now be examined using van den Brink’s new lab on a chip system.

One of the liver’s functions is to convert these foreign substances into metabolites. The chip mimics this by producing PAH metabolites like hydroxypyrene with a tiny electrochemical reactor. The metabolites are then mixed with hemoglobin to determine how the toxic and highly reactive metabolite binds to hemoglobin. By using a new mixing technique, this process has been sped up and can be done well within a second.

Possible remedies for detoxing the blood can also be examined by using the same micro laboratory. Used in this way, the chip can measure the effects of medication without having to use laboratory animals.

The whole reactor and mixing unit on a chip. (Image credit: University of Twente)

The mixing of fluids on a nano or even a micro scale is tricky. Mechanical stirring is not an option and the fluids behave differently in miniscule fluid channels. Van den Brink’s design consists of two circular mixing chambers, each composed of of tiny channels that run at a gradient. The first substance to be mixed enters the chamber at the top, while the other is inserted from the bottom. Mixing can be accelerated significantly by using the difference in gradient angles.

The entire mixer is small and only measures approximately 0.1 square millimeter. The output is analyzed by using mass spectrometry. The yield of the reactor is improved by using diamond electrodes instead of the normal platinum ones.

The system can be used for analyzing numerous types of interactions with proteins, with measuring the effect of hydroxypyrene metabolites on hemoglobin being only one example. It might even be possible to use the system to analyze DNA. The chip is a fast and powerful tool, especially given that proteomics is fast gaining importance in the development of medicine.

Full study has been published in the journal Lab Chip.