Biosensor-universal
Conductive hydrogel allows you to form good biosensors
sci-lib based on nanotechweb materials: Conducting hydrogel makes a good biosensorA joint team of researchers from the United States and China has developed a new flexible biosensor that allows recording a wide range of human metabolites, including glucose, uric acid and cholesterol.
The device is made of nanostructured polymer hydrogels. At the same time, it is very sensitive – it allows you to detect metabolites in one drop of blood.
Most of the biosensors created earlier contain a number of electronic materials that allow detecting only one type of metabolite. Practically none of the materials used for the formation of electrodes makes it possible to expand the use of devices to several metabolites. In contrast, the device developed by a joint team of researchers from the University of Texas (USA) and Nanjing University (China) contains a conductive polymer hydrogel that allows detecting a whole spectrum of molecules. Thus, the published work is the first step in the direction of manufacturing simple and inexpensive chip-integrated sensor arrays using only one material as electrodes.
Hydrogels are three-dimensional polymer networks that can hold large amounts of water without dissolving and have a structure much like biological tissues. It is worth noting that these substances are quite easy to handle and process, so scientists often consider them as the basis for their developments.
The new device proposed by the joint research group uses a conductive polymer hydrogel containing platinum nanoparticles as an electrode. To obtain a workable sample, scientists sequentially deposited hydrogel precursors, platinum nanoparticles and specific enzymes on a glass-carbon electrode, which made it possible to form a hybrid bioelectrode (platinum nanoparticles in this case are used to catalyze the formation of hydrogen peroxide in an enzymatic reaction; the enzymes themselves are needed to increase the current, i.e. amplify the signal generated by the device).
The system, consisting of hydrogel, platinum nanoparticles and enzymes, works very well and allows detecting various metabolites in concentrations present in human blood. For example, the biosensor can detect uric acid with a concentration in the range of 0.07 – 1 mM, cholesterol with a concentration of 0.3 – 9 mM, triglycerides with a concentration of 0.2 – 5 mM. In this case, the result can be obtained within three seconds.
Diagram from the article in Nano Letters – VM.
The ability to quickly and easily identify these metabolites is extremely important for monitoring the health of patients in clinical diagnostics. At the moment, the biosensor allows you to identify molecules "responsible" for diabetes mellitus, gout and diseases of the cardiovascular system. The next stage of the work, as scientists say, will be the expansion of the spectrum of metabolites that the device allows to detect.
In the future, the scheme proposed by scientists for connecting polymer hydrogels with enzymes to produce biosensors on a chip can be scaled up for commercial production, since it has a fairly low cost. The team of researchers also notes that they are already trying to create biosensors that will connect to portable terminals using a wireless connection.
Detailed results of the work are published in the journal Nano Letters (Li et al., A Nanostructured Conductive Hydrogels-Based Biosensor Platform for Human Metabolite Detection – VM).
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