Nextgen wearable technology can measure single molecules from a nanolitre of blood in real-time.
A wearable that can monitor the health of a person through the exchange of information via internet without requiring human intervention is the next evolution in this discipline. However, crucial steps in the miniaturisation of biosensors are the conversion of a biological signal into an electrical current as well as the direct sampling of bodily fluids. Now, a study from researchers at the University of Groningen develops a nanopore system which is capable of measuring different metabolites simultaneously in a variety of biological fluids, whilst creating an electrical current, all in a matter of seconds. The team state that incorporation of the nanopore into portable electronic devices will allow developing sensitive, continuous, and non-invasive sensors for metabolites for point-of-care and home diagnostics. The opensource study is published in the journal Nature Communications.
Previous studies show that measuring many metabolites or drugs in the body is complicated and time-consuming, and real-time monitoring is not usually possible. The ionic currents that pass through individual nanopores are emerging as a promising alternative to standard biochemical analysis, with nanopores already integrated into portable devices to determine DNA sequences. However, currently it is not possible to use these nanopores to specifically identify small molecules in complex biological samples. The current study shows that protein sensors in combination with a nanopore acting as an electrical transducer, can accurately quantify metabolites in real-time directly from a nanolitre of blood.
The current study shows that the biological nanopore cytolysin A can be used to monitor the function of two different substrate-binding proteins which are specific to glucose and the amino acid asparagine when they are lodged inside the nanopore. Results show that the nanopores can report the concentration of glucose and asparagine directly from fraction of a drop of blood, sweat, and other bodily fluids in under a minute. Data findings show no sample preparation is required and the concentration of the metabolite can be monitored continuously.
Results show that by adapting the binding proteins to fit inside the nanopore, if a protein binds to its substrate, it changes its conformation which changes the current passing through the nanopore. The lab state that they are using the binding protein as an electrical transducer to detect single molecules of the substrate. They go on to add that the nanopores can be incorporated into a standard device which analyzes the current of hundreds of individual pores simultaneously, whilst operating continuously.
The team surmise they have shown nanopores producing an ionic current, can accurately measure specific molecules in a nanolitre of blood continuously with no sample preparation. For the future, the researchers state they plan to develop a system with proteins which are specific to hundreds of different metabolites.
Source: University of Groningen