Portable, low-cost and quantitative detection of a broad range of targets at home and in the field has the potential to revolutionize medical diagnostics and environmental monitoring. Despite many years of research, very few such devices are commercially available. Taking advantage of the wide availability and low cost of the pocket-sized personal glucose meter, Cocaine and Uranium can be tested using DNA/RNA biosensors such as Cocaine aptamer-based sensor, Interferon-gamma aptamer-based sensor, Adenosine aptamer-based sensor, Uranium DNAzyme-based sensor for detection in serum and blood.

Glucose Meter Can Detect Cocaine and Uranium in Blood

Researchers used an unmodified Accu-Chek Aviva Glucose Monitor to measure a variety of substances including CoCaine and Uranium.

Personal glucose meters and functional DNA sensors can be used to quantify a variety of analytical targets. Researchers propose the use of functional DNA-conjugated invertase to link glucose detection to the detection of other targets, and use the concentration of glucose to quantify the other targets of interest present in the samples.

Functional DNAs include DNAzymes (also called deoxyribozymes, catalytic DNAs or DNA enzymes), which act as catalysts, aptamers (which selectively bind targets) and aptazymes (which are a combination of the two). They are members of the functional nucleic acid family, which also includes RNA-based ribozymes, aptamers and aptazymes. The functional nucleic acids are selected from libraries of DNA or RNA with up to 1 × 1015 random sequences by means of a process known as in vitro selection or the systematic evolution of ligands by exponential enrichment (SELEX). The targets of functional DNA/RNAs can range from metal ions and small organic molecules to biomolecules, and even viruses or cells, making functional DNA/RNA a general platform for recognizing a broad range of targets.

Researchers Yu Xiang and Yi Lu demonstrated a method to use such low-cost glucose meters to quantify non-glucose targets, ranging from a recreational drug (cocaine, 3.4 mM detection limit) to an important biological cofactor (adenosine, 18 mM detection limit), to a disease marker (interferon-gamma of tuberculosis, 2.6 nM detection limit) and a toxic metal ion (uranium, 9.1 nM detection limit). The method is based on the target-induced release of invertase from a functional-DNA–invertase conjugate. The released invertase converts sucrose into glucose, which is detectable using the meter. The approach should be easily applicable to the detection of many other targets through the use of suitable functional-DNA partners (aptamers, DNAzymes or aptazymes).

Many functional DNA/RNA sensors have been developed for a broad range of targets, and use laboratory-based devices to generate signal outputs including fluorescence, colorimetry, electrochemistry and magnetic resonance. Colorimetric sensors, including dipstick tests, have been developed for qualitative or semi-quantitative detection that requires no instrumentation, similar to the ubiquitous enzyme-linked immunosorbent assay (ELISA) method widely used in diagnostics. However, numerous targets of interest require quantitative information, and laboratory-based devices are usually needed to provide this information. PGMs would be ideal alternatives to laboratory-based devices in detecting and quantifying these targets at home and in the field, but a link between glucose concentration and other target concentrations must be established before PGMs can be used.