Abstract
Synthetic
cathinones (also known as bath salts) are designer drugs sharing a similar core
structure with amphetamines and 3, 4-methylenedioxy-methamphetamine (MDMA). They
are highly addictive central nervous system stimulants, and are associated with
many negative health consequences, including even death. Although these drugs
have emerged only recently, abuse of bath salts has become a threat to public
health and safety due to their severe toxicity, increasingly broad
availability, and difficulty of regulation. More importantly, there is
currently no reliable presumptive test for any synthetic cathinone. Chemical
spot tests used to detect conventional drugs such as cocaine, methamphetamine, and
opioids show no cross-reactivity to synthetic cathinones. FIU inventors have developed
cross-reactive aptamers with structure-switching functionality and sensors for
the detection of synthetic cathinones. The generation of a structure-switching
cross-reactive aptamer entails digesting the cross-reactive aptamer with an
exonuclease mixture, such as exonuclease III (Exo Ill) and exonuclease I (Exo
I). The resulting digestion product has structure-switching functionality with
similar or equal affinity as its parent cross-reactive aptamer and can be
directly employed in folding-based aptamer sensors. The structure-switching
cross-reactive aptamers have been used in two different type of assays. One is
a label free dye displacement assay where the presence of synthetic cathinones
is reported via a sensitive colorimetric signal for naked-eye detection. This colorimetric
assay has excellent specificity because the aptamer does not cross-react to
non-synthetic cathinone interferents, can detect nanomolar synthetic cathinone
concentrations even in urine and saliva in a label-free manner via instrumental
means, and can also achieve instantaneous detection of as low as 6.3 μM with
the naked-eye when the dye is used at a micromolar concentration. The second assay
consist of incorporating the structure-switching cross-reactive aptamers into
an electrochemical aptamer-based (E-AB) sensor, which comprises an electrode, and
the detection of the synthetic cathinone(s) is done by measuring an increase in
current generated upon binding of the synthetic cathinone(s) to the sensor. E-AB
sensors are an ideal choice for the detection of seized substances, because
they are insensitive to sample matrix effects, have rapid response times
(seconds-scale), can perform detection with minimal sample preparation
requirements, and can be easily miniaturized to detect low-volume samples
(micro liters), thus allowing for analysis of trace amounts of substances.
Benefit
1. Colorimetric detection:Compatible for both clinical and field settingsColor change from colorless to bright blue within minutesCan be performed in a single tubeHas detection limit suitable for screening in biosamples2. Electrochemical detection:High sensitivity and specificityRead-out can be quantified in secondsInsensitive to sample matrix effectsMinimal sample preparation requirements
Market Application
Drug testing in clinical and field settings
Brochure
