Self-assembly Synthesis of Molecularly Imprinted Polymers for the Ultrasensitive Electrochemical Determination of Testosterone.

Molecularly imprinted polymers (MIPs) can often bind target molecules with high selectivity and specificity. When used as MIPs, conductive polymers may have unique binding capabilities; they often contain aromatic rings and functional groups, which can undergo π－π and hydrogen bonding interactions with similarly structured target (or template) molecules. In this work, an electrochemical method was used to optimize the synthetic self-assembly of poly(aniline-co-metanilic acid) and testosterone, forming testosterone-imprinted electronically conductive polymers (TIECPs) on sensing electrodes. The linear sensing range for testosterone was from 0.1 to 100 pg/mL, and the limit of detection was as low as ~pM. Random urine samples were collected and diluted 1000-fold to measure testosterone concentration using the above TIECP sensors; results were compared with a commercial ARCHITECT ci 8200 system. The testosterone concentrations in the tested samples were in the range of 0.33 ± 0.09 to 9.13 ± 1.33 ng/mL. The mean accuracy of the TIECP-coated sensors was 90.3 ± 7.0%.

Electrochemical sensing of urinary progesterone with molecularly imprinted poly(aniline-co-metanilic acid)s.

In this work, progesterone is imprinted into poly(aniline-co-metanilic acid) on the working electrode of an electrochemical sensing chip. This sensing chip was used directly to optimize the composition of the imprinting polymer. Poly(aniline-co-metanilic acid) deposited from a 1 : 3 molar ratio of aniline (ANI) : m-aminobenzenesulfonic acid (MSAN) had an imprinting effectiveness which led to a four-fold greater electrochemical response than pure polyaniline. The electrochemical sensing of progesterone had a limit of detection (LOD) less than 1.0 pg mL-1, and the direct electrochemical response was very weak even at high interference concentrations. Results from potential interferents (urea, testosterone, creatinine and 17-ß estradiol) are reported. The progesterone levels that were measured in a random urine analysis were compared with those obtained using a commercial ARCHITECT system, and the accuracy of the progesterone concentration was 89.0 ± 5.3% at a concentration of 0.64-5.27 ng mL-1.