Electrochemical polymerization of aniline in the presence of poly(acrylic acid) and characterization of the resulting films

Leveraging self-signal amplifying poly(acrylic acid)/polyaniline electrodes for label-free electrochemical immunoassays in protein biomarker detection

Accurate quantification of specific biomarkers is essential for clinical diagnosis and evaluating therapeutic efficacy. A self-signal-amplifying poly(acrylic acid) (PAA)/polyaniline (PANI) film-modified disposable and cost-effective screen-printed carbon electrode (SPCE) has been developed for constructing new label-free immunosensors targeting two model biomarkers: human immunoglobulin G (IgG) and alpha-fetoprotein (AFP). The electrochemically deposited PAA/PANI film on the SPCE serves a dual function: both a bio-immobilization support and a signal amplifier, enhancing biomarker detection sensitivity and efficiency. The self-signal amplification properties of PANI streamline the detection process. At the same time, the high-density surface carboxyl groups from embedded PAA enable covalent conjugation with capture antibodies (anti-IgG and anti-AFP). Subsequently, antibody-immobilized PAA/PANI film-modified SPCEs, as immunosensors, successfully detect IgG and AFP without the need for external redox probes. The reductions in the electrochemical PANI signals of the immunosensors are linearly proportional to the logarithm of IgG and AFP concentrations. The proposed immunosensors exhibit sufficiently wide ranges of calibration curves from 0.10 to 50 ng mL-1, with limits of detection of 0.080 ng mL-1 for IgG and 0.090 ng mL-1 for AFP. The sensors exhibit satisfactory sensitivity and selectivity, indicating their potential for accurate and reliable detection.

Ramamurthy P. Development of Molecularly Imprinted Conducting Polymer Composite Film-Based Electrochemical Sensor for Melamine Detection in Infant Formula

Simple, fast, and sensitive molecularly imprinted composite thin-film-based electrochemical sensor developed by using in situ co-electropolymerization of aniline and acrylic acid in the presence of melamine as a template is described here. The prepolymerization complex formation was studied by using Fourier transform infrared (FTIR) spectrophotometry, while the film formation was performed and characterized by cyclic voltammetry, Fourier transform infrared (FTIR), and scanning electron microscopy (SEM). The optimization of important parameters and removal of melamine generated the binding sites in the polymer matrix, which can recognize melamine specifically. Electrochemical measurements were performed to achieve the linear range, the limit of quantification, and limit of detection of 0.1-180, 0.0573, and 0.0172 nM, respectively. The sensitivity of the sensor was attributed to the synergistic effects of amine from aniline and the carboxylic group from acrylic acid to form multiple noncovalent interactions with the template. Melamine-spiked infant formula and raw milk were analyzed by the developed sensor, and the recovery range of 95.87-105.63% with a relative standard deviation of 1.11-2.23% was obtained. The results showed that the developed sensor using the new composite polymer receptor is promising for the online monitoring of melamine in the food industries in the future.

Self-assembled multimicellar vesicles via complexation of a rigid conjugated polymer with an amphiphilic block copolymer

We report here a facile method for fabrication of multimicellar vesicles from self-assembled complexes of a flexible coil-like block copolymer and a rigid rod conjugated homopolymer.