Electropolymerized Receptor Coatings for the Quantitative Detection of Histamine with a Catheter-Based, Diagnostic Sensor

Abstract

In this article, we report on the development of a catheter-based, biomimetic sensor as a step toward a minimally invasive diagnostic instrument in the context of functional bowel disorders. Histamine is a key mediator in allergic and inflammatory processes in the small intestines; however, it is a challenge to determine histamine levels at the duodenal mucosa, and classical bioreceptors are unsuitable for use in the digestive medium of bowel fluid. Therefore, we have developed molecularly imprinted polypyrrole coatings for impedimetric sensing electrodes, which enable the quantification of histamine in nondiluted, human bowel fluid in a broad concentration range from 25 nM to 1 μM. The electrodes show negligible cross-sensitivity to histidine as a competitor molecule and, for comparison, we also evaluated the response of nonimprinted and taurine-imprinted polypyrrole to histamine. Furthermore, using equivalent-circuit modeling, we found that the molecular recognition of histamine by polypyrrole primarily increases the resistive component of the electrode−liquid interface while capacitive effects are negligible. The sensor, integrated into a catheter, measures differentially to correct for nonspecific adsorption effects in the complex matrix of bowel fluids, and a single triggering frequency is sufficient to determine histamine concentrations. Together, these features are beneficial for real-time diagnostic tests.

A Review on Bio- and Chemosensors for the Detection of Biogenic Amines in Food Safety Applications: The Status in 2022

“…In a recent work, histamine MIPs were developed based on electro-polymerization of pyrrole to polypyrrole, a conjugated, electrically conducting polymer shown in Figure 9 b. The host–guest interaction relies primarily on π–π stacking, which is widely insensitive to pH, except for strong acids and bases [ 197 ]. Electro-polymerization can be applied to numerous monomers and blends thereof [ 198 ], allowing for a comparatively facile synthesis directly at the surface of metallic electrodes, which will be discussed in the following subsection.…”

“…While this illustrates the selectivity of molecular recognition, one may assume that the response of the MIP coating is to a small part also caused by nonselective adsorption of target molecules. In very recent publications (see Section 4.4 and, e.g., [ 197 ]), authors have employed a differential signal between the active channel (MIP) and the passive channel (NIP) to determine the signal change truly through molecular recognition. As shown in Figure 10 b, the cross-selectivity to competitor molecules is four to five times lower as compared to selective recognition [ 203 ].…”

“…Based on work by Ratautaite et al in ref. [ 204 ], Wackers and coworkers designed a sensing probe that is small enough to fit into a nasogastric catheter, as shown in Figure 11 a [ 197 ]. The electrodes consist of titanium pins that are coated with electropolymerized polypyrrole; two pins were coated with histamine-imprinted PPy, and the two other pins had a NIP layer to allow for differential sensing in complex fluids.…”

Thermal Pyocyanin Sensor Based on Molecularly Imprinted Polymers for the Indirect Detection of Pseudomonas aeruginosa

“…The reagents used for MIP synthesis are carefully chosen, often aimed at maximizing noncovalent interaction between the functional groups of the template and the components of the polymeric matrix. − The template species can then be removed by mechanical grinding and solvent-based extraction methods such as Soxhlet extraction, leaving vacant binding sites in the polymeric matrix . The procedures used to synthesize MIPs are numerous (precipitation, emulsion, solid-phase synthesis, and electropolymerization), − though monolithic bulk free-radical polymerization remains the most straightforward approach . In addition to their low-cost and scalable production process, MIPs also offer a robust alternative to biological receptors that often require physiological conditions to operate optimally and have limited shelf-life.…”

Detection of yeast strains by combining surface-imprinted polymers with impedance-based readout

“…By using the two circuits, Bode plots were created containing the data for the last five minutes of the PBS baseline and the equilibrium after injection of yeast and washing. The different parameters were obtained by using in-house developed software based on the derivative-free simplex search method of Lagarias et al as described by Wackers et al[52]. In both cases, the data was plotted for the real and the imaginary part of the impedance.…”