Electropolymerised Polypyrroles as Active Layers for Molecularly Imprinted Sensors: Fabrication and Applications

Abstract

Conjugated polymers are widely used in the development of sensors, but even though they are sensitive and robust, they typically show limited selectivity, being cross-sensitive to many substances. In turn, molecular imprinting is a method involving modification of the microstructure of the surface to incorporate cavities, whose shape matches that of the “template”—the analyte to be detected, resulting in high selectivity. The primary goal of this review is to report on and briefly explain the most relevant recent developments related to sensors utilising molecularly imprinted polypyrrole layers and their applications, particularly regarding the detection of bioactive substances. The key approaches to depositing such layers and the most relevant types of analytes are highlighted, and the various trends in the development of this type of sensors are explored.

Application of Polypyrrole-Based Electrochemical Biosensor for the Early Diagnosis of Colorectal Cancer

“…Moreover, the electrochemical properties of PPy, such as the conductivity, morphology, thickness, structure, and porosity, can also be modulated by controlling the type and concentration of dopants, electrolytes, and solvent, as well as the pH value, temperature, and monomer concentration of the bulk solution [ 54 , 73 , 74 ]. In addition to normal PPy preparation, electropolymerization can be utilized for the synthesis of molecularly imprinted polymer (MIP) films on the electrode surface with high stability and low cost [ 72 , 75 , 76 ]. During the preparation of the MIP, additional electrochemical operations can be performed for overoxidation after the formation of the initial electrodeposited PPy layer [ 77 , 78 ].…”

“…It is a kind of polymer with specific recognition sites that are created artificially and complement the imprinted analyte, and it is also known as a “bionic receptor” [ 117 ]. Considering its biocompatibility, excellent electron transmission rate, and good environmental stability [ 108 , 110 ], molecularly imprinted polypyrrole (MIPPy) can be polymerized and impressed simultaneously using amperometric, potentiometric, or potential scanning methods or polymerized on a template-modified electrode [ 75 ]. It can be used for biomedical and environmental monitoring applications, and it is cost-effective and exhibits excellent selectivity, sensitivity, and chemical/thermal stability [ 75 , 111 ].…”

“…Considering its biocompatibility, excellent electron transmission rate, and good environmental stability [ 108 , 110 ], molecularly imprinted polypyrrole (MIPPy) can be polymerized and impressed simultaneously using amperometric, potentiometric, or potential scanning methods or polymerized on a template-modified electrode [ 75 ]. It can be used for biomedical and environmental monitoring applications, and it is cost-effective and exhibits excellent selectivity, sensitivity, and chemical/thermal stability [ 75 , 111 ]. Ding et al described an electrochemical method that can be used to detect glyphosate with a detection limit of 1.94 ng/mL based on the construction of molecularly imprinted polypyrrole nanotubes (MIPNs) that exhibited excellent conductivity and specificity ( Figure 5 B) [ 108 ].…”

Stretchable and Highly Sensitive Flexible Strain Sensor Based on a Three‐Layer Core–Shell Structure of Polydopamine/Polypyrrole@Natural Rubber for Human Activity Monitoring

“…PPy, when combined with substrates, could be created conducting composites that can be utilized as flexible sensors. [47,48] However, in most cases, the application of PPy remains challenging due to its poor binding with matrix polymer, which may reduce the performance and conductivity of the sensor. [49] As a kind of skin-friendly polymer elastomer with excellent elasticity, NR is selected as the substrate for the strain sensor.…”

The Role of Electrochemical and Spectroelectrochemical Techniques in the Preparation and Characterization of Conjugated Polymers: From Polyaniline to Modern Organic Semiconductors

“…Significant achievements included, in particular, the study of the mechanisms of polyaniline formation and the doping mechanisms of many polymers. Years of research have led to many organic semiconductors being tested in applications such as organic light-emitting diodes (OLEDs) [ 7 , 8 ] sensors [ 9 , 10 , 11 ] and solar cells. Electrochemical and spectroelectrochemical techniques used for investigating the properties of conjugated polymers are briefly presented in the manuscript.…”