A Disposable Saliva Electrochemical MIP-Based Biosensor for Detection of the Stress Biomarker α-Amylase in Point-of-Care Applications

Abstract

The design and synthesis of artificial receptors based on molecular imprinting (MI) technology for the development of a new MIP-based biosensor for detection of the stress biomarker α-amylase in human saliva in point-of-care (PoC) applications is described in this work. The portable electrochemical devices for monitoring α-amylase consists of cost-effective and disposable gold screen-printed electrodes (AuSPEs). To build the electrochemical device, the template biomolecule was firstly immobilized directly over the working area of the gold chip previously activated with a self-assembled monolayer (SAM) of cysteamine (CA). Then, pyrrole (Py) monomer was selected as building block of a polymeric network prepared by CV electropolymerization. After the electropolymerization process, the enzyme was removed from the polymer film in order to build the specific recognition sites for the target enzyme. The MIP biosensor showed a very wide linear concentration range (between 3.0 × 10−4 to 0.60 mg mL−1 in buffer solution and between 3.0 × 10−4 to 3.0 × 10−2 mg mL−1 in human saliva) and low detection levels were achieved (LOD < 3.0 × 10−4 mg mL−1) using square wave voltammetry (SWV) as the electroanalytical technique.

Advances in Electrochemical Biosensors Based on Nanomaterials for Protein Biomarker Detection in Saliva

“…The clinical value of saliva‐based protein sensors is extended to other infectious disease diagnostics (i.e., rapid tests for malaria), [ 9 ] personalized medicine (i.e., routine tests for chronic lung disease or heart disease), [ 10,11 ] and other medical conditions affecting millions of people (i.e., on‐site tests for physiological stress detection, early‐stage detection of cancer, etc.). [ 12–14 ]…”

“…MIPs use the target proteins as templates for synthesizing rigid tridimensional (3D) polymer structures around the binding sites of the protein. [ 14 ] Following the extraction of the template, the target protein is detected by rebinding to the MIP containing empty binding sites. MIPs may comprise conducting polymer structures and may form electroactive films on the top of the electrodes for the transduction of the signal.…”

Electrochemical sensors for analyte in saliva: recent update

“…Enzymes, cytokines and growth factors have been reported for analysis. For instance, electrochemical immunosensors have been developed for the detection of salivary alpha-amylase, a digestive enzyme whose levels can serve as a marker of stress and sympathetic nervous system activity (Garcia et al , 2018; Martins et al , 2021b; Rebelo et al , 2021; Zhang et al , 2014). These sensors typically use specific antibodies immobilized onto modified electrode surfaces, which selectively bind to alpha-amylase and generate a measurable electrochemical signal.…”

Molecularly Imprinted Polymer Biosensor Based on Nitrogen-Doped Electrochemically Exfoliated Graphene/Ti3 CNTX MXene Nanocomposite for Metabolites Detection

“…This deficiency can result in incomplete removal of template molecules, slow binding kinetics, and reduced sensitivity of MIP biosensors. − To address these challenges, the electropolymerization of conductive monomers, such as pyrrole, , aniline, and thiophene, offers a direct, in situ fabrication of MIPs on the electrode’s surface. This method yields electrically conductive polymeric films with controllable thickness and reproducible outcomes, thereby enhancing the precision of MIP biosensors. , Furthermore, incorporating cross-linkers such as boronic acid-derived compounds during the electropolymerization process confers superior affinity toward target templates, contributes to increased mechanical and chemical stability, and improves the efficiency of created cavities for entrapping templates …”