Electrochemical studies of lateral flow assay test results for procalcitonin detection

Abstract

In this study, the lateral flow assay (LFA) has been developed for the detection of bacterial infection (BI) by specific biomarker procalcitonin (PCT), without a need for complicated instrumentations and technical expertise. For the development of the assay, gold nanoparticles (AuNP) and their conjugates with antibodies specific to the model antigen PCT are assessed. Polyclonal antibody (pAb) labelled with gold nanoparticles (AuNP) to obtain the AuNP-pAb complex and the specific monoclonal antibody (mAb) have been dropped at the test zone. This complex is placed over the conjugate line of the LFA strip. In the absence of PCT or the presence of other biomarkers, the test line remained colourless, which revealed the specificity of assay towards PCT among a pool of various analytes. Herein, observations have been made through two different platforms for quantitative and qualitative analysis for the detection of PCT biomarker. The qualitative analysis has been performed on the basis of appearance red color in the test band, while for quantitative analysis, a novel approach has been adopted. Herein, the nitrocellulose membrane (paper strip) is cut out from the LFA strip and used for electrochemical studies under similar solution conditions. Different paper strips presented different cyclic voltammograms (CV) that could be correlated to varying PCT concentrations captured at the test line of the paper strip. The qualitative detection limit for PCT using this LFA was determined to be 2 ng/ml and the quantitative detection limit was 1 ng/ml. The electrochemical response studies of the paper strip by CV technique revealed the sensitivity value of 0.695 mA ng/ml.

Electrochemical Investigation of Viral Respiratory Infection Inflammatory Biomarker Serum Amyloid A Protein by Using PtNP Modified Electrode

“…The obtained calibration plot (Figure 5b) indicated linear relationship between peak currents values in each recorded DPV and SAA concentration. [28] The linearity equation ( 1) is as follows:…”

Reduced Graphene Oxide‐Gold Nanoparticle Nanohybrid Modified Cost‐Effective Paper‐Based Biosensor for Procalcitonin Detection

“…In brief, 25 ml of a 2.5 mM Tetra chloroauric (III) acid aqueous solution was prepared and heated to approximately 60 °C before being mixed dropwise with 1 ml of a 5 % aqueous solution of tri-sodium citrate dihydrate (TSC; 1 ml). [46][47][48][49] The solution was stirred continuously for 35 minutes resulting in a color change from pale yellow/ colorless to purple and finally to ruby red.…”

“…[10,11] Electrochemical biosensors can be used in a large visual range where electrochemical signals are scaled and converted directly to the significant PCT concentration. [12][13][14][15][16] Conductive paper has recently been explored to fabricate sensor-strip as it may serve the increasing demand for low-cost point-of-care sensors. [17,18] Furthermore, conductive paper can aid in the immobilization of sensitive materials on the surface and strengthen the substrate surface's efficiency and sustainability due to the highly strong and stable bonding between surface and material.…”

“…In this context, an electrochemical biosensor can be a suitable alternative for the specific detection of PCT biomarkers [10,11] . Electrochemical biosensors can be used in a large visual range where electrochemical signals are scaled and converted directly to the significant PCT concentration [12–16] …”

Development of conducting paper-based electrochemical biosensor for procalcitonin detection

“…In addition, solvent treatment of PEDOT:PSS can promote rapid electron transfer between the paper surface and the solution, thereby increasing conductivity. Conductive polymers, when integrated with gold nanoparticles (AuNP), silver, and other metals and their oxide nanoparticles, etc., can improve electrochemical, optical, and physical properties [23][24][25]. Various studies have used nanoparticles with PEDOT:PSS to improve surface properties and electrical conductivity [26][27][28].…”