Electrochemical biosensing has been extensively explored as a solution to cardiac troponin I (cTnI) detection. Biosensing has evolved to include signal amplification strategies such as nanoparticle-functionalised electrodes and using conductive coatings to enhance detection limits. However, these methods often introduce challenges, including signal noise, increased complexity requiring bulky equipment, intricate fabrication processes, and reduced assay reproducibility, limiting their clinical applicability. Three-dimensional printing allows for rapid and customisable electrode production, making it an ideal candidate for innovative electrode design which meets specific user needs and minimises variability in carbon electrode manufacturing. This study details various small electrodes fabricated using fused filament fabrication 3D printing [1], integrating multiwall carbon nanotubes and polylactic acid (MWCNT/PLA) as a simpler, more robust alternative. The 3D-printed electrodes were tailored for the electrochemical detection of oxidised tetramethylbenzidine (TMB_ox) using an electrochemical enzyme-linked immunosorbent assay (ELISA) for cTnI detection as formulated by previous work [2]. Electrodes of varying sizes and composite materials were fabricated and evaluated to optimise performance for TMB_ox detection. A sandwich ELISA format was used to capture and label cTnI, allowing for the indirect quantification of cTnI via chronoamperometric measurements, with absorbance-based ELISA as a comparator. This presentation will discuss how the miniaturisation and material optimisation of 3D-printed electrodes improve electrochemical ELISA sensitivity and reliability, and the prospects of integrating these technologies into a portable electrochemical ELISA format.

1. Xue, Z.; Patel, K.; Bhatia, P.; Miller, C.L.; Shergill, R.S.; Patel, B.A. 3D-Printed Microelectrodes for Biological Measurement. Anal. Chem. 2024, 96, 12701–12709, doi:10.1021/acs.analchem.4c01585.
2. Docherty, N.; Collins, L.; Pang, S.; Fu, Y.; Milne, S.; Corrigan, D. Cost-Effective Amperometric Immunosensor for Cardiac Troponin I as a Step towards Affordable Point-of-Care Diagnosis of Acute Myocardial Infarction. Sensing and Bio-Sensing Research 2025, 47, 100725, doi:10.1016/j.sbsr.2024.100725.