Recycled additive manufacturing filaments with mixed carbon (nano)materials for human monkeypox virus detection

The development of an additive manufacturing genosensor device for the biosensing of the human monkeypox virus (MPXV) is described. A bespoke filament was fabricated using recycled polylactic acid (PLA), castor oil, and mixed carbon (nano)materials (i.e., carbon black, multiwalled carbon nanotubes, and graphite), enabling the exploration of the advantages of each filler to improve bioreceptor immobilization and biosensor performance. Electrodes printed from the bespoke filament exhibited improved electron transfer rates, electrical conductivity, electroactive area, electrochemical performance, and stability compared to electrodes printed from a commercial filament. The proposed label-free genosensor achieved a linear range of 0.1-5.0 μmol L^-1, sensitivity of 28.2 μAL μmol^-1, limit of detection of 27 nmol L^-1 for the MPXV ssDNA target, and long-term stability over 4 weeks. The device also showed excellent ability to distinguish between negative and positive human blood serum and oropharyngeal swab samples, achieving recoveries of 94.7-106%. Thus, this study establishes a sustainable and versatile bespoke filament as a promising platform for advanced biosensing applications.