Field-Based cDNA-Biosensor for Accurate Detection of Canine Distemper Virus in Tissue Samples

Canine distemper, a viral disease with a global impact on various animals including dogs, foxes, wolves, lions, and leopards, requires early diagnosis for effective treatment and outbreak control. Common laboratory methods, such as enzyme-linked immunosorbent assay, polymerase chain reaction, and viral isolation, face challenges such as extended turnaround times, high costs, and the expertise required. This study has developed a field-based biosensor for detecting the canine distemper virus (CDV), utilising a screen-printed carbon electrode (SPCE) and a computer-assisted portable potentiostat. A 30-mer oligonucleotide capture probe, designed using Primer3 Plus software version 3.3.0, detected hybridisation with the CDV complementary strand through electrochemical analysis via differential pulsed voltammetry. The developed biosensor exhibited good linearity in quantifying the target analyte concentration (0.1 to 12.8 µM), with a detection limit of 0.05 µM, indicating high sensitivity. Specificity tests using complementary and non-complementary sequences confirmed the biosensor's accuracy. The electrode can be reused up to eight times with a residual capacity of 93.72 ± 5.45% after regeneration using a 50 mM NaOH solution. The developed biosensor was also used to detect CDV in biological samples after RNA extraction and amplification. Results from the biosensor aligned with those from reverse transcriptase polymerase chain reaction (RT-PCR) findings, showing 100% agreement. These findings support the potential development of a field-deployable portable device for effectively diagnosing canine distemper in biological samples.