Laser-Induced Graphene Enabled Highly Sensitive Lumpy Skin Disease Detection and Vaccine Validation

Lumpy skin disease (LSD), caused by Capripoxvirus, poses significant threats to global livestock due to its high contagion and economic impact. Current diagnostic methods are limited by their dependence on laboratories, while vaccine efficacy monitoring relies on cumbersome virus neutralization tests (VNTs). To address these challenges, a laser-induced graphene (LIG)-based electrochemical immunoassay has been developed for the sensitive detection of LSD and the validation of vaccination. The platform employs recombinant F13L antigen and IgM antibody, configured for dual applications: F13L quantification via IgM-functionalized electrodes and antibody detection using F13L-immobilized surfaces. The biosensor demonstrated exceptional performance, achieving a linear dynamic range of 0.5-5,000 ng mL^-1 (R² = 0.9899) with limits of detection of 0.29 ng mL^-1 for F13L detection and 0.05-300 μg mL^-1 (R² = 0.9875) with limits of detection of 0.04 μg mL^-1 for IgM detection. A pilot clinical validation with 25 bovine sera (naïve, vaccinated, and naturally infected) yielded preliminary estimates of 95% sensitivity and 100% specificity, correlating with ELISA (R² = 0.9387). The 10-min readout and <10% signal loss after 30 days of storage support feasibility in field use. These findings provide feasibility evidence that the platform can support point-of-care LSD surveillance and vaccination assessment. Larger, diverse cohorts are warranted to establish generalizable performance.