A simultaneous qualitative and quantitative lateral flow immunoassay for on-site and rapid detection of streptomycin in pig blood serum and urine

Veterinary antibiotic residues are major contaminants in animal-derived foods and dairy products, and the consumption of contaminated products is associated with severe health risks. Among the wide range of veterinary antibiotics, streptomycin (STR, an aminoglycoside commonly used to treat bacterial infections) is widely administered to livestock. Hence, efficient on-site sensing strategies are required to detect veterinary antibiotics. Using gold nanoparticles (AuNPs), we fabricated a one-step lateral flow immunochromatographic assay (LFIA) for the simultaneous quantitative and qualitative detection of STR in pig serum and urine samples. A specific anti-streptomycin monoclonal antibody was conjugated with AuNPs to fabricate LFIA test strips. Several key parameters were optimized to enhance the sensitivity of the LFIA sensor. The visual limit of detection of the sensor was 5 ng/mL for both serum and urine spiked samples, and cut-off values for serum and urine were 20 ng/ mL and 22 ng/mL, respectively, which demonstrated the developed LFIA sensor is highly sensitive for detecting STR. Furthermore, test strips had good reliability and produced results within 10 min without the need for professional personnel or specialized equipment. We also combined the LFIA test strips with an LFIA reader to obtain quantitative results and assess risk ranges. The success rates of the LFIA reader for serum and urine sample testing were 95.5 % and 91 %, respectively. These results indicate the test strips could be utilized as a significant sensing strategy for semi quantitative, qualitative, and quantitative on-site detection of STR in pig serum and urine samples before slaughter.