Detection Of Antibiotic Residues In Dairy Products By Aptamer Sensing Method Based On Long Afterglow And Gold Nanomaterials

Dairy products are one of the most globally consumed foods,rich in nutrients such as fat,protein,and calcium.However,illegal traders in the dairy industry abuse aminoglycoside antibiotics to treat cows with mastitis and other diseases,resulting in antibiotic residues in dairy products and potential threats to food safety.Dairy products with antibiotic residues can increase bacterial resistance in the human body.Development of new,rapid,sensitive,and simple detection methods for antibiotic residues in dairy products is crucial for food safety.Although traditional detection techniques are effective in detecting antibiotics,they have some shortcomings such as complex pre-processing,high cost,and the requirement of skilled personnel.Fluorescence-based detection methods are widely used in detecting antibiotic residues in dairy products,but proteins have inherent fluorescence that can interfere with the accuracy of fluorescence detection.Therefore,developing new antibiotic detection methods that are rapid,simple,and have no background fluorescence interference is essential for ensuring dairy product safety.Persistent luminous nanoparticles(PLNPs)have unique persistent luminescence properties that can avoid interference from complex sample matrices’ spontaneous fluorescence,which can improve detection sensitivity and accuracy.This study aimed to construct two rapid and sensitive detection methods based on the unique afterglow luminescence properties of PLNPs and the fluorescence resonance energy transfer system with gold nanoparticles(AuNPs)for detecting antibiotic residues in dairy products.The main research results are as follows:(1)A method for detecting kanamycin(KAN)based on long afterglow fluorescence resonance energy transfer was constructed.Zn2GeO4:Mn2+ PLNPs modified with KAN aptamers and AuNPs modified with complementary DNA were regarded as energy donor and the energy acceptor respectively.The high sensitivity and specificity of the established method were depended on the no background interference of PLNPs and high sensitivity of aptamer.The method showed a good linear relationship between KAN concentration in the range of 0.4-32 μg L-1 and the change in the phosphorescence intensity,and the limit of detection(LOD)was 0.0807μg L-1.The method was used to determine KAN in dairy products,and the recovery rate ranged in 94.30%-102.31%,and the relative standard deviation(RSD)was 0.72%-6.70%.(2)A colorimetric and phosphorescence dual-mode detection method based on the Apt-AuNPs-PLNPs was established for detecting tobramycin(TOB).The colorimetric mode relied on the aggregation of AuNPs induced by competitive binding of TOB and Apt at high salt concentrations and can detect multiple samples efficiently.The colorimetric mode showed a good linear relationship in the range of 5-45 μg L-1,and the LOD was 1.04 μg L-1,with an average recovery of 90.92%-104.30%and an RSD of 0.29%-3.69%.The phosphorescence mode showed a good linear relationship in the range of 1.33-26.67 μg L-1,with an LOD of 2.48 ng L-1,an average recovery of 94.28%-105.19%,and an RSD of 1.15%-4.09%.The sensitivity and selectivity of TOB residues in dairy products were demonstrated,proving the method’s feasibility in dairy product analysis.This article provides new ideas for the rapid,sensitive,and background fluorescence-free detection of aminoglycoside antibiotics in dairy products using AuNPs and PLNPs to construct two different phosphorescence sensing methods.