Identification of aminoglycoside antibiotics in milk matrix with a colorimetric sensor array and pattern recognition methods

Aminoglycoside antibiotics (AAs) abused in animal husbandry can cause antibiotic residues in animal-derived foods, which do harm to human beings' health. Therefore the detection of AAs residues in the animal-origin foods, such as milk, eggs and meat is necessary. We used two single-stranded DNA (ssDNA) oligonucleotides as nonspecific receptors to develop a simple colorimetric sensor array based on gold nanoparticles (AuNPs) for identification and quantification the AAs. Different AA addition triggered the DNA detaching from AuNPs then resulted in different degree salt induced aggregation of AuNPs. The aggregation induced spectral changes of AuNPs with five AA addition were analyzed based on pattern recognition techniques, fisher linear discriminant analysis (FLD) and hierarchical cluster analysis (HCA). The results indicated that colorimetric sensor array has successfully identified five AAs at a concentration range of 120-280 nM. Five AAs in aqueous solution and complex milk matrix can be identified with an accuracy of 100%. More importantly, our developed sensor array is sufficiently sensitive for the discrimination of pure streptomycin (STR), binary mixtures of STR and gentamicin (GEN) at a total concentration of 120 nM.