A sensitive quantitative detection technology for tetracycline and erythromycin based on allosteric transcription factors (aTF) using SPR

Antibiotics are extensively utilized in agriculture and livestock farming; however, their environmental residues may foster the proliferation of drug-resistant bacteria and disrupt ecosystems, underscoring the necessity for sensitive detection technologies. Allosteric transcription factors (aTFs) represent a class of proteins that can specifically recognize small molecules and regulate gene expression. Owing to their high specificity and sensitivity, aTFs have been widely adopted in the development of biosensors. This study utilized the properties of allosteric transcription factors to alter their DNA affinity upon ligand binding. By measuring the changes in affinity of TetR and MphR before and after DNA binding using SPR, the study quantitatively analyzed the concentrations of tetracycline and erythromycin. Through SPR technology, quantitative detection of these affinity changes was achieved. Under optimized conditions regarding sample incubation time and system injection time, the affinity values exhibited changes of two orders of magnitude. The detection limits for tetracycline and erythromycin using this technique were determined to be 0.8 nM and 1 nM, respectively. These results indicate that the developed SPR detection method demonstrates high sensitivity and accuracy for detecting tetracycline and erythromycin, making it a promising tool for various applications, including environmental monitoring and quality control.