Transfer of immunochemical biolayers from sensor chip surface to gold na-noparticles for rapid determination of chloramphenicol in milk

Introduction. Development of rapid tests for monitoring antibiotic residues in livestock products is an urgent task of veterinary and sanitary expertise. Immunochromatographic test strips using gold nanoparticles are widely employed due to their simplicity and speed; however, optimization of multicomponent receptor layers on nanoparticle surfaces remains a laborious process. Purpose: The aim of this study was to investigate the feasibility of transferring immunochemical biolayers, optimized on a flat sensor chip surface of a label-free biosensor, directly onto gold nanoparticles for creating an immunochromatographic rapid test for chloramphenicol. Materials and methods. Protein conjugates of bovine serum albumin with biotin and chloramphenicol of three compositions were immobilized on glass sensor chip surfaces and, in parallel, on gold nanoparticles. Biolayer performance on the chip was monitored by spectral-phase interferometry, and on nanoparticles ‒ in immunochromatographic format. Results and discussion. It was established that chloramphenicol detection results on flat surface and on nanoparticles coincide for all three conjugate types, including the correctly functioning balanced composition and two variants with disrupted balance producing false results. This demonstrates direct transferability of optimization results from chip to nanoparticles. Conclusion. It was shown that label-free optimization of biolayers on a flat sensor chip can serve as a rapid platform for designing immunochromatographic tests for chloramphenicol, significantly accelerating the development of rapid veterinary and sanitary control tools.