Design and development of a novel colorimetric assay and a portable optical system for the detection of aminoglycoside antibiotics

In recent years, environmental contamination with antibiotics has become a severe threat to humankind requiring urgent attention. Presence of incompletely metabolized antibiotics in water bodies, leads to their entry into food chain via live stock and serve as a severe threat to human health. Hence it is imperative that the antibiotics are detected at the source itself. Aminoglycosides are broad spectrum antibiotics known to be more toxic and resistant to multidrug resistant (MDR) organisms compared to other classes of antibiotics. Accordingly in the present work a selective, sensitive and low-cost detection technique for aminoglycoside based antibiotics has been developed. An iron-dependent lipid peroxidation has been explored for the first time to develop a rapid and sensitive colorimetric assay for detecting aminoglycoside antibiotics. A lab-on-chip model (LoC) was designed and developed to miniaturize the colorimetric assay based model for its applications in the real-time analysis of antibiotics. The LoC was integrated with optical fibers, electronic components and associated signal processing circuitry to construct a portable device for antibiotic quantification. Interestingly a selective response towards gentamicin amongst the tested antibiotic was observed. The formation of a colored product within five minutes of reaction time enables a swift and less cumbersome analysis and compared to existing sophisticated analytical techniques. The detection method was validated for gentamicin spiked environmental samples and showed a recovery of more than 90%. This method can serve as a suitable alternative in limited laboratory setups and provides a generic platform for developing a rapid, user-friendly and economical detection methods for environmental monitoring of antibiotics.