Phospholipid nanofilms for the detection of Rifaximin in solution

Abstract

A preliminary study for the realization of a nanofilm-based sensor for the detection of antibiotic residues is reported. The Langmuir–Blodgett (LB) technology is employed for the construction of an ultra-thin immobilization matrix for Rifaximin (Rfx), an antibiotic widely used in veterinary medicine. Dipalmitoyl phosphatidylglycerol is used as an organic building block of the monolayers constituting the nanofilm. Incorporation of Rfx in the film through specific interactions with the phospholipids is evidenced by UV-Vis spectroscopy and electrochemical measurements. The LB film modified surfaces were used with two different detection methods, i.e. spectrophotometry and cyclic voltammetry. Measurements as a function of Rfx concentration showed that it is possible to reveal the presence of Rfx in solution at a concentration as low as 1 × 10⁻⁸ M. Our results show that the presence of the LB nanofilm promotes migration of the Rfx molecule towards the detection device inducing a rapid response and a significant increase of the detection limit.

Keywords:

• Langmuir–Blodgett films
• Antibiotic
• Nanosensors
• Cyclic voltammetry

Acknowledgements

The work was supported by Ministero dell’ Istruzione, dell’ Universita’ e della Ricerca (MIUR) and by Ministero della Sanita’. The authors wish to thank FATRO (Bologna, Italy) for the supply of Rifaximin. S. Morandi thanks IZS-Ministero della Sanita for partial financial support.