Optical biosensors for the fast detection of pathogenic bacteria

Abstract

Due to the excessive and indiscriminate use of antibiotics, the number of microorganisms resistant to these drugs has progressively increased and become a threat to global public health. Nowadays, infectious diseases outnumber all cancers in terms of mortality. One of the major challenges related to this problem is the development of diagnostic tests for rapid and early detection of these bacteria so infected patients can be easily identified and appropriate treatment protocols are implemented quickly and efficiently. Thus, the present project proposes the development of a portable, efficient and easy-to-use optical sensor for the antibiotic resistant bacteria detection and quantification. Considering all the advantages associated with its absorption in the infrared region, the upconverting nanoparticles (UCNPs) will be used as fluorescence transducers and the system will be based on Luminescent Resonant Energy Transfer (LRET) pairs, where UCNPs act as donors and are conjugated with energy acceptors materials. The nanoparticles will be functionalized with biomolecules according to the pathogens of interest, tested in solution and later a paper-based system will be developed. The final proposal of the project is to create a paper-based biosensor in a way the detection and quantification of the signal can be performed through digital images obtained by smartphones. The sensor will be developed through an in-depth study of the different steps involved in the production of such a platform: (1) synthesis and characterization of UCNPs with high luminescence efficiency; (2) nanoparticles functionalization for detection of microorganisms; (3) study and optimization of the sensing system in solution followed by; (4) evaluation of different approaches for the paper-based tests and; (5) feasibility studies of using digital cellular images for identification and quantification of the response. (AU)