Nanocuvettes and their application in Escherichia coli detection

Polluted aquifers harboring harmful bacteria such as Escherichia coli (E. coli) can lead to serious health hazards. Hence, rapid and affordable methods for detection of E. coli are important for ensuring public health, especially in rural communities. Photonic crystals (PC) can be used for developing large-scale production of economical, high-sensitivity sensors for use with UV-Vis spectrophotometry. NanoCuvette combines PC slabs with cuvettes, making it suitable for both laboratory and field applications. This study focuses on the development of a protocol for bio-functionalization of a PC waveguide for enhancing the capture and specific detection of E. coli bacteria. Insights were obtained from detailed characterization performed at various stages using scanning electron microscopy, fluorescence microscopy, and atomic force microscopy techniques. Subsequently, a bio-functionalization protocol was developed to enable the use of the PC slab in a NanoCuvette for detection of binding of E. coli bacteria and for quantitatively determining the concentrations of E. coli. The evaluation was performed using a UV-Vis spectrophotometer based on transmission spectroscopy. This preliminary study reveals promising prospects for rapid E. coli detection and quantization in aqueous samples.