Cost-effective flow-through nanohole array-based biosensing platform for the label-free detection of uropathogenic E. coli in real time

• Published in: Biosensors & bioelectronics Vol. 106; pp. 105 - 110
• Main Authors: Gomez-Cruz, Juan, Nair, Srijit, Manjarrez-Hernandez, Angel, Gavilanes-Parra, Sandra, Ascanio, Gabriel, Escobedo, Carlos
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 30.05.2018
• Subjects: Biosensing; Nanohole array; Nanoplasmonics; Surface plasmon resonance; Uropathogenic E. coli; Nanohole array; Nanoplasmonics; Surface plasmon resonance; Uropathogenic E. coli; Biosensing
• DOI: 10.1016/j.bios.2018.01.055
• ISSN: 0956-5663

Rapid, inexpensive and sensitive detection of uropathogenic Escherichia coli (UPEC), a common cause of ascending urinary tract infections (UTIs) including cystitis and pyelonephritis, is critical given the increasing number of cases and its recurrence worldwide. In this paper, we present a label-free nanoplasmonic sensing platform, built with off-the-shelf optical and electronic components, which can detect intact UPEC at concentrations lower than the physiological limit for UTI diagnosis, in real time. The sensing platform consists of a red LED light source, lens assembly, CMOS detector, Raspberry Pi interface in conjugation with a metallic flow-through nanohole array-based sensor. Detection is achieved exploiting nanoplasmonic phenomena from the nanohole arrays through surface plasmon resonance imaging (SPRi) technique. The platform has a bulk sensitivity of 212 pixel intensity unit (PIU)/refractive index unit (RIU), and a resolution in the order of 10−6 RIU. We demonstrate capture and detection of UPEC with a detection limit of ~100 CFU/ml – a concentration well below the threshold limit for UTI diagnosis in clinical samples. We also demonstrate detection of UPEC in spiked human urine samples for two different concentrations of bacteria. This work is particularly relevant for point-of-care applications, especially for regions around the world where accessibility to medical facilities is heavily dependent upon economy, and availability. [Display omitted] •Nanoplasmonic biosensor enables label-free detection of uropathogenic E. Coli (UPEC).•The biosensor allows label-free detection in real-time in both PBS and human urine samples.•Detection is achieved at UPEC concentrations below the threshold for UTI diagnosis.•The biosensor is cost-effective and reduces UTI diagnosis to less than 35 min.