Surface Plasmon Resonance and Bending Loss-Based U-Shaped Plastic Optical Fiber Biosensors

• Published in: Sensors (Basel, Switzerland) Switzerland), 2018-02, Vol.18 (2), p.648
• Main Authors: Arcas, Ariadny da S, Dutra, Fábio da S, Allil, Regina C S B, Werneck, Marcelo M
• Format: Article
• Language: English
• Subjects: Bacteria; bacteria detection; bending loss; biosensor; Biosensors; E coli; Escherichia coli; Gold; Laboratories; Luminous intensity; Optical fibers; plastic optical fiber; refractive index; Surface plasmon resonance; U-shaped fiber sensor; Water quality
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s18020648

( ) is a large and diverse bacteria group that inhabits the intestinal tract of many mammals. Most strains are harmless, however some of them are pathogenic, meaning they can make one sick if ingested. By being in the feces of animals and humans, its presence in water and food is used as indicator of fecal contamination. The main method for this microorganism detection is the bacterial culture medium that is time-consuming and requires a laboratory with specialized personnel. Other sophisticated methods are still not fast enough because they require sending samples to a laboratory and with a high cost of analysis. In this paper, a gold-coated U-shaped plastic optical fiber (POF) biosensor for bacteria detection is presented. The biosensor works by intensity modulation principle excited by monochromatic light where the power absorption is imposed by predominant effect of either bending loss or surface plasmon resonance (SPR), depending on the gold thickness. Bacterial selectivity is obtained by antibody immobilization on the fiber surface. The biosensor showed a detection limit of 1.5 × 10³ colony-forming units (CFU)/mL, demonstrating that the technology can be a portable, fast response and low-cost alternative to conventional methodologies for quality analysis of water and food.