Selective detection of bacteria in urine with a long-range surface plasmon waveguide biosensor

Abstract

Experimentation demonstrates long-range surface plasmon polariton waveguides as a useful biosensor to selectively detect gram negative or gram positive bacteria in human urine having a low concentration of constituents. The biosensor can detect bacteria at concentrations of 10(5) CFU/ml, the internationally recommended threshold for diagnostic of urinary tract infection. Using a negative control urine solution of bacterial concentration 1000☓ higher than the targeted bacteria, we obtain a ratio of 5.4 for the positive to negative signals.

Keywords: (130.3120) Integrated optics devices; (170.0170) Medical optics and biotechnology; (170.7230) Urology; (230.7390) Waveguides, planar; (240.6680) Surface plasmons; (250.5403) Plasmonics; (280.1415) Biological sensing and sensors.

Fig. 1

(a) Microscope image at 50☓ magnification of the top portion of die C53B1310 after use. (b) Photograph of the interrogation system. (c) Block diagram of the LRSPP waveguide biosensor interrogation system [©2013 Optical Society of America; adapted from [17].

Fig. 2

(a) Bulk sensing of high concentration and low concentration urine, flow rate = 20 μl/min, laser power = 14.5 dBm, Die C53B1310 first cleaned on 07 Aug 2014. No functionalization (bare Au surface). (b) Use of DIH2O to separate urine from PBSG, flow = 80 μl/min, laser power = 11.1 dBm, Die C53B1310 first cleaned on 23 sept 2015. Surface functionalized with gram negative antibody on protein G.

Fig. 3

(a) Live E.coli detection in PBSG, flow = 20 μl/min, laser power = 14.5 dBm, gram negative antibody surface, bacteria growth time of 4.3 hours in LB Broth. (b) Dead E.coli detection in PBSG, flow = 20 μl/min, laser power = 14.5 dBm, gram negative antibody surface.

Fig. 4

Live E.coli detection in urine, flow = 20 μl/min, laser power = 11.1 dBm, gram negative antibody surface, bacteria growth time of 4.3 hrs in LB broth.

Fig. 5

(a) Live S.epi detection in urine, flow = 20 μl/min, laser power = 14.5 dBm, gram positive antibody surface. (b) Repeat of live S.epi detection in urine, flow = 20 μl/min, laser power = 14.5 dBm, gram positive antibody surface.

Fig. 6

a) Live gram negative bacteria detection with contamination in urine, flow = 20 μl/min, laser power = 14.5 dBm, gram negative antibody surface. b) Repeat of live gram negative bacteria detection in the presence of contamination in urine, flow = 20 μl/min, laser power = 14.5 dBm, gram negative antibody surface.