Selective detection of bacteria in urine with a LRSPP waveguide biosensor

Laboratory experimentation demonstrates long range surface plasmon polaritons (LRSPP) waveguides as a useful biosensor to selectively detect gram negative bacteria in human urine. The biosensor can detect bacteria at concentrations of 10 CFU/ml, the internationally recommended threshold for diagnostic of urinary tract infection (UTI). Using a negative control solution at bacterial concentration 1000 X higher than the targeted bacteria in urine with a weak concentration of constituents, the power ratio between the negative control signal to the target bacteria signal is measured to be 6.7 on the first test and 2.5 for a lower bacterial concentration after regenerating the surface with SDS. Hence we report a conclusive demonstration of the LRSPP waveguide biosensor selectivity to the gram of bacteria in human urine.