Monitoring Microalgae Population Growth by using Fe3O4 Nanoparticles-based Surface Plasmon Resonance (SPR) Biosensor

Abstract

The population growth of microalgae has been successfully monitored by using the surface plasmon resonance (SPR)-based biosensor activated by using PEG-4000 functionalized Fe3O4 magnetic nanoparticles. The SPR-based biosensor in this work used Kretchmann configuration and Ha-Ne laser beam (λ = 633nm). The population of microalgae were estimated by using calibration curve. The shift of SPR angle happens due to the change of dielectric medium from prism/Au/air system to prism/Au/Fe3O4+PEG+microalgae/cover glass system. The change of dielectric medium occurs due to deposition of Fe3O4+PEG+microalgae samples that were monitored for seven days. The population of microalgae on the first day was estimated of 1188146 cell/ml and SPR angle had shifted from 42.80 to 69.00. The SPR angle shifted as much as 26.20. The population of microalga grew significantly on the third day as much as 1649106 cell/ml and the SPR angle had shifted 43.80 to 71.10. The SPR angle shifted as much as 27.30. On fourth to seventh day, the population of microalgae decreased. The population of microalgae on the seventh day was estimated of 1206961 cell/ml and the SPR angle had shifted from 44.00 to 68.80. The SPR angle shifted as much as 24.8 degrees. The shift of SPR angle was influenced by the population of microalgae so that the SPR-based biosensor has the potential for use in monitoring the microalgae population.