Surface functionalisation of TiO 2 evanescent waveguide sensor for E.coli monitoring

A. Purniawan*, G. Pandraud, K. A. Vakalopoulos, P. J. French, P. M. Sarro

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

1 Citation (Scopus)


This work reports the surface functionalisation of evanescent waveguide sensors to immobilise E. coli. In biosensors, the surface functionalisation is an important treatment to ensure that the sensor properly detects the cells of interest. In this paper, we study the thin film surface functionalisation of a TiO 2 evanescent waveguide sensor and their effect on light transmission for the early detection of E. coli in post colon surgery. TiO 2 deposited using atomic layer deposition (ALD) is used as waveguide material. Four layers are used in the functionalisation : the self-assembled monolayer (SAM), the protein, 1-ethyl-3-(3-dimethylaminopropyl) (EDC) and the antibodies. Aminopropyltriethoxysilane (APTES) is used as SAM and reacts with -OH group (hydroxyl). The -OH group must be provided on substrate. In order to have the proper -OH group we deposited 10 nm SiO 2 on the waveguides using PECVD and then treated the samples in oxygen plasma chamber for 2 minutes to create the groups. Afterward APTES is immediately applied on the surface after every layers of the functionalisation process. The second layer (Protein A) of the functionalisation is then put on APTES as interlayer. EDC is used as crosslink agent between APTES and antibodies. The light of Superluminescent light emitting diodes (SLEDs) (λ= 1.3 μm, 400 mA) is channelled using an optical fibre into the functionalised waveguides. The transmitted light is measured with a photodiode. The sensitivity of the sensor was evaluated using several different drain fluid concentrations in medium.

Original languageEnglish
Title of host publicationOptical Sensing and Detection II
Publication statusPublished - 2012
Externally publishedYes
EventOptical Sensing and Detection II - Brussels, Belgium
Duration: 16 Apr 201219 Apr 2012

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


ConferenceOptical Sensing and Detection II


  • Antibodies
  • Drain fluid
  • Evanescent waveguide
  • Functionalisation


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