Interferometric porous silicon transducers using an enzymatically amplified optical signal

Endre J. Szili, Andrew Jane, Suet P. Low, Martin Sweetman, Peter MacArdle, Sunil Kumar, Roger St C Smart, Nicolas H. Voelcker

Research output: Contribution to journalArticleResearchpeer-review

45 Citations (Scopus)


This paper describes a novel transducer principle converting biomolecular binding events into changes in porous silicon structural colour. An enzyme-catalysed reaction, horseradish peroxidase (HRP) mediated oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB), induced an amplified optical detection signal on an antibody-functionalised porous silicon film, which manifested as significant changes in the Fabry-Pérot fringe pattern. Exposing porous silicon to non-oxidised TMB and oxidised TMB products and measuring the resulting effective optical thickness (EOT) changes of the porous silicon layer, an amplified signal from porous silicon was found, caused by an intermediate radical cation produced during the enzymatic-catalysed oxidation of TMB. Finally, it was shown that this system could be used to detect a human immunoglobulin (IgG) at 0.2 μg/ml. This work may lead to the development of new biosensors where porous silicon acts as the sensing matrix and transducer element. 

Original languageEnglish
Pages (from-to)341-348
Number of pages8
JournalSensors and Actuators B: Chemical
Issue number1
Publication statusPublished - 15 Dec 2011
Externally publishedYes


  • 3,3′,5,5′-Tetramethylbenzidine
  • Horseradish peroxidase
  • Human immunoglobulin
  • Interferometric reflectance spectroscopy
  • Porous silicon

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