Nanostructured porous si optical biosensors: Effect of thermal oxidation on their performance and properties

Giorgi Shtenberg, Naama Massad-Ivanir, Ljiljana Fruk, Ester Segal

Research output: Contribution to journalArticlepeer-review

Abstract

The influence of thermal oxidation conditions on the performance of porous Si optical biosensors used for labelfree and real-time monitoring of enzymatic activity is studied. We compare three oxidation temperatures (400, 600, and 800 °C) and their effect on the enzyme immobilization efficiency and the intrinsic stability of the resulting oxidized porous Si (PSiO2), Fabry-Pérot thin films. Importantly, we show that the thermal oxidation profoundly affects the biosensing performance in terms of greater optical sensitivity, by monitoring the catalytic activity of horseradish peroxidase and trypsinimmobilized PSiO2. Despite the significant decrease in porous volume and specific surface area (confirmed by nitrogen gas adsorption-desorption studies) with elevating the oxidation temperature, higher content and surface coverage of the immobilized enzymes is attained. This in turn leads to greater optical stability and sensitivity of PSiO2 nanostructures. Specifically, films produced at 800 °C exhibit stable optical readout in aqueous buffers combined with superior biosensing performance. Thus, by proper control of the oxide layer formation, we can eliminate the aging effect, thus achieving efficient immobilization of different biomolecules, optical signal stability, and sensitivity.

Original languageEnglish
Pages (from-to)16049-16055
Number of pages7
JournalACS Applied Materials and Interfaces
Volume6
Issue number18
DOIs
StatePublished - 24 Sep 2014

Keywords

  • Biosensor
  • Enzyme
  • Label free
  • Nanostructure
  • Porous Si
  • Thermal oxidation

All Science Journal Classification (ASJC) codes

  • General Materials Science

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