On Chip Protein Pre-Concentration for Enhancing the Sensitivity of Porous Silicon Biosensors

Sofia Arshavsky-Graham, Naama Massad-Ivanir, Federico Paratore, Thomas Scheper, Moran Bercovici, Segal Ester H.

Research output: Contribution to journalArticlepeer-review


Porous silicon (PSi) nanomaterials have been widely studied as label-free optical biosensors for protein detection. However, these biosensors' performance, specifically in terms of their sensitivity (which is typically in the micromolar range), is insufficient for many applications. Herein, we present a proof-of-concept application of the electrokinetic isotachophoresis (ITP) technique for real-time preconcentration of a target protein on a PSi biosensor. With ITP, a highly concentrated target zone is delivered to the sensing area, where the protein target is captured by immobilized aptamers. The detection of the binding events is conducted in a label-free manner by reflective interferometric Fourier transformation spectroscopy (RIFTS). Up to 1000-fold enhancement in local concentration of the protein target and the biosensor's sensitivity are achieved, with a measured limit of detection of 7.5 nM. Furthermore, the assay is successfully performed in complex media, such as bacteria lysate samples, while the selectivity of the biosensor is retained. The presented assay could be further utilized for other protein targets, and to promote the development of clinically useful PSi biosensors.

Original languageEnglish
Pages (from-to)1767-1773
Number of pages7
JournalACS Sensors
Issue number12
StatePublished - 22 Dec 2017


  • aptamer
  • isotachophoresis
  • label-free
  • optical biosensor
  • porous silicon

All Science Journal Classification (ASJC) codes

  • Bioengineering
  • Instrumentation
  • Process Chemistry and Technology
  • Fluid Flow and Transfer Processes


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