Development of an oral biosensor for salivary amylase using a monodispersed silver for signal amplification

Austin O. Aluoch, Omowunmi A. Sadik, Gurrinder Bedi

Research output: Contribution to journalArticlepeer-review

25 Scopus citations


An amperometric biosensor for monitoring the level of protein amylase in human saliva is described. A novel design and the preparation of amylase antibodies and antigens, essential for the development of the biosensor, are reported. The biosensor sensing elements comprise a layer of salivary antibody (or antigen) self-assembled onto Au-electrode via covalent attachment. Molecular recognition between the immobilized antibody and the salivary amylase proteins was monitored via an electroactive indicator (e.g., K3Fe(CN) 6) or a monodispersed silver layer present in solution or electrochemically deposited onto the solid electrode. This electroactive indicator was oxidized or reduced and the resulting current change provided the analytical information about the concentration of the salivary proteins. The limit of detection of 1.57 pg/ml was obtained, in comparison to detection limits of 4.95 pg/ml obtained using potassium ferrocyanide as the redox probe and 10 ng/ml obtained using enzyme-linked immunosorbent assay. Cross-reactivity was tested against cystatin antibodies and was found to be less than 2.26%.

Original languageEnglish (US)
Pages (from-to)136-144
Number of pages9
JournalAnalytical Biochemistry
Issue number1
StatePublished - May 1 2005
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology


  • Amperometry
  • Biosensor
  • Cross-reactivity
  • Cystatin
  • Electrochemical biosensor
  • Immunosensor
  • Saliva
  • α-Amylase


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