Immobilization of enzymes to silver island films for enhanced enzymatic activity

Biebele Abel, Kadir Aslan*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Hypothesis: The performance of the enzyme-based biosensors depends on the enzymatic activity and the use of an appropriate technique for immobilization of enzymes. The incorporation of silver island films (SIFs) into the enzyme-based biosensors is expected to enhance the enzymatic activity and to increase the detectability of analytes of interest. Experiments: Two enzymes, β-galactosidase (β-Gal) and alkaline phosphatase (AP) were immobilized onto SIFs using the interactions of avidin-modified enzymes with (i) a monolayer of biotinylated bovine serum albumin (b-BSA) and/or (ii) a monolayer of biotinylated poly(ethylene-glycol)-amine (BEA molecular weight: 550-10,000. Da). To confirm the effect of SIFs on enzymatic activity, two control surfaces (no silver) were also employed. Findings: No enhancement in enzymatic activity for β-Gal on all SIFs was observed, which was attributed to the inhibition of β-Gal activity due to direct interactions of β-Gal with SIFs. The AP activity on SIFs with BEA was significantly larger than that observed on SIFs with b-BSA, where a 300% increase in AP activity was observed as compared to control surfaces. These observations suggest that SIFs can significantly enhance AP activity, which could help improve the detection limits of ELISAs and immunoassays that employ AP.

Original languageEnglish
Pages (from-to)133-142
Number of pages10
JournalJournal of Colloid and Interface Science
StatePublished - 1 Feb 2014
Externally publishedYes


  • Alkaline phosphatase
  • Biotin-Poly (Ethylene-glycol) Amine
  • Enzymatic activity
  • Enzymes
  • Protein assays
  • Silver island films
  • β-galactosidase


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