Immobilization of proteins on self-assembled monolayers

K. Wadu-Mesthrige, N. A. Amro, Gang-yu Liu

Research output: Contribution to journalArticlepeer-review

124 Scopus citations


The immobilization of protein molecules on self-assembled monolayers (SAM) by physical interactions and chemical bonding has been studied using atomic force microscopy (AFM). The proteins used for our investigation are bovine serum albumin (BSA), lysozyme (LYZ), and normal rabbit immunoglobulin G (IgG). The surfaces are methyl-, hydroxyl-, carboxylic acid- and aldehyde-terminated SAMs. We found that BSA and LYZ can be readily immobilized on SAMs at their isoelectric point (IEP). The detailed surface morphology of adsorbed proteins varies with the functionality of the SAMs. The strong hydrophobic interaction at the IEP is attributed to immobilization. If the solution pH is deviated from the IEP, proteins may be attached onto the surface via electrostatic interactions. Covalent binding between the aldehyde-terminated SAM and the H2N-groups in the protein results in immobilization of all three proteins. The individual proteins and their orientations on SAMs are clearly resolved from high-resolution AFM images. The stability and bioactivity of these immobilized proteins are also studied.

Original languageEnglish (US)
Pages (from-to)380-388
Number of pages9
Issue number6
StatePublished - 2000
Externally publishedYes


  • Atomic force microscopy
  • Immobilization of proteins
  • Self-assembled monolayers
  • Surface functionality
  • Surfactants

ASJC Scopus subject areas

  • Instrumentation


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