Size-dependent interaction of a 3-arm star poly(ethylene glycol) with two biological nanopores

Eur Phys J E Soft Matter. 2018 Jun 18;41(6):77. doi: 10.1140/epje/i2018-11687-6.


We use two pore-forming proteins, alpha-hemolysin and aerolysin, to compare the polymer size-dependence of ionic current block by two types of ethyleneglycol polymers: 1) linear and 2) 3-arm star poly(ethylene glycol), both applied as a polydisperse mixture of average mass 1kDa under high salt conditions. The results demonstrate that monomer size sensitivity, as known for linear PEGs, is conserved for the star polymers with only subtle differences in the dependence of the residual conductance on monomer number. To explain this absence of a dominant effect of polymer architecture, we propose that PEG adsorbs to the inner pore wall in a collapsed, salted-out state, likely due to the effect of hydrophobic residues in the pore wall on the availability of water for hydration.

Keywords: Polymers: From Adsorption to Translocation - Topical Issue in Memoriam Loïc Auvray (1956-2016).

MeSH terms

  • Adsorption
  • Bacterial Toxins / chemistry*
  • Bacterial Toxins / metabolism
  • Hemolysin Proteins / chemistry*
  • Hemolysin Proteins / metabolism
  • Hydrophobic and Hydrophilic Interactions
  • Nanopores*
  • Osmolar Concentration
  • Polyethylene Glycols / chemistry*
  • Pore Forming Cytotoxic Proteins / chemistry*
  • Pore Forming Cytotoxic Proteins / metabolism
  • Protein Binding


  • Bacterial Toxins
  • Hemolysin Proteins
  • Pore Forming Cytotoxic Proteins
  • Polyethylene Glycols
  • aerolysin