title: Electrochemical modelling of QD-phospholipid interactions.
abstract: OBJECTIVE
  The aggregation of quantum dots (QDs) and capping of individual QDs affects their activity towards biomembrane models.
  
  
  METHODS
  Electrochemical methods using a phospholipid layer on mercury (Hg) membrane model have been used to determine the phospholipid monolayer activity of thioglycollic acid (TGA) coated quantum dots (QDs) as an indicator of biomembrane activity. The particles were characterised for size and charge.
  
  
  RESULTS
  The activity of the QDs towards dioleoyl phosphatidylcholine (DOPC) monolayers is pH dependent, and is most active at pH 8.2 within the pH range 8.2-6.5 examined in this work. This pH dependent activity is the result of increased particle aggregation coupled to decreasing surface charge emanating from the TGA carboxylic groups employed to stabilize the QD dispersion in aqueous media. Capping the QDs with CdS/ZnS lowers the particles' activity to phospholipid monolayers.
authors.affiliation: School of Chemistry, University of Leeds, Leeds LS2 9JT, UK.
authors.forename: Shengwen
authors.initials: S
authors.lastname: Zhang
authors.affiliation: School of Chemistry, University of Leeds, Leeds LS2 9JT, UK.
authors.forename: Rongjun
authors.initials: R
authors.lastname: Chen
authors.affiliation: School of Chemistry, University of Leeds, Leeds LS2 9JT, UK.
authors.forename: Girish
authors.initials: G
authors.lastname: Malhotra
authors.affiliation: School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK.
authors.forename: Kevin
authors.initials: K
authors.lastname: Critchley
authors.affiliation: School of Chemistry, University of Leeds, Leeds LS2 9JT, UK.
authors.forename: Alexander
authors.initials: A
authors.lastname: Vakurov
authors.affiliation: School of Chemistry, University of Leeds, Leeds LS2 9JT, UK. Electronic address: A.L.Nelson@leeds.ac.uk.
authors.forename: Andrew
authors.initials: A
authors.lastname: Nelson
mesh_terms: D055664:Electrochemical Techniques; D006863:Hydrogen-Ion Concentration; D008567:Membranes, Artificial; D008628:Mercury / Q000737:chemistry; D008956:Models, Chemical; D010743:Phospholipids / Q000737:chemistry*; D045663:Quantum Dots / Q000737:chemistry*; D013864:Thioglycolates / Q000737:chemistry
chemical_list: D008567:Membranes, Artificial; D010743:Phospholipids; D013864:Thioglycolates; C017487:2-mercaptoacetate; D008628:Mercury
keywords: Aggregation; CdTe; CdTe/CdS/ZnS; Phospholipid monolayer; Quantum dots; pH