Shengwen Zhang1, Rongjun Chen1, Girish Malhotra1, Kevin Critchley2, Alexander Vakurov1, Andrew Nelson3. 1. School of Chemistry, University of Leeds, Leeds LS2 9JT, UK. 2. School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK. 3. School of Chemistry, University of Leeds, Leeds LS2 9JT, UK. Electronic address: A.L.Nelson@leeds.ac.uk.
Abstract
HYPOTHESIS: The aggregation of quantum dots (QDs) and capping of individual QDs affects their activity towards biomembrane models. EXPERIMENTS: 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. FINDINGS: 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.
HYPOTHESIS: The aggregation of quantum dots (QDs) and capping of individual QDs affects their activity towards biomembrane models. EXPERIMENTS: 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. FINDINGS: 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: Alex Vakurov; Rik Drummond-Brydson; Nicola William; Didem Sanver; Neus Bastús; Oscar H Moriones; V Puntes; Andrew L Nelson Journal: Langmuir Date: 2022-04-26 Impact factor: 4.331