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Synthesis and pH-responsive properties of pseudo-peptide containing hydrophobic amino acid grafts

Journal Article


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Abstract


  • Pseudo-peptidic polymers have been synthesised by grafting l-valine (PV), l-leucine (PL) and l-phenylalanine (PP) onto the pendant carboxylic acid moieties of a pH-responsive polyamide, poly(l-lysine isophthalamide). The pH-responsive aqueous solution properties of PV-75, PL-75 and PP-75 with a stoichiometric degree of substitution of 75 mol% have been compared with those of the parent poly(l-lysine isophthalamide) using UV-visible and fluorescence spectroscopy. At low concentrations (≤0.1 mg mL-1), the grafted polymers displayed pH-dependent conformation. The pH at the onset of hydrophobic association (pHh) and the pH range over which association occurred varied significantly between the different amino acid grafts. The pHh values of PV-75, PL-75 and PP-75 at 0.025 mg mL-1 were 6.2, 7.0 and 7.2, respectively. Increasing concentration enhanced intermolecular aggregation. A bis-functional Cy5 derivative, incorporated within the backbones of poly(l-lysine isophthalamide) (polyCy5) and PP-75 (PDP-75), was demonstrated to act as a fluorescence reporter on the state of polymer conformation and aggregation. The intracellular trafficking of PDP-75, examined by confocal microscopy, indicates potential applications of the grafted polymers in drug delivery and medical imaging. © 2009 The Royal Society of Chemistry.

UOW Authors


  •   Chen, Rongjun J. (external author)
  •   Eccleston, M E (external author)
  •   Yue, Zhilian
  •   Slater, Nigel K. H. (external author)

Publication Date


  • 2009

Citation


  • Chen, R., Eccleston, M. E., Yue, Z. & Slater, N. K. H. (2009). Synthesis and pH-responsive properties of pseudo-peptide containing hydrophobic amino acid grafts. Journal of Materials Chemistry, 19 (24), 4217-4224.

Scopus Eid


  • 2-s2.0-67149133356

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=2022&context=scipapers

Ro Metadata Url


  • http://ro.uow.edu.au/scipapers/982

Has Global Citation Frequency


Number Of Pages


  • 7

Start Page


  • 4217

End Page


  • 4224

Volume


  • 19

Issue


  • 24

Abstract


  • Pseudo-peptidic polymers have been synthesised by grafting l-valine (PV), l-leucine (PL) and l-phenylalanine (PP) onto the pendant carboxylic acid moieties of a pH-responsive polyamide, poly(l-lysine isophthalamide). The pH-responsive aqueous solution properties of PV-75, PL-75 and PP-75 with a stoichiometric degree of substitution of 75 mol% have been compared with those of the parent poly(l-lysine isophthalamide) using UV-visible and fluorescence spectroscopy. At low concentrations (≤0.1 mg mL-1), the grafted polymers displayed pH-dependent conformation. The pH at the onset of hydrophobic association (pHh) and the pH range over which association occurred varied significantly between the different amino acid grafts. The pHh values of PV-75, PL-75 and PP-75 at 0.025 mg mL-1 were 6.2, 7.0 and 7.2, respectively. Increasing concentration enhanced intermolecular aggregation. A bis-functional Cy5 derivative, incorporated within the backbones of poly(l-lysine isophthalamide) (polyCy5) and PP-75 (PDP-75), was demonstrated to act as a fluorescence reporter on the state of polymer conformation and aggregation. The intracellular trafficking of PDP-75, examined by confocal microscopy, indicates potential applications of the grafted polymers in drug delivery and medical imaging. © 2009 The Royal Society of Chemistry.

UOW Authors


  •   Chen, Rongjun J. (external author)
  •   Eccleston, M E (external author)
  •   Yue, Zhilian
  •   Slater, Nigel K. H. (external author)

Publication Date


  • 2009

Citation


  • Chen, R., Eccleston, M. E., Yue, Z. & Slater, N. K. H. (2009). Synthesis and pH-responsive properties of pseudo-peptide containing hydrophobic amino acid grafts. Journal of Materials Chemistry, 19 (24), 4217-4224.

Scopus Eid


  • 2-s2.0-67149133356

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=2022&context=scipapers

Ro Metadata Url


  • http://ro.uow.edu.au/scipapers/982

Has Global Citation Frequency


Number Of Pages


  • 7

Start Page


  • 4217

End Page


  • 4224

Volume


  • 19

Issue


  • 24