Taylor, M; Simoes, F; Smith, J; Genapathy, S; Canning, A; Lledos, M; Chan, W C; Denning, C; Scurr, D J; Steven, R T; Spencer, S J; Shard, A G; Alexander, M R; Zelzer, M (2022) Quantifiable correlation of ToF-SIMS and XPS data from polymer surfaces with controlled amino acid and peptide content. Surface and Interface Analysis, 54 (4). pp. 417-432.

Preview

Text eid9503.pdf - Published Version Available under License Creative Commons Attribution. Download (20MB) | Preview

Abstract

Peptide-coated surfaces are widely employed in biomaterial design but quantifiable correlation between surface composition and biological response is challenging due to e.g. instrumental limitations (detection limits, ability to yield quantifiable data), a lack of suitable model surfaces or limitations in quantitatively correlating data from different surface analytical techniques. Here, we first establish a reference material that allows control over the amino acid content. Reversible-addition fragmentation chain-transfer (RAFT) polymerisation is used to prepare a copolymer containing alkyne and furan units with well-defined chain length and composition. Huisgen Cu(I)-catalyzed azide-alkyne cycloaddition reaction is used to attach the model azido-polyethyleneglycol-amide-modified pentafluoro-l-phenylalanine to the polymer. Different compositional ratios of the polymer provide a surface with systematically varying amino acid content that is analysed by XPS and ToF-SIMS. Nitrogen related signals are compared to fluorine signals from both techniques; both fluorine and nitrogen signals from both techniques are found to be closely related to the copolymer compositions, but the homopolymer data deviates considerably from this trend. The approach is then translated to a heparin binding peptide which supports cell adhesion. Human embryonic stem cells cultured on copolymer surfaces presenting different amounts of heparin binding peptide show strong cell growth while maintaining pluripotency after 72 hours of culture. The early cell adhesion at 24 hours can be correlated closely to the logarithm of the normalised CH4N+ ion intensity from ToF-SIMS data, which is established as a suitable and generalisable marker ion for amino acids and peptides. This work contributes to the ability to use ToF-SIMS in a more quantitative manner for the analysis of amino acid and peptide surfaces.

Item Type:	Article
Keywords:	cell–material interaction, heparin-binding peptide, human embryonic stem cells, peptidepolymer conjugates, surface analysis
Subjects:	Nanoscience > Surface and Nanoanalysis
Divisions:	Chemical & Biological Sciences
Identification number/DOI:	10.1002/sia.7052
Last Modified:	27 Jul 2022 13:58
URI:	https://eprintspublications.npl.co.uk/id/eprint/9503