ABSTRACT Polydopamine (PDA) is a biopolymer, which can form uniform thin films on almost all solid substrates as well as at the liquid/air interface. Carbonized polydopamine possesses graphite-like structure and exhibits high electrical conductivity, which makes it a potential carbon-based thin film conductor. However, studies on mechanical behavior of PDA and its derived materials are very limited. In this study, PDA samples were synthesized through self-assembly of dopamine in aqueous solution. Elastic modulus of thin films was measured using the nanoindentation technique. It is shown that the Young’s modulus of PDA thin film increased with increasing heat treatment temperature (up to 600°C). Doping with Cu ions also increased the Young’s modulus of PDA. Furthermore, all PDA thin films, with and without Cu, exhibited creep behavior.
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Application of polydopamine‐coated nylon capillary‐channeled polymer fibers as a stationary phase for mass spectrometric phosphopeptide analysis
Capillary‐channeled polymer (C‐CP) fibers are demonstrated as a selective stationary phase for phosphopeptide analysis via LC–MS. Taking advantage of the oxidative self‐polymerization of dopamine under alkaline conditions, a simple system involving a dilute aqueous solution of 0.2% w/v dopamine hydrochloride in 0.15% w/v TRIS buffer, pH 8.5 was utilized to coat polydopamine onto nylon 6 C‐CP fibers. Confirmation of the polydopamine coating on the fibers (nylon‐PDA) was made through attenuated total reflection‐FTIR (ATR‐FTIR) analysis. Imaging using SEM was also performed to examine the morphology and topography of the nylon‐PDA. Subsequent loading of Fe3+to the nylon‐PDA matrix was confirmed by SEM/energy dispersive X‐ray spectroscopy (SEM/EDX). The Fe3+‐bound nylon‐PDA fibers packed in a microbore column format were tested in the off‐line preconcentration of phosphopeptides from a 1:100 mixture of β‐casein/BSA digests for MALDI‐TOF analysis. The packed column was also installed onto an HPLC system as a platform for the online sample clean‐up and enrichment of phosphopeptides from a 1:1000 mixture of β‐casein/BSA protein digests that were determined by subsequent ESI–MS analysis.
more » « less- PAR ID:
- 10458897
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- ELECTROPHORESIS
- Volume:
- 41
- Issue:
- 3-4
- ISSN:
- 0173-0835
- Page Range / eLocation ID:
- p. 215-224
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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