Fabrication and characterization of ultrathin dextran layers: Time dependent nanostructure in aqueous environments revealed by OWLS

Andras Saftics, Sándor Kurunczi, Zsolt Szekrényes, K. Kamarás, Nguyen Quoc Khánh, A. Sulyok, Sz. Bősze, R. Horváth

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Surface coatings of the polysaccharide dextran and its derivatives are key ingredients especially in label-free biosensors for the suppression of non-specific binding and for receptor immobilization. Nevertheless, the nanostructure of these ultrathin coatings and its tailoring by the variation of the preparation conditions have not been profoundly characterized and understood. In this work carboxymethylated dextran (CMD) was prepared and used for fabricating ultrathin surface coatings. A grafting method based on covalent coupling to aminosilane- and epoxysilane-functionalized surfaces was applied to obtain thin CMD layers. The carboxyl moiety of the CMD was coupled to the aminated surface by EDC-NHS reagents, while CMD coupling through epoxysilane molecules was performed without any additional reagents. The surface analysis following the grafting procedures consisted of X-ray photoelectron spectroscopy (XPS), attenuated total reflection infrared spectroscopy (ATR-IR), spectroscopic ellipsometry, atomic force microscopy (AFM) and optical waveguide lightmode spectroscopy (OWLS). The XPS and AFM measurements showed that the grafting resulted in a very thin dextran layer of a few nanometers. The OWLS method allowed devising the structure of the interfacial dextran layers by the evaluation of the optogeometrical parameters. The alteration in the nanostructure of the CMD layer with the chemical composition of the silane coverage and the pH of the grafting solution was revealed by in situ OWLS, specifically, lain down chains were found to be prevalent on the surface under neutral and basic conditions on epoxysilylated surfaces. The developed methodologies allowed to design and fabricate nanometer scale CMD layers with well-controlled surface structure, which are very difficult to characterize in aqueous environments using present instrumentations and highly hydrated surface layers.

Original languageEnglish
Pages (from-to)861-870
Number of pages10
JournalColloids and Surfaces B: Biointerfaces
Volume146
DOIs
Publication statusPublished - Oct 1 2016

Fingerprint

dextrans
Dextran
Nanostructures
Optical waveguides
Dextrans
optical waveguides
Spectrum Analysis
Spectroscopy
Fabrication
fabrication
spectroscopy
Photoelectron Spectroscopy
Atomic Force Microscopy
coatings
Coatings
reagents
Atomic force microscopy
X ray photoelectron spectroscopy
photoelectron spectroscopy
atomic force microscopy

Keywords

  • Anisotropy
  • Dextran
  • Grafting
  • OWLS
  • Ultrathin layer

ASJC Scopus subject areas

  • Biotechnology
  • Colloid and Surface Chemistry
  • Physical and Theoretical Chemistry
  • Surfaces and Interfaces

Cite this

Fabrication and characterization of ultrathin dextran layers : Time dependent nanostructure in aqueous environments revealed by OWLS. / Saftics, Andras; Kurunczi, Sándor; Szekrényes, Zsolt; Kamarás, K.; Khánh, Nguyen Quoc; Sulyok, A.; Bősze, Sz.; Horváth, R.

In: Colloids and Surfaces B: Biointerfaces, Vol. 146, 01.10.2016, p. 861-870.

Research output: Contribution to journalArticle

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