Covalent functionalization of NiTi surfaces with bioactive peptide amphiphile nanofibers

Timothy D. Sargeant, Mukti S. Rao, Chung Yan Koh, Samuel I Stupp

Research output: Contribution to journalArticle

108 Citations (Scopus)

Abstract

Surface modification enables the creation of bioactive implants using traditional material substrates without altering the mechanical properties of the bulk material. For applications such as bone plates and stents, it is desirable to modify the surface of metal alloy substrates to facilitate cellular attachment, proliferation, and possibly differentiation. In this work we present a general strategy for altering the surface chemistry of nickel-titanium (NiTi) shape memory alloy in order to covalently attach self-assembled peptide amphiphile (PA) nanofibers with bioactive functions. Bioactivity in the systems studied here includes biological adhesion and proliferation of osteoblast and endothelial cell types. The optimized surface treatment creates a uniform TiO2 layer with low levels of Ni on the NiTi surface, which is subsequently covered with an aminopropylsilane coating using a novel, lower temperature vapor deposition method. This method produces an aminated surface suitable for covalent attachment of PA molecules containing terminal carboxylic acid groups. The functionalized NiTi surfaces have been characterized by X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectroscopy (ToF-SIMS), and atomic force microscopy (AFM). These techniques offer evidence that the treated metal surfaces consist primarily of TiO2 with very little Ni, and also confirm the presence of the aminopropylsilane overlayer. Self-assembled PA nanofibers presenting the biological peptide adhesion sequence Arg-Gly-Asp-Ser are capable of covalently anchoring to the treated substrate, as demonstrated by spectrofluorimetry and AFM techniques. Cell culture and scanning electron microscopy (SEM) demonstrate cellular adhesion, spreading, and proliferation on these functionalized metal surfaces. Furthermore, these experiments demonstrate that covalent attachment is crucial for creating robust PA nanofiber coatings, leading to confluent cell monolayers.

Original languageEnglish
Pages (from-to)1085-1098
Number of pages14
JournalBiomaterials
Volume29
Issue number8
DOIs
Publication statusPublished - Mar 2008

Fingerprint

Nanofibers
Amphiphiles
Peptides
Titanium
Nickel
Atomic Force Microscopy
Metals
Adhesion
arginyl-glycyl-aspartyl-serine
Surface treatment
Secondary Ion Mass Spectrometry
Atomic force microscopy
Bone Plates
Substrates
Photoelectron Spectroscopy
Coatings
Carboxylic Acids
Vapor deposition
Osteoblasts
Stents

Keywords

  • APTES
  • Biofunctionalization
  • Covalent attachment
  • Nickel-titanium
  • Peptide amphiphile nanofibers
  • Self-assembly

ASJC Scopus subject areas

  • Biotechnology
  • Bioengineering
  • Biomedical Engineering

Cite this

Covalent functionalization of NiTi surfaces with bioactive peptide amphiphile nanofibers. / Sargeant, Timothy D.; Rao, Mukti S.; Koh, Chung Yan; Stupp, Samuel I.

In: Biomaterials, Vol. 29, No. 8, 03.2008, p. 1085-1098.

Research output: Contribution to journalArticle

Sargeant, Timothy D. ; Rao, Mukti S. ; Koh, Chung Yan ; Stupp, Samuel I. / Covalent functionalization of NiTi surfaces with bioactive peptide amphiphile nanofibers. In: Biomaterials. 2008 ; Vol. 29, No. 8. pp. 1085-1098.
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