Ni(II)-modified solid substrates as a platform to adsorb His-tag proteins

Author(s)

Valenti, Laura E. ^[1] ; Martins, Vitor L. ^[2] ; Herrera, Elisa ^[1] ; Torresi, Roberto M. ^[2] ; Giacomelli, Carla E. ^[1]

Affiliation

^[1] Univ Nacl Cordoba, Inst Invest Fis Quim Cordoba INFIQC CONICET UNC, Fac Ciencias Quim, Dept Quim Fis, RA-5000 Cordoba - Argentina

^[2] Univ Sao Paulo, Inst Quim, BR-05508000 Sao Paulo - Brazil

• Document type: Journal article
• Source: JOURNAL OF MATERIALS CHEMISTRY B; v. 1, n. 38, p. 4921-4931, 2013.
• Web of Science Citations: 12

Abstract

This work investigated a simple and versatile modification to a solid substrate to develop electrochemical bio-recognition platforms based on bio-affinity interactions between histidine (His)-tagged proteins and Ni(II) surface sites. Carboxylate (COO)-functionalized substrates were prepared in multiple steps, initiated with an amino-terminated self-assembled monolayer (SAM) on polycrystalline gold. Surface enhanced Raman spectroscopy (SERS), quartz crystal microbalance with dissipation monitoring (QCM-D) and contact angle measurements were used to follow the modification process. Upon completion of the modification process, the surface COO-Ni(II) chelate complex and the coordination mode used to bind the His-tag proteins were characterized by X-ray absorption near-edge spectroscopy (XANES). Finally, the electrochemical stability and response of the modified substrates were evaluated. The versatility of the modification process was verified using silica as the substrate. QCM-D and SERS results indicated that two types of films were formed: a COO-terminated SAM, which resulted from the reduction of previously incorporated surface aldehyde groups, and a physically adsorbed polymeric glutaraldehyde film, which was produced in the alkaline medium. XANES spectral features indicated that COO-Ni(II) formed a non-distorted octahedral complex on the substrate. The electrochemical stability and response towards a redox mediator of the COO-Ni(II)-terminated SAM indicated that this platform could be easily coupled to an electrochemical method to detect bio-recognition events. (AU)

• FAPESP's process: 09/53199-3 - Molecular recognition and energy storage: fundamental studies concerning geometry, size and synthesis effects on the optimization of the chemical properties of electroactive materials
• Grantee: Roberto Manuel Torresi
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 09/09209-4 - Metal electrodeposition in ionic liquids
• Grantee: Vitor Leite Martins
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)