Analysis of the surface density and reactivity of perfluorophenylazide and the impact on ligand immobilization

Abstract

Perfluorophenylazide (PFPA) chemistry is a novel method for tailoring the surface properties of solid surfaces and nanoparticles. It is general and versatile, and has proven to be an efficient way to immobilize graphene, proteins, carbohydrates, and synthetic polymers. The main thrust of this work is to provide a detailed investigation on the chemical composition and surface density of the PFPA tailored surface. Specifically, gold surfaces were treated with PFPA-derivatized (11-mercaptoundecyl)tetra(ethylene glycol) (PFPA-MUTEG) mixed with 2-[2-(2-mercaptoethoxy)ethoxy]ethanol (MDEG) at varying solution mole ratios. Complementary analytical techniques were employed to characterize the resulting films including Fourier transform infrared spectroscopy to detect fingerprints of the PFPA group, x-ray photoelectron spectroscopy and ellipsometry to study the homogeneity and uniformity of the films, and near edge x-ray absorption fine structures to study the electronic and chemical structure of the PFPA groups. Results from these studies show that the films prepared from 90:10 and 80:20 PFPA-MUTEG/MDEG mixed solutions exhibited the highest surface density of PFPA and the most homogeneous coverage on the surface. A functional assay using surface plasmon resonance with carbohydrates covalently immobilized onto the PFPAmodified surfaces showed the highest binding affinity for lectin on the PFPA-MUTEG/MDEG film prepared from a 90:10 solution.

Pristine graphene covalent functionalization with aromatic aziridines and their application in the sensing of volatile amines – an ab initio investigation

“…7 One of the various methods for achieving band-gap opening is chemical functionalization using reactive species such as organic cations, radicals, nitrenes and carbenes. [8][9][10][11][12][13][14][15][16] In this respect, reaction with aryl nitrene, generated by thermal or photochemical decomposition of organic precursors, 17 leads to a [2 + 1]-cycloaddition reaction involving two adjacent carbon atoms from the graphene surface and reactive nitrogen to form an aziridine appended to the graphene. [18][19][20][21][22][23] This functionalization causes the re-hybridization of the involved carbon atoms from the sp 2 to sp 2+h state (h: degree of additional hybridization).…”

Functionalization of pristine graphene for the synthesis of covalent graphene–polyaniline nanocomposite

“…6e), the peak at $401 eV is characteristic of the N in the PFPA-functionalized graphene. 40,55,56 The peak at $400 eV can be attributed to the aniline N 57 and the amide N in PFPA-ANI. 55 Polymerization of ANI under the acidic oxidative condition gave the green emeraldine salt of PANI, which consists of unprotonated and protonated aniline structures with the N 1s binding energies at 399.3 eV and 401 eV, respectively.…”

Fabrication of carbohydrate microarrays on a poly(2-hydroxyethyl methacrylate)-based photoactive substrate

“…[51][52][53] PFPA was introduced on wafers or glass slides by treating these substrates with a silane-functionalized PFPA (Scheme S-1 †). 54,55 Polymer solutions were then manually printed on the PFPA-functionalized surfaces followed by irradiation to covalently attach the polymer with the aid of PFPA. The polymer arrays were then treated with FITC labeled Con A (FITC-Con A), and the fluorescence intensities were measured using a microarray scanner.…”