Covalent Immobilization of Protein onto a functionalized Hydrogenated Diamond-like Carbon Substrate

Abstract

Hydrogenated diamond-like carbon (HDLC) has an atomically smooth surface that can be deposited on high-surface area substrata and functionalized with reactive chemical groups, providing an ideal substrate for protein immobilization. A synthetic sequence is described involving deposition and hydrogenation of DLC followed by chemical functionalization. These functional groups are reacted with amines on proteins causing covalent immobilization on contact. Raman measurements confirm the presence of these surface functional groups, and Fourier transform infrared spectroscopy (FTIR) confirms covalent protein immobilization. Atomic force microscopy (AFM) of immobilized proteins is reproducible because proteins do not move as a result of interactions with the AFM probe-tip, thus providing an advantage over mica substrata typically used in AFM studies of protein. HDLC offers many of the same technical advantages as oxidized graphene but also allows for coating large surface areas of biomaterials relevant to the fabrication of medical/biosensor devices.

Signature of Misoriented Bilayer Graphenelike and Graphanelike Structure in the Hydrogenated Diamond-Like Carbon Film

“…The HDLC film [3], [5] was heated at a fixed temperature of 1050 • C for 30 min in high vacuum ∼1 × 10 −6 torr and cooled to room temperature after heating. Raman spectra were obtained using a confocal micro Raman spectrometer (LabRAM HR Vis., Horiba Jobin Yvon S.A.S., France).…”

“…The highest performing graphene samples produced by mechanical exfoliation of graphite [2] seem to be not very good for device applications, because of very low specific surface area on the order of few tens of square nanometers per gram. We have demonstrated earlier [3] that hydrogenated diamond-like carbon (HDLC) films, having large specific surface area ∼10 12 nm 2 /g deposited onto a Si (100) substrate and produced by reactive gas-plasma process, are composed of an ordered hexagonal structure of carbon atoms with lattice parameters a = 2.62 Å and c = 6.752 Å different to those present in a hexagonal graphite structure. These lattice parameters are similar under different orientations of the sample.…”

“…Further structural investigation by micro Raman spectroscopy [5] shows that coherency of sp 3 C-H and sp 2 C = C carbons in the HDLC can produce a continuous nonporous thin film (thickness ∼168 nm) having atomically smooth surface. These earlier works [3], [5] motivate us to explore the structure of HDLC films, in order to address the issues related to graphene-based materials. In this paper, we report the experimental signatures of misoriented bilayer graphanelike and graphenelike structure in the as-deposited HDLC film, having some interesting electronic properties.…”

Atomic Hydrogen Storage in a Two-Dimensional Hydrogenated Diamond-Like Carbon Film

“…It was estimated 12,13 that single-layer graphane, a graphene-based material, having very high hydrogen density 10 can be used for hydrogen storage in hydrogen-fuel technologies. A detailed demonstration was provided earlier 14,15 that hydrogenated diamond-like carbon (HDLC) films, having an estimated value 15 of specific surface area ~10 12 nm 2 /g, deposited onto a large area Si (100) substrate at room temperature by reactive gas-plasma process, are composed of an ordered hexagonal structure of carbon atoms with lattice parameters a = 2.62 Å and c = 6.752 Å, different from those present in a hexagonal graphite structure. Figure 2 provides a typical view of HDLC films onto Si substrate.…”

“…Thus, the EEL spectra also confirm hexagonal crystallinity at different depths of the typical 2D-HDLC film (Figure 2). The aim of the present communication is a critical evaluation of the 2D-HDLC film as a system for storage of atomic hydrogen [14][15][16][17] . The basic condition for the realization of hydrogen storage material for practical uses is that it should be reversible, i.e.…”