Covalent immobilization of protein onto a functionalized hydrogenated diamond-like carbon substrate

Optimized study of the annealing effect on the electrical and structural properties of HDLC thin-films

The plasma-enhanced chemical vapor deposition (PECVD) technique has been utilized for the facile surface deposition of hydrogenated diamond-like carbon (HDLC) thin-films onto Si(100) substrates. The as-deposited film surface is homogenous, free of pinholes, and adheres to the substrate. Annealing of the synthesized HDLC surface in a vacuum was performed in the temperature range of 200 to 1000 °C. A host of instrumental techniques, viz. FTIR spectroscopy, AFM, STM, and EC-AFM, were successfully employed to detect the morphological transformation in the HDLC films upon annealing. EC-AFM studies show irreversible biased behavior after undergoing a surface redox couple reaction and morphological change. Raman spectroscopy was carried out along with STM and EC-AFM to determine the functional nature and conductivity of the annealed surface.

The plasma-enhanced chemical vapor deposition (PECVD) technique has been utilized for the facile surface deposition of hydrogenated diamond-like carbon (HDLC) thin-films onto Si(100) substrates.

Improving frictional properties of DLC films by surface energy manipulation

Surface energy is essential to the friction properties of materials, but until now the investigating scope for DLC films has still been narrow. In this paper, we try to expand the surface energy scope of DLC films to their limits by surface modification and study their influence on friction properties. In this case, we not only control the surface energy of DLC films but also manipulate that of the counter balls, by using piranha etching and octadecyltrichlorosilane (OTS) modification. The surface compositions, wettabilities and friction properties of DLC films and counter balls were investigated. The results indicate that the surface energies of DLC films and counter balls can be adjusted successfully in the ranges of 31.2 to 73.73 mJ m⁻² and 15.69 to 72.93 mJ m⁻², respectively. The frictional tests show that all the as-modified DLC films retain relatively stable friction curves, which derive from their good load-carrying and wear-resistance capabilities. Specifically, the DLC-OH covered with vast oxygen-containing groups shows poor frictional properties, owing to its high surface energy and strong adhesion. In contrast, the DLC-OTS exhibits amazing friction reduction properties, due to its ultra-low surface energy and special film structure.

Surface energy is essential to the friction properties of materials, but until now the investigating scope for DLC films has still been narrow.

Dopamine-assisted rapid fabrication of nanoscale protein arrays by colloidal lithography

The development of cost-effective methodologies for the precise nanometer-scale positioning of biomolecules permits the low-cost production of various biofunctional devices for a range of biomedical and nanotechnological applications. By combining colloidal lithography and the mussel-inspired multifunctional polydopamine coating, we present a novel parallel benchtop method that allows rapid nanoscale patterning of proteins without the need for electrically powered equipment in the fabrication process. The PDA-immobilized binary nanopattern consisting of BSA surrounded by PLL-g-PEG is fabricated over a large area, and the integrity of the pattern is confirmed using AFM and FM.

Bio-initiated light addressable potentiometric sensor for unlabeled biodetection and its MEDICI simulation

A bio-mimetic anchoring strategy based on L-3,4-dihydroxyphenylalanine (L-DOPA) was exploited to activate the surface of light addressable potentiometric sensor (LAPS), with the structure of Si(3)N(4)/SiO(2)/Si. X-Ray photoelectron spectroscopy (XPS) measurements were carried out to ascertain its existence. The protein's immobilization on L-DOPA-initiated LAPS were also tested by our LAPS system. Then L-DOPA-activated LAPS were applied in the unlabeled rabbit anti-mouse immunoglobulin (IgG) detection. The maximum sensitivity of L-DOPA-activated LAPS to antigen (Ag) is about 5.68 nA/p[Ag]. LAPS responses in IgG measurements were from 95 to 180 nA, when the concentration was varied from 0-4 μg mL(-1). These experiments show that L-DOPA is an available material for LAPS surface modifications. At the same time, simulations based on MEDICI (Synopsys™) were performed. The simulated curves are in accordance with experimental data which demonstrate our theoretical analysis for the experimental phenomenon, and indicate the feasibility of simulating biological electronic devices with MEDICI.