Biorelevant Calcification and Non‐Cytotoxic Behavior in Silicon Nanowires

Abstract

ExperimentalGlassy solid electrolytes in the Li 2 S±P 2 S 5 system were prepared by the mechanical milling technique [13]. Highly pure Li 2 S (Idemitsu Kosan Co., > 99.9 %) and reagent-grade P 2 S 5 (Aldrich, 99 %) crystalline powders were used as starting materials to prepare the 70Li 2 S´30P 2 S 5 (70 mol-% Li 2 S, 30 mol-% P 2 S 5 ) samples. The mixture of these materials was mechanically milled at room temperature by a planetary ball-mill apparatus (Fritsch Pulverisette 7) using an alumina pot (volume of 45 mL) with ten alumina balls (10 mm in diameter); the milling time was 20 h and the rotation speed was 370 rpm. All the processes were performed in a dry, Ar-filled glove box (less than 1 ppm water). Glass-ceramic solid electrolytes were prepared by crystallization of the mechanically milled glass at 240 C for 2 h. Crystalline solid electrolytes with the same composition were prepared by a conventional solid-state reaction in which a mixture of Li 2 S and P 2 S 5 was put into a carbon-coated quartz tube and sealed under vacuum. The tube was heated at 700 C for 8 h, and then slowly cooled to room temperature.Electrical conductivities of pellets obtained by cold pressing the sample under a pressure of 3700 kg cm ±2 were measured; the diameters and thicknesses of the pellets were 10 mm and about 1 mm, respectively. A carbon paste was painted onto both sides of the sample and carbon electrodes were formed after heat treatment. Alternating current (AC) impedance measurements were carried out in a dry argon atmosphere using an impedance analyzer (SI1260, Solartron) in the frequency range of 10 Hz to 8 MHz. The temperature of the measurements ranged from 25 to 240 C. X-ray diffraction (XRD) measurements (Cu Ka) were performed using a diffractometer (M18XHF 22-SRA, MAC Science) to identify crystals in the glass-ceramics. Local structures of the samples were analyzed by Raman spectroscopy using a spectrometer (NR-1000, JASCO) equipped with an Ar + laser (514.5 nm).

Long‐Term Antimicrobial Effect of Silicon Nanowires Decorated with Silver Nanoparticles

“…Nagesha and coworkers have reported that SiNWs were non-cytotoxic to human kidney fi broblasts [ 28 ] and vertically aligned SiNW arrays provide a biocompatible interface for mammalian cell culture. [29][30][31] Given that AgNPs can readily decorate SiNWs, we reason that this process could provide a green approach to develop antibacterial materials with desirable biocompatibility.…”

Graphene–Biomineral Hybrid Materials

“…The osteoconductivity of a material is widely assessed in vitro by measuring the rate of apatite formation in a SBF solution. [33][34][35] We found that lath-like bone HAp crystals formed in both hybrid fi lms ( Figure 3 A-b,B-b) after 4 d of incubation, in contrast to bare GO and graphene that does not undergo any further phase transition in aqueous solution. [ 10 ] The overall structure of CaCO 3 vaterite microspheres, which were wrapped by a GO or graphene network, was well preserved after the reduction process ( Figure S5, Supporting Information).…”

In Vitro Biocompatibility of n‐Type and Undoped Silicon Nanowires

“…[4][5][6] Apart from the application of SiNW-based transistors for the selective detection of biomolecules, relatively little has been reported on the biocompatibility of SiNWs that is necessary for evaluating potential applications of SiNWs as a biomaterial. SiNWs can be considered as a biomaterial because it possesses advantages over other inorganic materials such as polycrystalline metals [7] and significantly, the degradation products of Si nanomaterials are metabolically tolerant in vivo and are found mainly in the form of Si(OH) 4 . [7,8] Nagesha et al [7] have shown SiNW surface under influence of an electrical bias exhibits an interfacial behavior that promotes calcification in stimulated plasma and have demonstrated non-cytotoxic behavior using human kidney fibroblast cells.…”

“…SiNWs can be considered as a biomaterial because it possesses advantages over other inorganic materials such as polycrystalline metals [7] and significantly, the degradation products of Si nanomaterials are metabolically tolerant in vivo and are found mainly in the form of Si(OH) 4 . [7,8] Nagesha et al [7] have shown SiNW surface under influence of an electrical bias exhibits an interfacial behavior that promotes calcification in stimulated plasma and have demonstrated non-cytotoxic behavior using human kidney fibroblast cells. Popat et al [9] have investigated improved osteoblast performance by using controlled SiNW structures.…”