[Research progress on antibacterial properties of porous medical implant materials].

OBJECTIVE: The antibacterial properties of porous medical implant materials were reviewed to provide guidance for further improvement of new medical implant materials. METHODS: The literature related to the antibacterial properties of porous medical implant materials in recent years was consulted, and the classification, characteristics and applications, and antibacterial methods of porous medical implant materials were reviewed. RESULTS: Porous medical implant materials can be classified according to surface pore size, preparation process, degree of degradation in vivo, and material source. It is widely used in the medical field due to its good biocompatibility and biomechanical properties. Nevertheless, the antibacterial properties of porous medical implant materials themselves are not obvious, and their antibacterial properties need to be improved through structural modification, overall modification, and coating modification. CONCLUSION: At present, coating modification as the mainstream modification method for improving the antibacterial properties of porous medical materials is still a research hotspot. The introduction of new antibacterial substances provides a new perspective for the development of new coated porous medical implant materials, so that the porous medical implant materials have a more reliable antibacterial effect while taking into account biocompatibility.

High Quality Plasmonic Sensors Based on Fano Resonances Created through Cascading Double Asymmetric Cavities.

In this paper, a type of compact nanosensor based on a metal-insulator-metal structure is proposed and investigated through cascading double asymmetric cavities, in which their metal cores shift along different axis directions. The cascaded asymmetric structure exhibits high transmission and sharp Fano resonance peaks via strengthening the mutual coupling of the cavities. The research results show that with the increase of the symmetry breaking in the structure, the number of Fano resonances increase accordingly. Furthermore, by modulating the geometrical parameters appropriately, Fano resonances with high sensitivities to the changes in refractive index can be realized. A maximum figure of merit (FoM) value of 74.3 is obtained. Considerable applications for this work can be found in bio/chemical sensors with excellent performance and other nanophotonic integrated circuit devices such as optical filters, switches and modulators.

Fabricating a silicon nanowire by using the proximity effect in electron beam lithography for investigation of the Coulomb blockade effect.

We present an approach to fabricate a silicon nanowire relying on the proximity effect in electron beam lithography with a low acceleration voltage system by designing the exposure patterns with a rhombus sandwiched between two symmetric wedges. The reproducibility is investigated by changing the number of rhombuses. A device with a silicon nanowire is constructed on a highly doped silicon-on-insulator wafer to measure the electronic transport characteristics. Significant nonlinear behavior of current-voltage curves is observed at up to 150 K. The dependence of current on the drain voltage and back-gate voltage shows Coulomb blockade oscillations at 5.4 K, revealing a Coulomb island naturally formed in the nanowire. The mechanism of formation of the Coulomb island is discussed.

Field emission from a periodic amorphous silicon pillar array fabricated by modified nanosphere lithography.

We prepare an array of amorphous silicon nanopillars by using a modified nanosphere lithography method. The fabrication process includes three steps: (1) 70 nm thick a-Si film was deposited on a crystalline silicon substrate; (2) the substrate was coated with a monolayer of polystyrene (PS) spheres to form an ordered structure on the a-Si thin film surface; (3) the sample was etched by reactive ion etching to produce the amorphous silicon pillar array. The results of field emission measurements show a low turn-on electrical field of about 4.5 V microm(-1) at a current density of 10 microA cm(-2). A relatively high current density exceeding 0.2 mA cm(-2) at 9 V microm(-1) was also obtained. The field enhancement factor is calculated to be about 1240 according to the Fowler-Nordheim (FN) relationship. The good field emission characteristics are attributed to the geometrical morphology, crystal structure and the high density of the field emitter of the silicon nanopillar.