No abstract

Titanium (Ti)-based dental implants with multiscale surface topography have attracted great attention as a promising approach to enhance fixation and long-term stability of the implants, through the synergistic effect of nano- and microscale surface roughness, for accelerated bone regeneration and improved mechanical interlocking. However, structural integrity and mechanical stability of the multiscale roughened Ti surface under deformation need to be considered because significant deformation of dental implants is often induced during the surgical operation. Therefore, in this study, a well-defined nanoporous structure was directly introduced onto micro-roughened Ti surfaces through target-ion induced plasma sputtering (TIPS) with a tantalum (Ta) target, following sand-blasted, large-grit and acid-etching (SLA). This two-step etching process successfully created multiscale surface roughness on Ti with a minimal change of the pre-formed microscale roughness. Moreover, TIPS allowed the Ti surface to possess good mechanical stability under deformation and improved hydrophilicity, through altering the surface chemistry of brittle and hydrophobic SLA-treated Ti without formation of the interface between nanoporous and microporous structures. The in vitro and in vivo tests confirmed that multiscale roughened Ti significantly enhanced osteoblast attachment, proliferation and differentiation, which eventually led to improved bone regeneration and osseointegration, compared to smooth and micro-roughened Ti.

photons can be efficiently converted into electron oscillations in plasmonic nanostructures. [1] The use of plasmonic antennas could substantially enhance the efficiency of many optoelectronic devices by utilizing long-wavelength light beyond the visible region, which accounts for more than a half of the total solar energy. [2] For example, Xiong and co-workers recently developed a flexible near-infrared (NIR) photovoltaic device whose external quantum efficiency (at ≈800 nm) was improved from 24.2% to 38.4% by coupling Si nanowires (NWs) with a Ag-nanoplate-based plasmonic antenna that exhibits a surface plasmon extinction band ranging from 550 to 1100 nm. [2a] Most current plasmonic antennas, however, only enable light trapping in the visible region and within a narrow range. [1c,3] Therefore, for many applications, broadband plasmonic antennas that can work in the NIR region, are highly desired.Upconversion (UC) is an anti-Stokes-type emission process in which the sequential absorption of two or more photons leads to the emission of light at a shorter wavelength than the excitation wavelength. [4] In recent years, rare earth (RE) ion-doped upconversion nanocrystals (UCNCs) have demonstrated great potential in bioimaging and biosensing, infrared photodynamic therapy, 3D display and multiplexing, Plasmonic antennas based on metallic nanostructures that can trap longwavelength light can be used to substantially enhance the efficiency of optoelectronic devices by utilizing light beyond the visible region. This study experimentally and theoretically demonstrates that a silver nanowire network (AgNW-net) plasmonic antenna exhibits superwide surface plasmon extinction because of the strong plasmon coupling between AgNWs, providing the ability to trap light spanning the entire solar spectrum. As a proof-of-concept demonstration, the AgNW-net is used to greatly improve the luminescence of lanthanide-doped upconversion nanocrystals (UCNCs) under dual wavelength excitation and the periodic alternating multilayer structure of AgNWs/ UCNCs is further successfully introduced to improve the absolute luminescence intensity of AgNWs/UCNCs composite films. Furthermore, evidence has been provided that this improvement is attributable to excitation field enhancement rather than Purcell effect or plasmon-enhanced energy transfer. Finally, an upconversion flexible fingerprint identification technology is developed based on AgNW-net/UCNCs/polyvinyl alcohol composite materials, which allows us extracting fingerprints on various uneven bending surfaces.

Achieving single-band upconversion is a challenging but rewarding approach to attain optimal performance in diverse applications, such as multiplexed molecular imaging, security coding, and nonlinear photonic devices. Here, highly efficient single-band upconversion luminescence in the green spectral regime (16.4 times increase in emission at 525 nm) accomplished by realizing minimal energy loss from two-photon upconversion in a newly synthesized liquid-quenched amorphous matrix is reported. In contrast to previously reported single-band upconversion, this phenomenon originates from the elevated transition probability of the host sensitive transition via changes in the host matrix's microstructure. The elevated transition probability facilitates ultrafast decay of upconversion luminescence with decay times as short as 0.2 µs, the fastest decay ever reported. The material in this study therefore has strong potential for use in photonic devices demanding high upconversion efficiency with a fast response time, which to date has been inaccessible using upconversion materials.