Treatment of large bone defects derived from bone tumor surgery is typically performed in multiple separate operations, such as hyperthermia to extinguish residual malignant cells or implanting bioactive materials to initiate apatite remineralization for tissue repair; it is very challenging to combine these functions into a material. Herein, we report the first photothermal (PT) effect in bismuth (Bi)-doped glasses. On the basis of this discovery, we have developed a new type of Bi-doped bioactive glass that integrates both functions, thus reducing the number of treatment cycles. We demonstrate that Bi-doped bioglasses (BGs) provide high PT efficiency, potentially facilitating photoinduced hyperthermia and bioactivity to allow bone tissue remineralization. The PT effect of Bi-doped BGs can be effectively controlled by managing radiative and non-radiative processes of the active Bi species by quenching photoluminescence (PL) or depolymerizing glass networks. In vitro studies demonstrate that such glasses are biocompatible to tumor and normal cells and that they can promote osteogenic cell proliferation, differentiation, and mineralization. Upon illumination with near-infrared (NIR) light, the bioglass (BG) can efficiently kill bone tumor cells, as demonstrated via in vitro and in vivo experiments. This indicates excellent potential for the integration of multiple functions within the new materials, which will aid in the development and application of novel biomaterials.
Transparent novel glass-ceramics containing Sr 2 YbF 7 :Er 3+ nanocrystals were successfully fabricated by melt-quenching technique. Their structural and up-conversion luminescent properties were systemically investigated by XRD, HRTEM, and a series of spectroscopy methods. The temperature-dependent upconversion spectra prove that 2 H 11/2 and 4 S 3/2 levels of Er 3+ are thermally coupled energy levels (TCEL). Consequently, the 2
Wideband near‐infrared (NIR)‐emitting materials are of current interest due to their practical utilization in light sources and tunable fiber lasers for optical sensing, imaging, and amplification. Though massive research is devoted to exploring materials activated by rare‐earth ions, transition metals, and semiconductor nanocrystals, the pursuit of photonic materials with ultra‐wideband emission over an extremely wide wavelength range is still not satisfied, especially for transparent amorphous solids which are suitable for active‐fiber applications. Here, such NIR emission is realized via topochemical reduction of bismuth in an amorphous solid. Constructing a local reduction environment around Bi extends its NIR emission to abnormal 0.8–1.9 µm with an incomparable bandwidth of >650 nm, which fully covers the whole NIR region under a single wavelength excitation, that is, from the transparency windows of biological tissue over the technically essential low‐loss optical communication. Furthermore, it is experimentally shown that the same scenario can be reproduced in other typical glass systems. It is anticipated that this strategy should help fundamentally improve the optical performance of Bi‐doped glasses and contribute to exploring new photonic materials.
Wideband NIR-emitting materials are
crucial components in light
sources and tunable lasers for sensing, metrology, and optical amplification.
While traditional rare-earth (RE) doped gain media have reached their
limit in bandwidth, Bismuth-doped glasses have been evolving as an
interesting alternative with unmatched spectral performance. However,
serious issues remain for this type of material, in particular, in
achieving the desired spectral bandwidth while providing the ability
of fiber drawing on part of the matrix glass, and in terms of stabilization
of the active Bismuth center in secondary processing steps at high
temperature. Here, we report on chemical nitridation of Bidoped glasses
as a means to enhance local network rigidity and, thus, stabilize
the NIR active emission species and increase Birelated NIR emission
efficiency. At the same time, we show that the existence of nitride
bonds leads to the emergence of germanium-related Bi emission centers,
which further enhance the spectral bandwidth of Bidoped optical emitters
to >600 nm. Beating previous materials, the emission band envelope
spans the complete NIR region, that is, from the transparency windows
of biological tissue over the low-loss O-band of optical communication
which is hardly accessible with typical RE-based materials to the
more common C- and L-bands. For demonstration purpose, optical fiber
is manufactured from nitridated, Bidoped germanate glass through the
rod-in-tube-technique, with NA ∼ 0.14 and stable NIR emission
from germanium-related Bi emission centers. This shows how nitridation
offers new potential in the design of Bibased optical amplifiers and
tunable lasers, and the exploration of novel photonic materials.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.