Black phosphorus quantum dots (BPQDs) were synthesized using a liquid exfoliation method that combined probe sonication and bath sonication. With a lateral size of approximately 2.6 nm and a thickness of about 1.5 nm, the ultrasmall BPQDs exhibited an excellent NIR photothermal performance with a large extinction coefficient of 14.8 L g(-1) cm(-1) at 808 nm, a photothermal conversion efficiency of 28.4%, as well as good photostability. After PEG conjugation, the BPQDs showed enhanced stability in physiological medium, and there was no observable toxicity to different types of cells. NIR photoexcitation of the BPQDs in the presence of C6 and MCF7 cancer cells led to significant cell death, suggesting that the nanoparticles have large potential as photothermal agents.
We have developed a generic approach to engineer tubular micro‐/nanostructures out of many different materials (see figure) with tunable diameters and lengths by precisely releasing and rolling up functional nanomembranes on polymers. The technology spans across different scientific fields ranging from photonics to biophysics and we demonstrate optical ring resonators, magneto‐fluidic sensors, remotely controlled microjets and 2D confined channels for cell growth guiding.
Plasma-surface modification (PSM) is an effective and economical surface treatment technique for many materials and of growing interests in biomedical engineering. This article reviews the various common plasma techniques and experimental methods as applied to biomedical materials research, such as plasma sputtering and etching, plasma implantation, plasma deposition, plasma polymerization, laser plasma deposition, plasma spraying, and so on. The unique advantage of plasma modification is that the surface properties and biocompatibility can be enhanced selectively while the bulk attributes of the materials remain unchanged. Existing materials can, thus, be used and needs for new classes of materials may be obviated thereby shortening the time to develop novel and better biomedical devices. Recent work has spurred a number of very interesting applications in the biomedical field. This review article concentrates upon the current status of these techniques, new applications, and achievements pertaining to biomedical materials research. Examples described include hard tissue replacements, blood contacting prostheses, ophthalmic devices, and other products. #
Although phosphorene has attracted much attention in electronics and optoelectronics as a new type of two‐dimensional material, in‐depth investigations and applications have been limited by the current synthesis techniques. Herein, a basic N‐methyl‐2‐pyrrolidone (NMP) liquid exfoliation method is described to produce phosphorene with excellent water stability, controllable size and layer number, as well as in high yield. Phosphorene samples composed of one to four layers exhibit layer‐dependent Raman scattering characteristics thus providing a fast and efficient means for the in situ determination of the thickness (layer number) of phosphorene. The linear and nonlinear ultrafast absorption behavior of the as‐exfoliated phosphorene is investigated systematically by UV–vis–NIR absorption and Z‐scan measurements. By taking advantage of their unique nonlinear absorption, ultrashort pulse generation applicable to optical saturable absorbers is demonstrated. In addition to a unique fabrication technique, our work also reveals the large potential of phosphorene in ultrafast photonics.
Titanium and titanium alloys are key biomedical materials because of their good biocompatibility and mechanical properties. Nevertheless, infection on and around titanium implants still remains a problem which is usually difficult to treat and may lead to eventual implant removal. As a result, preventive measures are necessary to mitigate implant-frelated infection. One important strategy is to render the implant surface antibacterial by impeding the formation of a biofilm. A number of approaches have been proposed for this purpose and they are reviewed in this article.
Photothermal therapy (PTT) offers many advantages such as high efficiency and minimal invasiveness, but clinical adoption of PTT nanoagents have been stifled by unresolved concerns such as the biodegradability as well as long-term toxicity. Herein, poly (lactic-co-glycolic acid) (PLGA) loaded with black phosphorus quantum dots (BPQDs) is processed by an emulsion method to produce biodegradable BPQDs/PLGA nanospheres. The hydrophobic PLGA not only isolates the interior BPQDs from oxygen and water to enhance the photothermal stability, but also control the degradation rate of the BPQDs. The in vitro and in vivo experiments demonstrate that the BPQDs/PLGA nanospheres have inappreciable toxicity and good biocompatibility, and possess excellent PTT efficiency and tumour targeting ability as evidenced by highly efficient tumour ablation under near infrared (NIR) laser illumination. These BP-based nanospheres combine biodegradability and biocompatibility with high PTT efficiency, thus promising high clinical potential.
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