A biodegradable two‐dimensional (2D) delivery platform based on loading black phosphorus nanosheets (BPs) with Cas9 ribonucleoprotein engineered with three nuclear localization signals (NLSs) at C ...terminus (Cas9N3) is successfully established. The Cas9N3‐BPs enter cells effectively via membrane penetration and endocytosis pathways, followed by a BPs biodegradation‐associated endosomal escape and cytosolic releases of the loaded Cas9N3 complexes. The Cas9N3‐BPs thus provide efficient genome editing and gene silencing in vitro and in vivo at a relatively low dose as compared with other nanoparticle‐based delivery platforms. This biodegradable 2D delivery platform offers a versatile cytosolic delivery approach for CRISPR/Cas9 ribonucleoprotein and other bioactive macromolecules for biomedical applications.
Cas9 in black: A biodegradable two‐dimensional delivery platform for CRISPR/Cas9 is successfully established. It is based on loading black phosphorus nanosheets with engineered Cas9 ribonucleoprotein, enabling controlled cytosolic release and genome editing with high efficiency.
As a new kind of 2D material, black phosphorus has gained increased attention in the past three years. Although few‐layered black phosphorus nanosheets (BPs) degrade quickly under ambient conditions ...to phosphate anions, which greatly hampers their optical and electronic applications, this property also makes BPs highly biocompatible and biodegradable, and is regarded as an advantage for various biomedical applications. This Concept summarizes the state‐of‐art progresses of BPs, from fabrication and surface modification to biomedical applications. It is expected that BPs with such fascinating properties will encourage more scientists to engage in expanding its biomedical applications by tackling the scientific challenges involved in their development.
Black phosphorus is gaining increasing attention as a new 2D layered material. This Concept summarizes the state‐of‐art progress of few‐layered black phosphorus, from fabrication and surface modification to biomedical applications. Future research paths for the customization of degradation of few‐layer black phosphorus, for potential applications in the biomedical field, are also suggested.
Black phosphorus nanosheets (BPs) are demonstrated to be highly bioactive anti‐cancer agents because of their inherent and selective chemotherapeutic effects. Fast intracellular biodegradation of BPs ...and acute elevation of phosphate anions were observed from different types of cancer cells due to the stronger intracellular oxidative stress and accelerated energy metabolism, but normal cells are not affected. Selective biodegradation of BPs induced G2/M phase arrest and subsequent apoptosis‐ and autophagy‐mediated cell death in cancer cells but not normal cells. The selectivity was superior to that of the traditional chemotherapeutic agent, doxorubicin (DOX). In vivo assessment confirmed the efficiency of BPs in suppressing tumor growth. This study provides insights into nanostructured bioactive anti‐cancer agents and reveals a new direction for nanomedicine research.
Selective chemotherapy: Black phosphorus nanosheets constitute a new type of bioactive anti‐cancer agent. They selectively induce proliferation inhibition, G2/M arrest and apoptotic/autophagic cell death in cancer cells during natural degradation.
Differentiable neural architecture search (DARTS), as a gradient-guided search method, greatly reduces the cost of computation and speeds up the search. In DARTS, the architecture parameters are ...introduced to the candidate operations, but the parameters of some weight-equipped operations may not be trained well in the initial stage, which causes unfair competition between candidate operations. The weight-free operations appear in large numbers, which results in the phenomenon of performance crash. Besides, a lot of memory will be occupied during training supernet, which causes the memory utilization to be low. In this article, a partial channel connection based on channel attention for differentiable neural architecture search (ADARTS) is proposed. Some channels with higher weights are selected through the attention mechanism and sent into the operation space while the other channels are directly contacted with the processed channels. Selecting a few channels with higher attention weights can better transmit important feature information into the search space and greatly improve search efficiency and memory utilization. The instability of network structure caused by random selection can also be avoided. The experimental results show that ADARTS achieved 2.46% and 17.06% classification error rates on CIFAR-10 and CIFAR-100, respectively. ADARTS can effectively solve the problem that too many skip connections appear in the search process and obtain network structures with better performance.
Although polymerase chain reaction (PCR) is the most widely used method for DNA amplification, the requirement of thermocycling limits its non-laboratory applications. Isothermal DNA amplification ...techniques are hence valuable for on-site diagnostic applications in place of traditional PCR. Here we describe a true isothermal approach for amplifying and detecting double-stranded DNA based on a CRISPR-Cas9-triggered nicking endonuclease-mediated Strand Displacement Amplification method (namely CRISDA). CRISDA takes advantage of the high sensitivity/specificity and unique conformational rearrangements of CRISPR effectors in recognizing the target DNA. In combination with a peptide nucleic acid (PNA) invasion-mediated endpoint measurement, the method exhibits attomolar sensitivity and single-nucleotide specificity in detection of various DNA targets under a complex sample background. Additionally, by integrating the technique with a Cas9-mediated target enrichment approach, CRISDA exhibits sub-attomolar sensitivity. In summary, CRISDA is a powerful isothermal tool for ultrasensitive and specific detection of nucleic acids in point-of-care diagnostics and field analyses.
Heterostructures composed of two‐dimensional black phosphorus (2D BP) with unique physical/chemical properties are of great interest. Herein, we report a simple solvothermal method to synthesize ...in‐plane BP/Co2P heterostructures for electrocatalysis. By using the reactive edge defects of the BP nanosheets as the initial sites, Co2P nanocrystals are selectively grown on the BP edges to form the in‐plane BP/Co2P heterostructures. Owing to disposition on the original defects of BP, Co2P improves the conductivity and offers more active electrocatalytic sites, so that the BP/Co2P nanosheets exhibit better and more stable electrocatalytic activities in the hydrogen evolution and oxygen evolution reactions. Our work not only extends the application of BP to electrochemistry, but also provides a new idea to improve the performance of BP by utilization of defects. Furthermore, this strategy can be extended to produce other BP heterostructures to expand the corresponding applications.
In‐plane black phosphorus (BP)/Co2P heterostructures were synthesized using the reactive edge defects of the BP nanosheets as the initial sites. Co2P selectively grown on the BP edges improves the conductivity and offers more active electrocatalytic sites. The BP/Co2P nanosheets exhibit a better and more stable electrocatalytic activity in hydrogen and oxygen evolution reactions.
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.
A basic N‐methyl‐2‐pyrrolidone liquid exfoliation method is described to produce phosphorene with an excellent water stability, controllable size and layer number, as well as in a high yield. Phosphorene with one to four layers exhibits layer‐dependent Raman scattering characteristics thus providing a fast and efficient means for the in situ determination of the thickness of phosphorene.
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 Lg−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.
A liquid exfoliation method based on a combination of probe sonication and bath sonication was adopted to synthesize black phosphorus quantum dots (BPQDs). These displayed a high extinction coefficient of 14.8 Lg−1 cm−1, a photothermal conversion efficiency of 28.4 %, and good biocompatibility, and can thus be used as highly effective photothermal agents for cancer therapy.
Recent high-throughput techniques have generated a flood of biological data in all aspects. The transformation and visualization of multi-dimensional and numerical gene or protein expression data in ...a single heatmap can provide a concise but comprehensive presentation of molecular dynamics under different conditions. In this work, we developed an easy-to-use tool named HemI (Heat map Illustrator), which can visualize either gene or protein expression data in heatmaps. Additionally, the heatmaps can be recolored, rescaled or rotated in a customized manner. In addition, HemI provides multiple clustering strategies for analyzing the data. Publication-quality figures can be exported directly. We propose that HemI can be a useful toolkit for conveniently visualizing and manipulating heatmaps. The stand-alone packages of HemI were implemented in Java and can be accessed at http://hemi.biocuckoo.org/down.php.
Modulation of the electronic structure of metal catalysts is an effective approach to optimize the electrocatalytic activity. Herein, we show a surprisingly strong activation effect of black ...phosphorus (BP) on platinum (Pt) catalysts to give greatly enhanced catalytic activity in the hydrogen evolution reaction (HER). The unique and negative binding energy between BP and Pt leads to spontaneous formation of Pt‐P bonds producing strong synergistic ligand effects on the Pt nanoparticles. No Pt‐P bonds are formed with red phosphorus which is another allotrope of P. By controlling the number of Pt‐P bonds, 3.5‐fold enhancement in the HER activity can be achieved from the BP‐activated Pt catalyst and the activity is 6.1 times higher than that of the state‐of‐the‐art commercial Pt/C catalyst. The BP‐activated Pt catalyst exhibits a current density of 82.89 mA cm−2 with only 1 μg of Pt in 1 m KOH at an overpotential of 70 mV.
Back in black: Surprisingly strong activation effects of black phosphorus (BP) on Pt catalysts and subsequent modulation the surface electronic structure of Pt result in greatly enhanced catalytic activity in the hydrogen evolution reaction (HER).
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