Zhongjun Li

Antimonene Quantum Dots: Synthesis and Application as Near‐Infrared Photothermal Agents for Effective Cancer Therapy

Photothermal therapy (PTT) has shown significant potential for cancer therapy. However, developing nanomaterials (NMs)-based photothermal agents (PTAs) with satisfactory photothermal conversion efficacy (PTCE) and biocompatibility remains a key challenge. Herein, a new generation of PTAs based on two-dimensional (2D) antimonene quantum dots (AMQDs) was developed by a novel liquid exfoliation method. Surface modification of AMQDs with polyethylene glycol (PEG) significantly enhanced both biocompatibility and stability in physiological medium. The PEG-coated AMQDs showed a PTCE of 45.5 %, which is higher than many other NMs-based PTAs such as graphene, Au, MoS2 , and black phosphorus (BP). The AMQDs-based PTAs also exhibited a unique feature of NIR-induced rapid degradability. Through both in vitro and in vivo studies, the PEG-coated AMQDs demonstrated notable NIR-induced tumor ablation ability. This work is expected to expand the utility of 2D antimonene (AM) to biomedical applications through the development of an entirely novel PTA platform.

Novel concept of the smart NIR-light–controlled drug release of black phosphorus nanostructure for cancer therapy

Significance Precision delivery of cancer drugs to tumor site is crucial for improving therapeutic efficacy and minimizing adverse effects. Despite tremendous efforts, current drug delivery systems remain an unmet clinical need for cancer therapy. Herein, we propose a unique concept of applying external light to control drug delivery in cancer tissues. In preclinical cancer models, we demonstrate that the near-infrared light-induced decomposition of black phosphorus hydrogel accurately releases drugs in tumor tissues to eradicate subcutaneous breast and melanoma cancers without causing any adverse effects. We believe that our therapeutic system can be used for effective treatment of most cancer types. Our findings may likely bring about a paradigm shift in clinical treatment of cancer and millions of cancer patients will benefit from our findings. A biodegradable drug delivery system (DDS) is one the most promising therapeutic strategies for cancer therapy. Here, we propose a unique concept of light activation of black phosphorus (BP) at hydrogel nanostructures for cancer therapy. A photosensitizer converts light into heat that softens and melts drug-loaded hydrogel-based nanostructures. Drug release rates can be accurately controlled by light intensity, exposure duration, BP concentration, and hydrogel composition. Owing to sufficiently deep penetration of near-infrared (NIR) light through tissues, our BP-based system shows high therapeutic efficacy for treatment of s.c. cancers. Importantly, our drug delivery system is completely harmless and degradable in vivo. Together, our work proposes a unique concept for precision cancer therapy by external light excitation to release cancer drugs. If these findings are successfully translated into the clinic, millions of patients with cancer will benefit from our work.

A black/red phosphorus hybrid as an electrode material for high-performance Li-ion batteries and supercapacitors

A single elemental hybrid composed of black phosphorus (BP) and red phosphorus (RP) is synthesized via a feasible sonochemical method. BP and RP can construct a new single elemental heterostructure. This kind of structure with an excellent interfacial contact between BP and RP would be beneficial to electron transfer and exhibits a superior electrochemical performance. Compared with the sole RP, the as-prepared BP/RP hybrid exhibits enhanced electrochemical performances as an electrode material for both lithium-ion batteries and supercapacitors. For lithium-ion battery applications, the BP/RP hybrid provides a high cycling performance with an initial discharge capacity of 2449 mA h g−1 and a reversible capacity of 491 mA h g−1 after 100 cycles. For supercapacitor applications, the specific capacitance of the BP/RP hybrid achieves a high value up to about 60.1 F g−1 and a long cycling life with a capacity retention of 83.3% after 2000 cycles. The present study demonstrates that the BP/RP hybrid has potential for application as an electrode with high performances in electrochemical energy-storage devices.

Fluorinated Phosphorene: Electrochemical Synthesis, Atomistic Fluorination, and Enhanced Stability

Phosphorene has attracted great interest due to its unique electronic and optoelectronic properties owing to its tunable direct and moderate band-gap in association with high carrier mobility. However, its intrinsic instability in air seriously hinders its practical applications, and problems of technical complexity and in-process degradation exist in currently proposed stabilization strategies. A facile pathway in obtaining and stabilizing phosphorene through a one-step, ionic liquid-assisted electrochemical exfoliation and synchronous fluorination process is reported in this study. This strategy enables fluorinated phosphorene (FP) to be discovered and large-scale, highly selective few-layer FP (3-6 atomic layers) to be obtained. The synthesized FP is found to exhibit unique morphological and optical characteristics. Possible atomistic fluorination configurations of FP are revealed by core-level binding energy shift calculations in combination with spectroscopic measurements, and the results indicate that electrolyte concentration significantly modulates the fluorination configurations. Furthermore, FP is found to exhibit enhanced air stability thanks to the antioxidation and antihydration effects of the introduced fluorine adatoms, and demonstrate excellent photothermal stability during a week of air exposure. These findings pave the way toward real applications of phosphorene-based nanophotonics.

Fundamental and harmonic mode-locking at 21 μm with black phosphorus saturable absorber

We report mode-locking in holmium-doped all-fiber laser based on black phosphorus saturable absorber. The generated solitons are centered at 2094 nm with bandwidth reaching 4.2 nm and pulse duration of 1.3 ps. In harmonic mode-locking, up to 10th harmonic (290 MHz) was obtained. Properties of black phosphorus saturable absorber are investigated. Our findings validate black phosphorus suitability for ultrafast applications in mid-infrared.

Two-dimensional bismuth nanosheets as prospective photo-detector with tunable optoelectronic performance

Two dimensional Bi nanosheets have been employed to fabricate electrodes for broadband photo-detection. A series of characterization techniques including scanning electron microscopy and high-resolution transmission electron microscopy have verified that Bi nanosheets with intact lamellar structure have been obtained after facile liquid phase exfoliation. In the meanwhile, UV-vis and Raman spectra are also carried out and the inherent optical and physical properties of Bi nanosheets are confirmed. Inherited from the topological characteristics of Bi bulk counterpart, the resultant Bi nanosheet-based photo-detector exhibits preferable photo-response activity as well as environmental robustness. We then evaluate the photo-electrochemical (PEC) performance of the photodetector in 1 M NaOH and 0.5 M Na2SO4 electrolytes, and demonstrated that the as-prepared Bi nanosheets may possess a great potential as PEC-type photo-detector. Additional PEC measurements show that the current density of Bi nanosheets can reach up to 830 nA cm-2, while an enhanced responsivity (1.8 μA W-1) had been achieved. We anticipate that this contribution can provide feasibility towards the construction of high-performance elemental Bi nanosheets-based optoelectronic devices in the future.

Black phosphorus analogue tin sulfide nanosheets: synthesis and application as near-infrared photothermal agents and drug delivery platforms for cancer therapy

Two-dimensional (2D) inorganic nanomaterials for biomedical applications still face the challenge of simultaneously offering a high photothermal conversion efficiency (PTCE), efficient drug delivery, biocompatibility and biodegradability. Herein, cancer treatment using tin sulfide nanosheet (SnS NS)-based dual therapy nano-platforms (SDTNPs), including photothermal- and chemo-therapy, is demonstrated. SnS, a black phosphorus (BP) analogue binary IV-VI compound, was synthesized using liquid phase exfoliation. SnS NSs comprising 2-4 layers exhibited good biocompatibility and a high PTCE of 39.3%, which is higher than other popular 2D materials. The SnS NSs showed a stable photothermal performance over 2 h of laser irradiation and exhibited ∼14% degradation after 10 h of irradiation. It was also found that SnS NSs show high loading of small molecules such as doxorubicin (DOX) (up to ∼200% in weight). Consequently, the SDTNPs achieved notable tumor therapy through the combination of photothermal- and chemo-therapy both in vitro and in vivo. Our study may pave the way for the biomedical application of SnS and other IV-VI compound-based 2D nanomaterials. Compared with traditional therapies, SnS NS-based laser therapy is green and efficient, due to its biocompatibility, photo-degradability, high efficiency photothermal properties and high drug loading.

Conceptually Novel Black Phosphorus/Cellulose Hydrogels as Promising Photothermal Agents for Effective Cancer Therapy

Black phosphorus (BP) has recently emerged as an intriguing photothermal agent in photothermal therapy (PTT) against cancer by virtue of its high photothermal efficiency, biocompatibility, and biodegradability. However, naked BP is intrinsically characterized by easy oxidation (or natural degradation) and sedimentation inside the tumor microenvironment, leading to a short-term therapeutic and inhomogeneous photothermal effect. Development of BP-based nanocomposites for PTT against cancer therefore remains challenging. The present work demonstrates that green and injectable composite hydrogels based on cellulose and BP nanosheets (BPNSs) are of great efficiency for PTT against cancer. The resultant cellulose/BPNS-based hydrogel possesses 3D networks with irregular micrometer-sized pores and thin, strong cellulose-formed walls and exhibits an excellent photothermal response, enhanced stability, and good flexibility. Importantly, this hydrogel nanoplatform is totally harmless and biocompatible both in vivo and in vitro. This work may facilitate the development of BP-polymer-based photothermal agents in the form of hydrogels for biomedical-related clinic applications.

A Novel Top-Down Synthesis of Ultrathin 2D Boron Nanosheets for Multimodal Imaging-Guided Cancer Therapy

Single atom nonmetal 2D nanomaterials have shown considerable potential in cancer nanomedicines, owing to their intriguing properties and biocompatibility. Herein, ultrathin boron nanosheets (B NSs) are prepared through a novel top-down approach by coupling thermal oxidation etching and liquid exfoliation technologies, with controlled nanoscale thickness. Based on the PEGylated B NSs, a new photonic drug delivery platform is developed, which exhibits multiple promising features for cancer therapy and imaging, including: i) efficient NIR-light-to-heat conversion with a high photothermal conversion efficiency of 42.5%, ii) high drug-loading capacity and triggered drug release by NIR light and moderate acidic pH, iii) strong accumulation at tumor sites, iv) multimodal imaging properties (photoacoustic, photothermal, and fluorescence imaging), and v) complete tumor ablation and excellent biocompatibility. As far as it is known, this is the first report on the top-down fabrication of ultrathin 2D B NSs by the combined thermal oxidation etching and liquid exfoliation, as well as their application as a multimodal imaging-guided drug delivery platform. The newly prepared B NSs are also expected to provide a robust and useful 2D nanoplatform for various biomedical applications.