Zhongjian Xie

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.

Black-phosphorus-analogue tin monosulfide: an emerging optoelectronic two-dimensional material for high-performance photodetection with improved stability under ambient/harsh conditions

It is widely known that excellent intrinsic electronic and optoelectronic advantages of black phosphorus (BP) make it attractive for applications in transistor, logic and optoelectronic devices. However, easy degradation upon exposure to ambient conditions turns out to be the most critical bottleneck in restricting its practical applications. In order to simultaneously achieve good stability and high device performance, a two-dimensional (2D) size-selected black-phosphorus-analogue (BPA), tin monosulfide nanosheets (SnS Ns), with enhanced chemical stability was successfully fabricated by a facile liquid phase exfoliation (LPE) method, followed by a liquid cascade centrifugation (LCC) technique. Similar to BP, SnS shows thickness modulated bandgap energy. The as-prepared SnS Ns were employed to fabricate working electrodes for photoelectrochemical (PEC)-type broadband photodetection for the first time, and they exhibit an appropriate capacity for a self-powered broadband photoresponse. More importantly, due to the weak polar character of Sn–S bonds, the SnS-based photodetector shows strong long-term temporal and cycling stability of ON/OFF switching behaviour without any external protection not only in regular basic electrolytes but also under strong polar conditions including harsh acidic and neutral electrolytes. We therefore anticipate that SnS as an emerging optoelectronic material might be developed towards versatile applications such as photodetection, sensing and modulation, etc.