Polydopamine-Modified 2D Iron (II) Immobilized MnPS3 Nanosheets for Multimodal Imaging-Guided Cancer Synergistic Photothermal-Chemodynamic Therapy.

Manganese phosphosulphide (MnPS3 ), a newly emerged and promising member of the 2D metal phosphorus trichalcogenides (MPX3 ) family, has aroused abundant interest due to its unique physicochemical properties and applications in energy storage and conversion. However, its potential in the field of biomedicine, particularly as a nanotherapeutic platform for cancer therapy, has remained largely unexplored. Herein, a 2D "all-in-one" theranostic nanoplatform based on MnPS3 is designed and applied for imaging-guided synergistic photothermal-chemodynamic therapy. (Iron) Fe (II) ions are immobilized on the surface of MnPS3 nanosheets to facilitate effective chemodynamic therapy (CDT). Upon surface modification with polydopamine (PDA) and polyethylene glycol (PEG), the obtained Fe-MnPS3 /PDA-PEG nanosheets exhibit exceptional photothermal conversion efficiency (η = 40.7%) and proficient pH/NIR-responsive Fenton catalytic activity, enabling efficient photothermal therapy (PTT) and CDT. Importantly, such nanoplatform can also serve as an efficient theranostic agent for multimodal imaging, facilitating real-time monitoring and guidance of the therapeutic process. After fulfilling the therapeutic functions, the Fe-MnPS3 /PDA-PEG nanosheets can be efficiently excreted from the body, alleviating the concerns of long-term retention and potential toxicity. This work presents an effective, precise, and safe 2D "all-in-one" theranostic nanoplatform based on MnPS3 for high-efficiency tumor-specific theranostics.

Biodegradable Bi2 O2 Se Quantum Dots for Photoacoustic Imaging-Guided Cancer Photothermal Therapy.

As new 2D layered nanomaterials, Bi2 O2 Se nanoplates have unique semiconducting properties that can benefit biomedical applications. Herein, a facile top-down approach for the synthesis of Bi2 O2 Se quantum dots (QDs) in a solution is described. The Bi2 O2 Se QDs with a size of 3.8 nm and thickness of 1.9 nm exhibit a high photothermal conversion coefficient of 35.7% and good photothermal stability. In vitro and in vivo assessments demonstrate that the Bi2 O2 Se QDs possess excellent photoacoustic (PA) performance and photothermal therapy (PTT) efficiency. After systemic administration, the Bi2 O2 Se QDs accumulate passively in tumors enabling efficient PA imaging of the entire tumors to facilitate imaging-guided PTT without obvious toxicity. Furthermore, the Bi2 O2 Se QDs which exhibit degradability in aqueous media not only have sufficient stability during in vivo circulation to perform the designed therapeutic functions, but also can be discharged harmlessly from the body afterward. The results reveal the great potential of Bi2 O2 Se QDs as a biodegradable multifunctional agent in medical applications.

Near-infrared light-triggered drug delivery system based on black phosphorus for in vivo bone regeneration.

A near-infrared (NIR) light-triggered drug delivery platform is produced by incorporating SrCl2 and BP nanosheets (BPs) into poly(lactic-co-glycolic acid) (PLGA) for bone regeneration. The fabricated BP-SrCl2/PLGA microspheres show efficient NIR absorption and photothermal effects due to the BPs. The NIR-triggered release behavior of Sr2+ by flawing the PLGA shells is investigated and the microspheres exhibit excellent cell viability and biodegradability. Implantation of the BP-SrCl2/PLGA microspheres into a rat femoral defect demonstrates good tissue compatibility and excellent bone regeneration capacity under NIR light irradiation. Our study indicates that local release of Sr2+ at optimal time periods controlled by NIR irradiation improves bone regeneration significantly and this NIR-triggered drug delivery system composed of BPs is suitable for therapies requiring precise control at specific time.

Biodegradable near-infrared-photoresponsive shape memory implants based on black phosphorus nanofillers.

In this paper, we propose a new shape memory polymer (SMP) composite with excellent near-infrared (NIR)-photoresponsive shape memory performance and biodegradability. The composite is fabricated by using piperazine-based polyurethane (PU) as thermo-responsive SMP incorporated with black-phosphorus (BP) sheets as NIR photothermal nanofillers. Under 808 nm light irradiation, the incorporated BP sheets with concentration of only 0.08 wt% enable rapid temperature increase over the glass temperature of PU and trigger the shape change of the composite with shape recovery rate of ∼100%. The in vitro and in vivo toxicity examinations demonstrate the good biocompatibility of the PU/BP composite, and it degrades naturally into non-toxic carbon dioxide and water from PU and non-toxic phosphate from BP. By implanting PU/BP columns into back subcutis and vagina of mice, they exhibit excellent shape memory activity to change their shape quickly under moderate 808 nm light irradiaiton. Such SMP composite enable the development of intelligent implantable devices, which can be easily controlled by the remote NIR light and degrade gradually after performing the designed functions in the body.

2D Material-Based Nanofibrous Membrane for Photothermal Cancer Therapy.

One of the clinical challenges facing photothermal cancer therapy is health risks imposed by the photothermal nanoagents in vivo. Herein, a photothermal therapy (PTT) platform composed of a 2D material-based nanofibrous membrane as the agent to deliver thermal energy to tumors under near-infrared (NIR) light irradiation is described. The photothermal membrane, which is fabricated by an electrospinning poly(l-lactic acid) (PLLA) nanofibrous membrane loaded with bismuth selenide (Bi2Se3) nanoplates, exhibits very high photothermal conversion efficiency and long-term stability. Cell experiments and hematological analyses demonstrate that the Bi2Se3/PLLA membranes have excellent biocompatibility and low toxicity. PTT experiments performed in vivo with the Bi2Se3/PLLA membrane covering the tumor and NIR irradiation produce local hyperthermia to ablate the tumor with high efficiency. Different from the traditional systematical and local injection techniques, this membrane-based PTT platform is promising in photothermal cancer therapy, especially suitable for the treatment of multiple solid tumors or skin cancers, and long-term prevention of cancer recurrence after surgery or PTT, while eliminating the health hazards of nanoagents.

Cell-borne 2D nanomaterials for efficient cancer targeting and photothermal therapy.

Two of the challenges for clinical implementation of nano-therapeutic strategies are optimization of tumor targeting and clearance of the nanoagents in vivo. Herein, a cell-mediated therapy by transporting 2D Bi2Se3 nanosheets within macrophage vehicles is described. The Bi2Se3 nanosheets with excellent near-infrared photothermal performance exhibit high macrophage uptake and negligible cytotoxicity thus facilitating the fabrication of Bi2Se3-laden-macrophages. Compared with bare Bi2Se3, the Bi2Se3-laden-macrophages after intravenous injection show prolonged blood circulation and can overcome the hypoxia-associated drug delivery barrier to target the tumor efficiently and dramatically enhance the efficiency of photothermal cancer therapy. The Bi2Se3-laden-macrophages possess good biocompatibility as demonstrated by the biochemical and histological analyses and furthermore, most of the materials are excreted from the body within 25 days. Our findings reveal a desirable system for highly efficient near-infrared photothermal cancer therapy.

Metabolizable Ultrathin Bi2 Se3 Nanosheets in Imaging-Guided Photothermal Therapy.

Poly(vinylpyrrolidone)-encapsulated Bi2 Se3 nanosheets with a thickness of 1.7 nm and diameter of 31.4 nm are prepared by a solution method. Possessing an extinction coefficient of 11.5 L g(-1) cm(-1) at 808 nm, the ultrathin Bi2 Se3 nanosheets boast a high photothermal conversion efficiency of 34.6% and excellent photoacoustic performance. After systemic administration, the Bi2 Se3 nanosheets with the proper size and surface properties accumulate passively in tumors enabling efficient photoacoustic imaging of the entire tumors to facilitate photothermal cancer therapy. In vivo biodistribution studies reveal that they are expelled from the body efficiently after 30 d. The ultrathin Bi2 Se3 nanosheets have large clinical potential as metabolizable near-infrared-triggered theranostic agents.

Ultrasmall Black Phosphorus Quantum Dots: Synthesis and Use as Photothermal Agents.

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.