Flower-like PEGylated MoS2 nanoflakes for near-infrared photothermal cancer therapy

Functionalized MoS2 Nanoflowers with Excellent Near-Infrared Photothermal Activities for Scavenging of Antibiotic Resistant Bacteria

Presently, antibiotic resistant bacteria (ARB) have been commonly found in environment, such as air, soil and lakes. Therefore, it is urgent and necessary to prepare antimicrobial agents with excellent anti-antibiotic resistant bacteria. In our research, poly-ethylene glycol functionalized molybdenum disulfide nanoflowers (PEG-MoS2 NFs) were synthesized via a one-step hydrothermal method. As-prepared PEG-MoS2 NFs displayed excellent photothermal conversion efficiency (30.6%) and photothermal stability. Under 808 nm NIR laser irradiation for 10 min, the inhibition rate of tetracycline-resistant Bacillus tropicalis and Stenotrophomonas malphilia reached more than 95% at the concentration of 50 μg/mL. More interestingly, the photothermal effect of PEG-MoS2 NFs could accelerate the oxidation of glutathione, resulting in the rapid death of bacteria. A functionalized PEG-MoS2 NFs photothermal anti-antibiotic resistant system was constructed successfully.

Photoluminescence and magnetism integrated multifunctional black phosphorus probes through controllable PO bond orbital hybridization

Biological probes with integrated photoluminescence and magnetism characteristics play a critical role in modern clinical diagnosis and surgical protocols combining fluorescence optical imaging (FOI) with magnetic resonance imaging (MRI) technology. However, traditional magnetic semiconductors can easily generate a spin splitting at the Fermi level and half-metallic electronic occupation, which will sharply reduce the radiation recombination efficiency of photogenerated carriers. To overcome this intrinsic contradiction, we propose a controllable oxidation strategy to introduce some particular PO bonds into black phosphorus nanosheets, in which the p orbital hybridization between P and O atoms not only provides some carrier recombination centers but also leads to a room-temperature spin polarization. As a result, the coexistence of photoluminescence and magnetism is realized in multifunctional black phosphorus probes with excellent biocompatibility. This work provides a new insight into integrating photoluminescence and magnetism together by intriguing atomic orbital hybridization.

Dendrimer-modified gold nanorods as a platform for combinational gene therapy and photothermal therapy of tumors

Background

The exploitation of novel nanomaterials combining diagnostic and therapeutic functionalities within one single nanoplatform is challenging for tumor theranostics.

Methods

We synthesized dendrimer-modified gold nanorods for combinational gene therapy and photothermal therapy (PTT) of colon cancer. Poly(amidoamine) dendrimers (PAMAM, G3) grafted gold nanorods were modified with GX1 peptide (a cyclic 7-mer peptide, CGNSNPKSC). The obtained Au NR@PAMAM-GX1 are proposed as a gene delivery vector to gene (FAM172A, regulates the proliferation and apoptosis of colon cancer cells) for the combination of photothermal therapy (PTT) and gene therapy of Colon cancer cells (HCT-8 cells). In addition, the CT imaging function of Au NR can provide imaging evidence for the diagnosis of colon cancer.

Results

The results display that Au NR@PAMAM-GX1 can specifically deliver FAM172A to cancer cells with excellent transfection efficiency. The HCT-8 cells treated with the Au NR@PAMAM-GX1/FAM172A under laser irradiation have a viability of 20.45%, which is much lower than the survival rate of other single-mode PTT treatment or single-mode gene therapy. Furthermore, animal experiment results confirm that Au NR@PAMAM-GX1/FAM172A complexes can achieve tumor thermal imaging, targeted CT imaging, PTT and gene therapy after tail vein injection.

Conclusion

Our findings demonstrate that the synthesized Au NR@PAMAM-GX1 offer a facile platform to exert antitumor and improve the diagnostic level of tumor.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-02105-3.

Synthesis of Molybdenum Sulfide/Tellurium Hetero-Composite by a Simple One-Pot Hydrothermal Technique for High-Performance Supercapacitor Electrode Material

It is necessary to investigate effective energy storage devices that can fulfill the requirements of short-term and long-term durable energy outputs. Here, we report a simple one-pot hydrothermal technique through which to fabricate the MoS2/Te nanocomposite to be used as an effective electrode material for high-performance supercapacitors. Comprehensive characterization of the as-fabricated nanomaterial was performed using FESEM, HRTEM, XRD, FTIR, XPS, etc., as well as electrochemical characterizations. The electrochemical characterization of the as-fabricated nanocomposite electrode material showed a high specific capacitance of 402.53 F g-1 from a galvanostatic charge-discharge (GCD) profile conducted at 1 A g-1 current density. The electrode material also showed significant rate performance with high cyclic stability reaching up to 92.30% under 4000 cycles of galvanostatic charge-discharge profile at a current density of 10 A g-1. The highly encouraging results obtained using this simple synthetic approach demonstrate that the hetero-structured nanocomposite of MoS2/Te electrode material could serve as a promising composite to use in effective supercapacitors or energy storage devices.

Advances in Cancer Therapeutics: Conventional Thermal Therapy to Nanotechnology-Based Photothermal Therapy

In this review, advancement in cancer therapy that shows a transition from conventional thermal therapies to laser-based photothermal therapies is discussed. Laser-based photothermal therapies are gaining popularity in cancer therapeutics due to their overall outcomes. In photothermal therapy, light is converted into heat to destruct the various types of cancerous growth. The role of nanoparticles as a photothermal agent is emphasized in this review article. Magnetic, as well as non-magnetic, nanoparticles have been effectively used in the photothermal-based cancer therapies. The discussion includes a critical appraisal of in vitro and in vivo, as well as the latest clinical studies completed in this area. Plausible evidence suggests that photothermal therapy is a promising avenue in the treatment of cancer.

Thermal Treatment of Polyvinyl Alcohol for Coupling MoS2 and TiO2 Nanotube Arrays toward Enhancing Photoelectrochemical Water Splitting Performance

Solar-driven photoelectrochemical (PEC) water splitting, using semiconductor photoelectrodes, is considered a promising renewable energy source and solution for environmental sustainability. Herein, we report polyvinyl alcohol (PVA) as a binder material for combining MoS2 and TiO2 nanotube arrays (TNAs) to improve PEC water splitting ability. By a thermal treatment process, the formation of the π conjunction in the PVA structure enhanced the PEC performance of MoS2/TNAs, exhibiting linear sweeps in an anodic direction with the current density over 65 μA/cm2 at 0 V vs. Ag/AgCl. Besides, the photoresponse ability of MoS2/TNAs is approximately 6-fold more significant than that of individual TNAs. Moreover, a Tafel slope of 140.6 mV/decade has been obtained for the oxygen evolution reaction (OER) of MoS2/TNAs materials.

Hydrothermal green synthesis of MoS2 nanosheets for pollution abatement and antifungal applications

In this study, we report a green synthesis of MoS₂ nanosheets (NSs) using a facile hydrothermal technique in the presence of l-cysteine. l-Cysteine can serve as a greener source of sulfur as well as a capping agent to help the growth of MoS₂ nanosheets. The prepared materials were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), electron transmission microscopy (TEM), X-ray photoelectron microscopy (XPS), and Brunauer, Emmett, and Teller (BET) analysis. The results showed that MoS₂ NSs are of high crystallinity with a lattice spacing of 0.61 nm. The optical bandgap of MoS₂ NSs nanosheets prepared using l-cysteine as a source of sulfur was found to be 1.79 eV. The photocatalytic degradation of MoS₂ NSs towards methylene orange (MO) and rhodamine blue (RB) dyes under sunlight was found to be promising for practical applications. The fast kinetics of degradation of MO and RhB was observed over a wide range of pH range. Moreover, MoS₂ NSs showed excellent antifungal activities against Trichophyton mentagrophytes and Penicillium chrysogenum fungus.

Transition metal dichalcogenide (TMDs) electrodes for supercapacitors: a comprehensive review

As globally, the main focus of the researchers is to develop novel electrode materials that exhibit high energy and power density for efficient performance energy storage devices. This review covers the up-to-date progress achieved in transition metal dichalcogenides (TMDs) (e.g. MoS₂, WS₂, MoSe_2,and WSe₂) as electrode material for supercapacitors (SCs). The TMDs have remarkable properties like large surface area, high electrical conductivity with variable oxidation states. These properties enable the TMDs as the most promising candidates to store electrical energy via hybrid charge storage mechanisms. Consequently, this review article provides a detailed study of TMDs structure, properties, and evolution. The characteristics technique and electrochemical performances of all the efficient TMDs are highlighted meticulously. In brief, the present review article shines a light on the structural and electrochemical properties of TMD electrodes. Furthermore, the latest fabricated TMDs based symmetric/asymmetric SCs have also been reported.

Voltammetric detection of vitamin D employing Au-MoS2 hybrid as immunosensing platform

A voltammetric immunosensor based on molybdenum sulphide (MoS₂) and gold nanoparticles (Au NPs) for the determination of 25-hydroxy vitamin D₃ (25(OH)D₃) is reported. Anti-vit D (Ab-25(OH)D₃) was immobilized onto the cysteamine-modified MoS₂ and Au NPs which were deposited onto a fluoride tin oxide (FTO) electrode (Ab/Cys/Au/MoS₂/FTO). The MoS₂ sheets were prepared by hydrothermal method followed by an in situ growth of Au film onto the MoS₂/FTO surface. Self-assembled monolayer (SAM) of cysteamine was synthesized onto the Au/MoS₂/FTO which acts as a linker to covalently bind Ab-25(OH)D₃. The Ab-25(OH)D₃-immobilized Cys/Au/MoS₂/FTO was used to detect 25(OH)D₃ using differential pulse voltammetry. The electrochemical system provided an anodic peak current at a potential of +0.21 V vs. Ag/AgCl (satd. KCl) of ferricyanide/ferrocyanide redox couple. The detection principle relies on the inhibition of electron transfer at the electrode surface owing to the hindrance caused by the formation of immune complex between Ab-25(OH)D₃ and 25(OH)D₃. The immunosensor shows linear response from 1 pg mL^-1 to 100 ng mL^-1 25(OH)D₃ and a sensitivity of 189 μA [log (pg mL^-1)]^-1 cm^-2 along with a low limit of detection (LOD) of 0.38 pg mL^-1. The immunosensor is highly selective towards 25(OH)D₃ and presented a long shelf life of 28 days. Also, the immunosensor exhibits satisfactory performance towards spiked human serum samples with recovery between 95.1 and 102% (RSD 1.15-3.22%).

Light-Triggered In Situ Gelation of Hydrogels using 2D Molybdenum Disulfide (MoS2 ) Nanoassemblies as Crosslink Epicenter

Light-responsive biomaterials are an emerging class of materials used for developing noninvasive, noncontact, precise, and controllable biomedical devices. Long-wavelength near-infrared (NIR) radiation is an attractive light source for in situ gelation due to its higher penetration depth and minimum side effects. The conventional approach to obtain crosslinked biomaterials relies heavily on the use of a photoinitiator by generating reactive species when exposed to short-wavelength radiation, which is detrimental to surrounding cells and tissue. Here, a new class of NIR-triggered in situ gelation system based on defect-rich 2D molybdenum disulfide (MoS2 ) nanoassemblies and thiol-functionalized thermoresponsive polymer in the absence of a photoinitiator is introduced. Exposure to NIR radiation activates the dynamic polymer-nanomaterials interactions by leveraging the photothermal characteristics of MoS2 and intrinsic phase transition ability of the thermoresponsive polymer. Specifically, upon NIR exposure, MoS2 acts as a crosslink epicenter by connecting with multiple polymeric chains via defect-driven click chemistry. As a proof-of-concept, the utility of NIR-triggered in situ gelation is demonstrated in vitro and in vivo. Additionally, the crosslinked gel exhibits the potential for NIR light-responsive release of encapsulated therapeutics. These light-responsive biomaterials have strong potential for a range of biomedical applications, including artificial muscle, smart actuators, 3D/4D printing, regenerative medicine, and therapeutic delivery.

Progress in the therapeutic applications of polymer-decorated black phosphorus and black phosphorus analog nanomaterials in biomedicine

Wonderful black phosphorus (BP) and some BP analogs (BPAs) have been increasingly studied for their biomedical applications owing to their fascinating properties and biodegradability, but opportunities and challenges have always coexisted in their study. Poor stability upon exposure to the natural environment is the major obstacle hampering their in vivo applications. BP/polymer and BPAs/polymer nanocomposites can not only efficiently prevent their oxidation and aggregation but also exhibit "biological activity" due to synergistic effects. In this review, we briefly describe the synthesis methods and stability strategies of BP/polymer and BPAs/polymer. Then, advances pertaining to their exciting therapeutic applications in various fields are systematically introduced, such as cancer therapy (phototherapy, drug delivery, and synergistic immunotherapy), bone regeneration, and neurogenesis. Some challenges for future clinical trials and possible directions for further study are finally discussed.

Synergic Effect of Novel WS2 Carriers Holding Spherical Cobalt Ferrite @cubic Fe3O4 (WS2/s-CoFe2O4@c-Fe3O4) Nanocomposites in Magnetic Resonance Imaging and Photothermal Therapy for Ocular Treatments and Investigation of Corneal Endothelial Cell Migration

The design of novel materials to use simultaneously in an ocular system for driven therapeutics and wound healing is still challenging. Here, we produced nanocomposites of tungsten disulfide carriers with spherical cobalt ferrite nanoparticles (NPs) as core inside a cubic iron oxide NPs shell (WS2/s-CoFe2O4@c-Fe3O4). Transmission electron microscopy (TEM) confirmed that 10 nm s-CoFe2O4@c-Fe3O4 NPs were attached on the WS2 sheet surfaces. The cytotoxicity of the WS2 sheets and nanocomposites were evaluated on bovine cornea endothelial cells (BCECs) using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay for a duration of three days. The MTT assay results showed low toxicity of the WS2 sheets on BCECs by 67% cell viability at 100 μg/mL in 24 h, while the nanocomposites show 50% cell viability in the same conditions. The magnetic resonance imaging (MRI) of nanocomposites revealed the excellent T2-weighted imaging with an r2 contrast of 108 mM-1 S-1. The in vitro photothermal therapy based on WS2 sheets and WS2/s-CoFe2O4 @c-Fe3O4 nanocomposites using 808 nm laser showed that the maximum thermal energy dispatched in medium at different applied power densities (1200 mw, 1800, 2200, 2600 mW) was for 0.1 mg/mL of the sample solution. The migration assay of BCECs showed that the wound healing was approximately 20% slower for the cell exposed by nanocomposites compared with the control (no exposed BCECs). We believe that WS2/s-CoFe2O4@c-Fe3O4 nanocomposites have a synergic effect as photothermal therapy agents for eye diseases and could be a target in an ocular system using MRI.

Two-dimensional materials in biomedical, biosensing and sensing applications

Two-dimensional (2D) materials are at the forefront of materials research. Here we overview their applications beyond graphene, such as transition metal dichalcogenides, monoelemental Xenes (including phosphorene and bismuthene), carbon nitrides, boron nitrides along with transition metal carbides and nitrides (MXenes). We discuss their usage in various biomedical and environmental monitoring applications, from biosensors to therapeutic treatment agents, their toxicity and their utility in chemical sensing. We highlight how a specific chemical, physical and optical property of 2D materials can influence the performance of bio/sensing, improve drug delivery and photo/thermal therapy as well as affect their toxicity. Such properties are determined by crystal phases electrical conductivity, degree of exfoliation, surface functionalization, strong photoluminescence, strong optical absorption in the near-infrared range and high photothermal conversion efficiency. This review conveys the great future of all the families of 2D materials, especially with the expanding 2D materials' landscape as new materials emerge such as germanene and silicene.

Co-FeS2/CoS2 Heterostructured Nanomaterials for pH Sensing

Biosensors are widely used in production and life, and can be used in medicine, industrial production, and scientific research. Among them, the detection of pH has always received extensive attention. In this study, we demonstrate the use of a one-step hydrothermal method to prepare Co-FeS2/CoS2 nanomaterials as pH sensor (pH vs. overpotential) for the first time. The proposed pH sensor exhibits outstanding performance in KOH solutions via electrochemical methods with good stability. Overall, the results of this study not only add to the non-noble transition metal electrocatalysis research, but also identify important sensing characteristics for electrocatalysts.

Facile synthesis of biocompatible L-cysteine-modified MoS2 nanospheres with high photothermal conversion efficiency for photothermal therapy of tumor

Photothermal therapy (PTT) can take advantage of the photothermal effects of photothermal agents to acquire the energy from laser irradiation and convert it into heat. This can intensively elevate the temperature of the surrounding environment to directly destroy the cancer cells. It is expected that PAs with strong absorption in near infrared (NIR) range might possess the ideal tissue-transparent feature and minimal damage to surrounding healthy tissues, beneficial to the practical application. Herein, well-dispersed L-cysteine modified MoS₂ (MoS₂-Cys) nanospheres with the average diameter of about 422 nm and strong NIR adsorption were successfully synthesized through a facile method. The as-prepared MoS₂-Cys nanospheres are composed of nanosheets with the average thickness of about 13.7 nm. The photothermal conversion efficiency of the as-prepared MoS₂-Cys nanospheres with the very low concentration of 50 μg/mL was determined to be 35% when exposed to 808 NIR laser at the power density of 0.8 W/cm², much higher than those of the previous reports with same dose and power density. MoS₂-Cys nanospheres possessed the good photothermal ablation effect to significantly inhibit the growth of tumor in vivo. Furthermore, MoS₂-Cys nanospheres did not exhibit detectable side effects, suggesting their good in vitro and in vivo biocompatibility.

The emergence of red fluorescence from two-dimensional nitrogenated-stanene oxide nanosheets

The instigation of fluorescence in 2D metal oxide nanosheets is a daunting task to achieve. In the present work, we have synthesized bright red fluorescent stanene oxide (rSt_NS nanosheets) using an exceptionally simple method. Tin(ii) chloride added to a complex solvent (non-aqueous solution) of acetone and acetonitrile was sonicated and incubated at ambient temperature for ∼six days. After three days (72 h), the solution turned light yellow with bright red fluorescence; this is possible due to interactions between Sn and nitrogen atoms in a nanoscale environment. The emission from rSt_NS nanosheets (λ_ex = 370 nm) covered a broad range of the optical spectrum (with a prominent peak at 590 nm). Interestingly, after day five, the colour of the solution became darker, and the colour of fluorescence changed from red to green (gSt_NS nanosheets).

Photothermal Transduction Efficiencies of Plasmonic Group 4 Metal Nitride Nanocrystals

The photothermal transduction efficiencies of group 4 metal nitrides, TiN, ZrN, and HfN, at λ = 850 nm are reported, and the performance of these materials is compared to an Au nanorod benchmark. Transition metal nitride nanocrystals with an average diameter of ∼15 nm were prepared using a solid-state metathesis reaction. HfN exhibited the highest photothermal transduction efficiency of 65%, followed by ZrN (58%) and TiN (49%), which were all higher than those of the commercially purchased Au nanorods (43%). Computational studies performed using a finite element method showed HfN and Au to have the lowest and highest scattering cross section, respectively, which could be a contributing factor to the efficiency trends observed. Furthermore, the changes in temperature as a function of illumination intensity and solution concentration, as well as the cycling stability of the metal nitride solutions, were studied in detail.

Coordination-Driven Hierarchical Assembly of Hybrid Nanostructures Based on 2D Materials

2D materials have received tremendous scientific and engineering interests due to their remarkable properties and broad-ranging applications such as energy storage and conversion, catalysis, biomedicine, electronics, and so forth. To further enhance their performance and endow them with new functions, 2D materials are proposed to hybridize with other nanostructured building blocks, resulting in hybrid nanostructures with various morphologies and structures. The properties and functions of these hybrid nanostructures depend strongly on the interfacial interactions between 2D materials and other building blocks. Covalent and coordination bonds are two strong interactions that hold high potential in constructing these robust hybrid nanostructures based on 2D materials. However, most 2D materials are chemically inert, posing problems for the covalent assembly with other building blocks. There are usually coordination atoms in most of 2D materials and their derivatives, thus coordination interaction as a strong interfacial interaction has attracted much attention. In this review, recent progress on the coordination-driven hierarchical assembly based on 2D materials is summarized, focusing on the synthesis approaches, various architectures, and structure-property relationship. Furthermore, insights into the present challenges and future research directions are also presented.

Near-Infrared Light-Switched MoS2 Nanoflakes@Gelatin Bioplatform for Capture, Detection, and Nondestructive Release of Circulating Tumor Cells

The integrative bioplatform for capture, detection and release of circulating tumor cells (CTCs) is of great significance in clinical diagnosis and biomedical research. To fulfill this demand, we introduced a near-infrared (NIR) light-switched bioplatform for efficient isolation and downstream analysis of CTCs. The platform was created by first modifying the PEG-MoS₂ nanoflakes (NFs)@gelatin nanocomposite on the ITO surface, and then introducing the MUC1 aptamer as a specific recognition element via coupling reaction between aptamer and gelatin to achieve the specific capture for CTCs. Subsequently, the captured cells are released under a NIR light irradiation (808 nm) by using MoS₂ NFs as the NIR-regulated control element. Significantly, this platform could capture and release of CTCs with an excellent capture/release efficiency of 89.5% and 92.5%, respectively. Furthermore, the electrochemical bioplatform exhibited a wide linear range for the detection of CTCs from 50 to 1 × 10⁶ cells mL^-1 with a detection limit of 15 cells mL^-1. After 5 days of reculture, the released cells still maintain good cell shape and proliferation capacity. Moreover, the bioplatfrom is a simple, versatile, and universal system for the recognition, capture, release, and detection of different types of CTCs. Therefore, this bioplatform shows potential applications on the early diagnosis of cancers.

Synthesis of a Clay-Based Nanoagent for Photonanomedicine

Photo-induced cancer therapies, mainly including photothermal therapy (PTT) and photodynamic therapy (PDT), have attracted numerous attentions owing to the high selectivity, convenience, and few side effects. However, single PTT usually requires high laser power density, and single PDT usually needs a high photosensitizer dosage. Herein, a kind of composite nanocarrier based on clay (laponite)-polypyrrole (LP) nanodisks was synthesized via the in situ polymerization of pyrrole in the interlayer space of laponite. LP composite nanodisks were then coated with polyvinylpyrrolidone (PVP) to form the LP-PVP (LPP) composite nanodisks which show an excellent colloidal stability and in vitro and in vivo biocompatibility. The interlayer space of LPP can be further used for the loading of Chlorin e6 (Ce6), with an ultrahigh loading capacity of about 89.2%. Furthermore, the LPP nanocarrier can enhance the PDT effect of Ce6 under the irradiation of a 660 nm laser, through enhancing its solubility and cellular uptake amount. Besides, it was found that LPP nanodisks exhibit a more outstanding photothermal performance under a 980 nm near-infrared laser (NIR) than a 808 nm NIR laser, with the photothermal conversion efficiency of 45.7 and 27.7%, respectively. The in vitro and in vivo tumor therapy results evidently confirm that the Ce6-loaded LPP nanodisks have a combined tumor PTT and PDT effect, which can significantly suppress the tumor malignant proliferation.

The synthesis of two-dimensional Bi2Te3@SiO2core–shell nanosheets for fluorescence/photoacoustic/infrared (FL/PA/IR) tri-modal imaging-guided photothermal/photodynamic combination therapy

Surface activated Bi₂Te₃nanosheets (NSs) conjugated with chlorin e6 (Ce6) were developed for high-performance tumor theranostics.

Overview of the application of inorganic nanomaterials in cancer photothermal therapy

Cancer photothermal therapy (PTT) has captured the attention of researchers worldwide due to its localized and trigger-activated therapeutic effect.

A bioconjugated MoS2 based nanoplatform with increased binding efficiency to cancer cells

Preparation and study of a MoS₂ nanosheet based nanoplatform for a cancer detection and treatment system equipped with an antibody–antigen based recognition element.

Mesoporous carbon‑manganese nanocomposite for multiple imaging guided oxygen-elevated synergetic therapy

Despite of the extensive application of photodynamic therapy (PDT)nowadays, several restrictions have emerged such as hydrophobility, undesired phototoxicity and low selectivity of photosensitizer as well as the hypoxic tumor microenvironment. To address these challenges, a multifunctional mesoporous carbon‑manganese nanocomposite (MC-MnO₂) is developed to load Chlorin e6 (Ce6) with a high loading capacity. The MC-MnO₂ can prevent Ce6 from being activated by the sunlight to reduce unintentional phototoxicity significantly and realize the hypoxia relief via reacting with the H₂O₂ overexpressed in tumor tissue, meanwhile, the reduced product Mn²⁺ ion could act as a T1/T2-weighted MRI contrast. Based on the broad absorption of MC-MnO₂ within the range of NIR, the nanoparticle has the potential for serving as a photothermal agent and photoacoustic imaging (PAI) agent. The PEG and iRGD are further decorated on MC-MnO₂ (iPMC-MnO₂) to improve the biocompatibility, targeting and penetration of the nanoparticle. Taking full advantage of the good photothermal effect of iPMC-MnO₂, the photothermal therapy (PTT) and enhanced PDT are subtly integrated into one system, developing an intelligent multimodal diagnostic and therapeutic nanoplatform and realizing our "one nanoparticle fits all" dream.

Synergistic photothermal/photodynamic suppression of prostatic carcinoma by targeted biodegradable MnO2 nanosheets

The biodegradability and clearance of metal-based nanomaterials have been questioned worldwide, which have greatly limited their clinical translation. Herein, ultrathin manganese dioxide (MnO2) nanosheets with broad near-infrared (NIR) absorption and pH-dependent degradation properties were prepared. After being modified with polyethylene glycol-cyclic arginine-glycineaspartic acid tripeptide (PEG-cRGD), the MnO2 nanosheets were then used as photothermal agent and nanocarrier to encapsulate chlorin e6 (Ce6) for targeted photothermal (PTT) and photodynamic (PDT) of cancer. As expected, the MnO2-PEG-cRGD nanosheets show high Ce6 loading capacity (351 mg/g), superb photothermal conversion performance (37.2%) and excellent colloidal stability. These nanosheets also exhibit pH-dependent and NIR-induced Ce6 release. Furthermore, the MnO2 nanosheets can be degraded by reacting with hydrogen peroxide in the acidic microenvironment, which are able to elevate the oxygen concentration in situ and thus reverses the tumor hypoxia. Thanks to these favorable properties and the cRGD-mediated tumor-targeted ability, the fabricated MnO2-PEG-cRGD/Ce6 nanocomposites can be effectively up taken by alpha-v beta-3 (αvβ3) integrin over-expressed prostatic carcinoma PC3 cells and achieve favorable therapeutic outcomes under a single 660 nm NIR laser, which is also verified by in vitro studies. The biodegradable MnO2-PEG-cRGD/Ce6 nanosheets developed in this work can be a promising nanoplatform for synergetic PTT/PDT cancer therapy.

Electrocatalytic synthesis of black tin oxide nanomaterial as photothermal agent for cancer therapy

Photothermal therapy (PTT) is among the popular approach for treating solid tumours. The rapid killing of cancer cells under the influence of infrared radiation by a rapid increase in the temperature of the remote area now demands external agents with high photothermal transduction efficiency (PTE). Despite their improved PTE, black nanomaterials such as black phosphorus and titanium oxide are unable to meet the challenges in the physiological conditions. To address this major concern, we have developed black tin oxide (bSnO) with enhanced capabilities to respond in the physiological milieu. To make the synthesis cost-effective and eco-friendly, we have used electrochemical oxidation at 5 V and 100 mA to achieve ∼15 nm nanoparticle of bSnO. The as-synthesized bSnO exhibited high NIR absorption as well as high photothermal transduction efficiency. To circumvent the low aqueous solubility and photostability, bSnO was functionalized with polyethyleneimine (PEI). Upon exposure to 808 nm laser for ∼8-10 min, the temperature of the bSnO@PEI solution reached ∼58.5 °C. PTE of bSnO@PEI was calculated to be 51.2%. Owing to its high biological compatibility, tin offers relatively better stability when exposed to cancer cells in vitro and in vivo. In comparison to other black nanomaterials, bSnO@PEI was found to exhibit better response under NIR irradiance for non-invasive photothermal therapy of cancer.

Exploiting Single Atom Iron Centers in a Porphyrin-like MOF for Efficient Cancer Phototherapy

In recent years, single-atom catalysts (SACs) have attracted enormous attention due their effectiveness in promoting a variety of catalytic reactions. However, the ability of SACs to enhance cancer phototherapies has received little attention to date. Herein, we synthesized a metal organic framework (MOF) rich in porphyrin-like single atom Fe(III) centers (denoted herein as porphyrin-MOF or P-MOF) and then evaluated the performance of the P-MOF for cancer treatment by photodynamic therapy (PDT) and photothermal therapy (PTT) under NIR (808 nm) irradiation, as well as photoacoustic imaging (PAI) of tumors. On acccount of the abundance of single atom Fe(III) centers, the P-MOF material demonstrated excellent performance for modulation of the hypoxic tumor microenvironment of Hela cell tumors in mice, while also demonstrating good properties as a photoacoustic imaging (PAI) agent. Density functional theory (DFT) calculations were used to elucidate the superior performance of P-MOF in these applications relative to Fe₂O₃ (a Fe(III) reference compound). The calculations revealed that the narrow band gap energy of P-MOF (1.31 eV) enabled strong absorption of NIR photons, thereby inducing nonradiative transitions that converted incident light into heat to promote PTT. Further, a facile change of the spin state of the single atom Fe(III) centers in P-MOF under NIR irradiation transformed coordinated triplet oxygen (³O₂) to singlet oxygen (¹O₂), benefiting PDT. This work demonstrates the great future potential of both SACs and MOFs as multifunctional agents for cancer treatment and tumor imaging.

Antimonene Nanoflakes: Extraordinary Photoacoustic Performance for High-Contrast Imaging of Small Volume Tumors

Photoacoustic imaging (PAI) has evolved to a stage that high-performance exogeneous contrast agents are urgently needed for imminent biomedical and clinical applications. Given that a material meets the basic criteria of efficient photoacoustic conversion, high biocompatibility, and fast excretion, great effort has been devoted to evaluating various materials for developing advantageous contrast agents to explore the full potentials of PAI. One focus is through modification of the current agents to boost their PA performance; whilst the other focus is to develop novel agents. Antimonene (AM) has emerged as a promising candidate for next generation of electronics among 2D materials due to its outstanding properties. Herein, it is reported that liquid-phase exfoliated antimonene exhibits extraordinary photoacoustic performance, which is not only more advantageous than other 2D materials, such as black phosphorus, graphene oxide, and transition metal dichalcogenides, but also superior to the commonly used PA contrast agents, such as ICG and gold nanorods. An insight analysis reveals that the unique thermal property of AM, including intrinsic low thermal conductivity and the morphology-related high interfacial thermal conductivity, might interpret the high photothermal conversion efficiency, and thus the excellent photoacoustic performance. The prodigious performance allows sensitive monitoring of intracellular events and high-quality in vivo tumor imaging.

Bismuth embedded silica nanoparticles loaded with autophagy suppressant to promote photothermal therapy

An unpredicted side effect of photothermal therapy (PTT) is agitated by hyperthermia which results in damage to healthy tissue. Developing PTT platforms, enabling effective tumor ablation under mild irradiation conditions, is of wide interest, but challenging. Here, we investigated bismuth crystals embedded silica (Bi@SiO₂) nanoparticles, loaded with an autophagy inhibitor (chloroquine, CQ). It was found that SiO₂ effectively prevented the oxidization of Bi nanocrystals in the physiological environment and could serve as a scatter layer to improve NIR absorption, enabling a high photothermal conversion efficiency (~43%) and excellent photostability. Furthermore, the findings indicated that CQ molecules, delivered intracellularly by the particles, significantly weakened the degradation of autolysosomes by lysosome within the tumor cells, thus inducing suppression effect to autophagy and resistance to photothermia. Both in vitro and in vivo anti-tumor effects were consequently promoted owing to the combined effects enabled by Bi@SiO₂-CQ nanoparticles under mild NIR irradiation conditions. This study demonstrates a potential new PTT platform with superior therapeutic efficacy.

Nanobiomaterials: from 0D to 3D for tumor therapy and tissue regeneration

Nanobiomaterials have attracted tremendous attention in the biomedical field. Especially in the past few years, a large number of low dimensional nanobiomaterials, including 0D nanostructures, 1D nanotubes and 2D nanosheets, were employed for tumor therapy due to their optically triggered tumor therapy effects and drug loading capacities. However, these low dimensional nanobiomaterials cannot support cell adhesion and possess poor tissue regeneration ability, thus they are not suitable for application in regenerative medicine. Three dimensional (3D) nanofiber scaffolds have attracted extensive attention in tissue regeneration, including bone, skin, nerve and cardiac tissues, due to their similar extracellular matrix structures. Additionally, many 3D scaffolds displayed bone and cartilage regeneration abilities. Therefore, to obtain materials with both tumor therapy and tissue regeneration abilities, it is meaningful and necessary to develop 3D nanobiomaterials with multifunctions. In this review, we systematically review the research progress of nanobiomaterials with varied dimensional structures including 0D, 1D, 2D and 3D, as well as evolutional functions from single tumor therapy to simultaneous tumor therapy and tissue regeneration. This review may pave the way for developing an interdisciplinary research of nanobiomaterials in combination of tumor therapy and regenerative medicine.

Silica-Coated TiN Particles for Killing Cancer Cells

Photothermal therapy (PTT) using plasmonic nanoparticles for cancer treatment is on the verge of clinical application. Titanium nitride (TiN) nanoparticles offer a promising alternative to commonly used gold-based systems at a fraction of the costs. Little is known, however, about the relationship between TiN particle characteristics and their optical properties in colloidal systems. Here, TiN nanoparticles with closely controlled characteristics are prepared by nitridation of TiO₂, and their use as PTT agents is explored. Emphasis is placed on the particle surface and core oxygen content, which dominate the TiN optical properties. Colloidal suspensions were studied under UV-vis and near-infrared (NIR) laser irradiation and correlated to particle characteristics. High nitridation temperatures and long residence times lead to increased NIR light absorption. Too high nitridation temperatures, however, lead to particle aggregation that deteriorated their optical properties. This was overcome with SiO₂ coating of TiO₂ nanoparticles prior to nitridation: the resulting SiO₂-coated TiN particles exhibited increased plasmonic performance compared to bare TiN, which is attributed to reduced plasmonic coupling effects. The optimized SiO₂-coated TiN had a photothermal efficiency of 58.5% and mass extinction coefficient of 31.6 L g^-1 cm^-1, outperforming commercial gold nanoshells that are used in clinical trials. The potential of SiO₂-coated TiN for photothermal therapy was demonstrated by controllably killing HeLa cells in vitro.

Rod-shape MSN@MoS2 Nanoplatform for FL/MSOT/CT Imaging-Guided Photothermal and Photodynamic Therapy

Rod-shape nanoplatform have received tremendous attention owing to their enhanced ability for cell internalization and high capacity for drug loading. MoS2, widely used in electronic devices, electrocatalysis, sensor and energy-storage, has been studied as photothermal agents over the years. However, the efficacy of rod-shape MoS2 based photothermal agents for photothermal therapy has not been studied before. Here, a near-infrared (NIR) light-absorbing MoS2 nanosheets coated mesoporous silica nanorods with human serum albumin (HSA) modifying and Ce6 loading (MSNR@MoS2-HSA/Ce6) were constructed for combined photothermal and photodynamic therapy. Methods: The near-infrared (NIR) light was used to trigger the synergistic anti-tumor therapy. In addition, breast cancer cell line was applied to evaluate the in vitro anti-tumor activity. The multi-modal imaging capacity and tumor-killing efficiency of the designed nanocomposites in vivo was also demonstrated with the 4T1 tumor-bearing mouse model. Results: These nanocomposites could not only perform NIR light triggered photodynamic therapy (PDT) and photothermal therapy (PTT), but also achieve in vivo fluorescence (FL) /multispectral optical tomography (MSOT)/X-ray computed tomography (CT) triple-model bioimaging. What's more, the rod-shape nanoplatform could be endowed with better anti-tumor ability based on the EPR effect and HSA-mediated active tumor targeting. At the same time, the hyperthermia generated by MoS2 could synergistically improve the PDT effect with the acceleration of the blood flow, leading to the increase of the oxygen level in tumor tissue. Conclusion: MSNR@MoS2-HSA/Ce6 proves to be a promising multi-functional nanoplatform for effective treatment of tumor.

Peptide-Drug Conjugate-Based Nanocombination Actualizes Breast Cancer Treatment by Maytansinoid and Photothermia with the Assistance of Fluorescent and Photoacoustic Images

To develop a highly efficient strategy against tumors, here, a nanocombination (PDC/P@HCuS) was designed and constructed to actualize chemo-phototherapy with the assistance of fluorescence (FL) and photoacoustic (PA) images. First, a type of organic-inorganic hybrid nanosystem (P@HCuS) was engineered by coupling the fluorescence-labeled amphiphilic fPEDC copolymer on the surface of hollow mesoporous copper sulfide nanoparticle (HCuS), in which HCuS was used as a photothermal and PA agent; fPEDC as a stabilizer, chromophore, and redox/pH-sensitive gatekeeper; and both of them as drug carriers. Then, a peptide-drug conjugate (cRGD-SMCC-DM1, PDC), as a molecular targeted maytansinoid, was loaded inside of P@HCuS to form PDC/P@HCuS. Next, the PDC/P@HCuS was investigated carefully with or without near-infrared (NIR) laser irradiation. In vitro, the nanocombination exhibited stimuli-responsive drug release, obvious cellular uptake, strong cytotoxicity to tumor cells, significant impact on cell cycle, and cytoskeleton and cellular proteomics as well as evident permeability into the tumor sphere, most of which could be boosted by NIR laser irradiation. In vivo, the nanocombinaiton exerted good FL/PA imaging features and photothermal efficiency, achieved the best antitumor efficacy in the presence of NIR laser irradiation, and showed excellent biosafety. Together, it demonstrated that the PDC/P@HCuS, representing a chemo-phototherapy based on a nanocombination associated with peptide-drug conjugate, could achieve the highly efficient antitumor effect.

Low Power Single Laser Activated Synergistic Cancer Phototherapy Using Photosensitizer Functionalized Dual Plasmonic Photothermal Nanoagents

Combination therapy, especially photodynamic/photothermal therapy (PDT/PTT), has shown promising applications in cancer therapy. However, sequential irradiation by two different laser sources and even the utilization of single high-power laser to induce either combined PDT/PTT or individual PTT will be subjected to prolonged treatment time, complicated treatment process, and potential skin burns. Thus, low power single laser activatable combined PDT/PTT is still a formidable challenge. Herein, we propose an effective strategy to achieve synergistic cancer phototherapy under low power single laser irradiation for short duration. By taking advantage of dual plasmonic PTT nanoagents (AuNRs/MoS₂), a significant increase in temperature up to 60 °C with an overall photothermal conversion efficiency (PCE) of 68.8% was achieved within 5 min under very low power (0.2 W/cm²) NIR laser irradiation. The enhanced PCE and PTT performance is attributed to the synergistic plasmonic PTT effect (PPTT) of dual plasmonic nanoagents, promoting simultaneous release (85%) of electrostatically bonded indocyanine green (ICG) to induce PDT effects, offering simultaneous PDT/synergistic PPTT. Both in vitro and in vivo investigations reveal complete cell/tumor eradication, implying that simultaneous PDT/synergistic PPTT effects induced by AuNRs/MoS₂-ICG are much superior over individual PDT or synergistic PPTT. Notably, synergistic PPTT induced by dual plasmonic nanoagents also demonstrates higher in vivo antitumor efficacy than either individual PDT or PTT agents. Taken together, under single laser activation with low power density, the proposed strategy of simultaneous PDT/synergistic PPTT effectively reduces the treatment time, achieves high therapeutic index, and offers safe treatment option, which may serve as a platform to develop safer and clinically translatable approaches for accelerating cancer therapeutics.

Ce6-Modified Carbon Dots for Multimodal-Imaging-Guided and Single-NIR-Laser-Triggered Photothermal/Photodynamic Synergistic Cancer Therapy by Reduced Irradiation Power

Photomediated cancer therapy, mainly including photothermal (PT) therapy (PTT) and photodynamic therapy (PDT), has attracted tremendous attention in recent years thanks to its noninvasive and stimuli-responsive features. The single mode of PTT or PDT, however, has obvious drawbacks, either requiring high-power laser irradiation to generate enough heat or only providing limited efficacy due to the hypoxia nature inside tumors. In addition, the reported synergistic PTT/PDT generally utilized two excitation sources to separately activate PTT and PDT, and the problem of high-power laser irradiation for PTT was still not well solved. Herein, a new concept, loading a small amount of photosensitizers onto a PTT agent (both of them can be triggered by a single-near-infrared (NIR) laser), was proposed to evade the shortcomings of PTT and PDT. To validate this idea, minute quantities of photosensitizer chlorin e6 (Ce6) (0.56% of mass) were anchored onto amino-rich red emissive carbon dots (RCDs) that possess superior photothermal (PT) character under 671 nm NIR laser (PT conversion efficiency to be 46%), and meanwhile the PDT of Ce6 can be activated by this laser irradiation as well. The findings demonstrate that Ce6-modified RCDs (named Ce6-RCDs) offer much higher cancer therapy efficacy under a reduced laser power density (i.e., 0.50 W cm^-2 at 671 nm) in vitro and in vivo than the equivalent RCDs or Ce6 under the same irradiation conditions. Besides, the Ce6-RCDs also exhibit multimodal imaging capabilities (i.e., fluorescence (FL), photoacoustic (PA), and PT), which can be employed for guidance of the phototherapy process. This study suggests not only a strategy to enhance cancer phototherapy efficacy but also a promising candidate (i.e., Ce6-RCDs) for multimodal FL/PA/PT imaging-guided and single-NIR-laser-triggered synergistic PTT/PDT for cancers by a reduced irradiation power.

PVP intercalated metallic WSe2 as NIR photothermal agents for efficient tumor ablation

Transition metal dichalogenides (TMDCs) with unique layered structures hold promising potential as transducers for photothermal therapy. However, the low photothermal conversion efficiency and poor stability in some cases limit their practical applications. Herein, we demonstrate the fabrication of ultrathin homogeneous hybridized TMDC nanosheets and their use for highly efficient photothermal tumor ablation. In particular, the nanosheets were composed of metallic WSe₂ intercalated with polyvinylpyrrolidone (PVP), which was facilely prepared through a solvothermal process from the mixture of selenourea crystals, WCl₆ powder along with PVP polymeric nanogel. Our characterizations revealed that the obtained nanosheets exhibited excellent photothermal conversion efficiency, therapeutic demonstration with improved biocompatibility and physiological stability attributing to the combined merits of metallic phase of WSe₂ and hydrophilic PVP insertion. Both the histological analysis of vital organs and in vitro/in vivo tests confirmed the nanosheets as actively effective and biologically safe in this phototherapeutic technique. Findings from this non-invasive experiment clearly emphasize the explorable therapeutic efficacy of the layered-based hybrid agents in future cancer treatment planning procedures.

2D MoS2 -Based Nanomaterials for Therapeutic, Bioimaging, and Biosensing Applications

Molybdenum disulfide (MoS₂ ), a typical layered 2D transition metal dichalcogenide, has received colossal interest in the past few years due to its unique structural, physicochemical, optical, and biological properties. While MoS₂ is mostly applied in traditional industries such as dry lubricants, intercalation agents, and negative electrode material in lithium-ion batteries, its 2D and 0D forms have led to diverse applications in sensing, catalysis, therapy, and imaging. Herein, a systematic overview of the progress that is made in the field of MoS₂ research with an emphasis on its different biomedical applications is presented. This article provides a general discussion on the basic structure and property of MoS₂ and gives a detailed description of its different morphologies that are synthesized so far, namely, nanosheets, nanotubes, and quantum dots along with synthesis strategies. The biomedical applications of MoS₂ -based nanocomposites are also described in detail and categorically, such as in varied therapeutic and diagnostic modalities like drug delivery, gene delivery, phototherapy, combined therapy, bioimaging, theranostics, and biosensing. Finally, a brief commentary on the current challenges and limitations being faced is provided, along with a discussion of some future perspectives for the overall improvement of MoS₂ -based nanocomposites as a potential nanomedicine.

Multimodal Cancer Theranosis Using Hyaluronate-Conjugated Molybdenum Disulfide

Among various 2D nanomaterials, molybdenum disulfide (MoS₂ ) exhibits unique visible photoluminescence with high absorption at the near-infrared (NIR) range. Despite these optical properties, the efforts to use MoS₂ nanomaterials for optical imaging and photothermal therapy are hampered by their instability and low intracellular delivery efficiency. Multifunctional MoS₂ conjugated with hyaluronate (HA) for cancer theranosis is reported herein. HA facilitates the delivery of MoS₂ to tumor cells by the HA-receptor mediated endocytosis. In BALB/c nude mice inoculated with a colorectal cancer cell line of HCT116, HA-MoS₂ conjugates appear to be accumulated in the primary tumor at a content more than that in the liver and kidney. The disulfide bonding between MoS₂ and thiolated HA seems to degrade in the cytoplasm, releasing MoS₂ sheets in stacks and enhancing luminescence efficiency. The HA-MoS₂ conjugates are readily detected via photoacoustic imaging as well as upconversion and downconversion fluorescence imaging. With NIR light illumination, HA-MoS₂ conjugates enable highly effective photothermal tumor ablation. All these results confirm the promising potential of HA-MoS₂ conjugates for cancer theranosis.

Dual-template cascade synthesis of highly multi-branched Au nanoshells with ultrastrong NIR absorption and efficient photothermal therapeutic intervention

A universal dual-template cascade strategy for the synthesis of multi-branched gold nanoshells with ultrastrong NIR absorption for tumor photothermal therapy.