High Near-infrared Absorbance Research Articles

Sub-20 nm Core-Shell-Shell Nanoparticles for Bright Upconversion and Enhanced Förster Resonant Energy Transfer.

Upconverting nanoparticles provide valuable benefits as optical probes for bioimaging and Förster resonant energy transfer (FRET) due to their high signal-to-noise ratio, photostability, and biocompatibility; yet, making nanoparticles small yields a significant decay in brightness due to increased surface quenching. Approaches to improve the brightness of UCNPs exist but often require increased nanoparticle size. Here we present a unique core-shell-shell nanoparticle architecture for small (sub-20 nm), bright upconversion with several key features: (1) maximal sensitizer concentration in the core for high near-infrared absorption, (2) efficient energy transfer between core and interior shell for strong emission, and (3) emitter localization near the nanoparticle surface for efficient FRET. This architecture consists of β-NaYbF4 (core) @NaY0.8-xErxGd0.2F4 (interior shell) @NaY0.8Gd0.2F4 (exterior shell), where sensitizer and emitter ions are partitioned into core and interior shell, respectively. Emitter concentration is varied (x = 1, 2, 5, 10, 20, 50, and 80%) to investigate influence on single particle brightness, upconversion quantum yield, decay lifetimes, and FRET coupling. We compare these seven samples with the field-standard core-shell architecture of β-NaY0.58Gd0.2Yb0.2Er0.02F4 (core) @NaY0.8Gd0.2F4 (shell), with sensitizer and emitter ions codoped in the core. At a single particle level, the core-shell-shell design was up to 2-fold brighter than the standard core-shell design. Further, by coupling a fluorescent dye to the surface of the two different architectures, we demonstrated up to 8-fold improved emission enhancement with the core-shell-shell compared to the core-shell design. We show how, given proper consideration for emitter concentration, we can design a unique nanoparticle architecture to yield comparable or improved brightness and FRET coupling within a small volume.

Direct-Write Dewetting of High Melting Temperature Metals on Flexible Substrates

Microelectromechanical systems (MEMS) are pervasive in modern technology due to their reliability, small foot print, and versatility of function. While many of the manufacturing techniques for MEMS devices stem from integrated circuit (IC) manufacturing, the wide range of designs necessitates more varied processing techniques. Here, new details of a scanning laser based direct-write dewetting technique are presented as an expansion of previous demonstrations. For the first time, the ability to pattern a high melting temperature and high reflectance metallic thin films of Ni and Ag, respectively, on polymer substrates is reported. Novel methods for reducing the power necessary for processing highly reflective films are demonstrated by depositing very thin films of high near-infrared absorbance.

Cationic Defect Engineering for Controlling the Infrared Absorption of Hexagonal Cesium Tungsten Bronze Nanoparticles.

Cesium tungsten bronzes (Cs0.32WO3) have attracted much attention as a near-infrared absorbing material. We report the successful synthesis of highly crystalline and high purity Cs0.32WO3 nanoparticles through a spray pyrolysis route. Careful analyses disclosed the presence of cationic defects, that is, a tungsten deficiency and insufficient Cs doping in the Cs0.32WO3 nanoparticles. These cationic defects can be controlled by facile heat treatment in a mildly reducing atmosphere. In particular, we clarify that the tungsten deficiency is a key factor among the cationic defects to obtain high near-infrared absorption properties. Furthermore, this study clearly demonstrates the precise tunability of the optical properties by means of the lattice constants of the Cs0.32WO3 crystal. The realized range of lattice constants is significantly wider than those previously reported. These findings should contribute to the engineering of Cs0.32WO3 structure and properties.

Multifunctional inhibitors of β-amyloid aggregation based on MoS2/AuNR nanocomposites with high near-infrared absorption.

Recent advances in nanotechnology have developed a lot of opportunities for biological applications. In this work, multifunctional MoS2/AuNR nanocomposites with unique high NIR absorption were designed via combining MoS2 nanosheets and gold nanorods (AuNRs). The nanocomposites were synthesized through electrostatic self-assembly and showed high stability and good biocompatibility. Then they were used to modulate the aggregation of amyloid-β peptides, destabilize mature fibrils under NIR irradiation, and eliminate Aβ-induced ROS against neurotoxicity. The inhibition and destabilization effects were confirmed by Thioflavin T (ThT) fluorescence assay and transmission electron microscopy (TEM). Cell viability assay and ROS assay revealed that MoS2/AuNR nanocomposites could alleviate Aβ-induced oxidative stress and cell toxicity. More importantly, both MoS2 nanosheets and AuNRs can be used as NIR photothermal agents, MoS2/AuNR nanocomposites have enhanced ability of disrupting Aβ fibrils and improved cell viability by generating local heat under low power NIR irradiation. Our results provide new insights into the design of new multifunctional systems for the treatment of amyloid-related diseases.

Multifunctional fluorescent PEGylated fluorinated graphene for targeted drug delivery: An experiment and DFT study

A facile strategy to synthesize multifunctional nanosized fluorinated graphene oxide (FGO), a novel nanocarrier to controllably and specifically deliver single or mixed anticancer drugs, was demonstrated. FGO was prepared by a mild process to tune its size into nanoscale and modify its surface with oxygen groups, and then functionalize with folic acid (FA) pre-linked amino-polyethylene glycol (PEG), rendering good solubility and specifical targetability toward cancer cells with FA receptors. Moreover, anticancer drugs of doxorubicin and camptothecin were effectively loaded onto FGO-PEG-FA separately or together in a well-controlled manner, and density functional theory calculations revealed that non-covalent interactions were the driving forces for drug loading and fluorine atoms provided more active sites for intermolecular interactions. Good control over surface and structure further endowed FGO unique and roust photoluminescence (PL) as well as high near infrared (NIR) absorbance. The former for the first time made FGO an excellent sensor to visually monitor drug loading by inner filter effects, while the latter guaranteed FGO an effective photothermal therapy (PTT) agent. Based on these, a three-in-one therapy model combined with mixed drug treating and PTT was constructed, and further cancer inhibition experiments revealed that remarkably higher treatment effect was achieved compared to single or two-in-one therapy. The presented work to design, synthesize and modify FGO as a novel nanocarrier and study on the interactions with drugs provided novel insights into developing new drug delivery systems, and the unique PL combined with high NIR absorbance made this work potentially valuable in many fields.

Hydrogen Sulfide-Activatable Second Near-Infrared Fluorescent Nanoassemblies for Targeted Photothermal Cancer Therapy.

Near-infrared (NIR)-II fluorescence agents hold great promise for deep-tissue photothermal therapy (PTT) of cancers, which nevertheless remains restricted by the inherent nonspecificity and toxicity of PTT. In response to this challenge, we herein develop a hydrogen sulfide (H2S)-activatable nanostructured photothermal agent (Nano-PT) for site-specific NIR-II fluorescence-guided PTT of colorectal cancer (CRC). Our in vivo studies reveal that this theranostic Nano-PT probe is specifically activated in H2S-rich CRC tissues, whereas it is nonfunctional in normal tissues. Activation of Nano-PT not only emits NIR-II fluorescence with deeper tissue penetration ability than conventional fluorescent probes but also generates high NIR absorption resulting in efficient photothermal conversion under NIR laser irradiation. Importantly, we establish NIR-II imaging-guided PTT of CRC by applying the Nano-PT agent in tumor-bearing mice, which results in complete tumor regression with minimal nonspecific damages. Our studies thus shed light on the development of cancer biomarker-activated PTT for precision medicine.

Blue Te Nanoneedles with Strong NIR Photothermal and Laser-Enhanced Anticancer Effects as "All-in-One" Nanoagents for Synergistic Thermo-Chemotherapy of Tumors.

The conventional blue Te nanostructures exhibit strong photoabsorption in the near-infrared (NIR) region but have ultralong lengths (tenths of micrometers), while purple Te nanostructures with short lengths (such as nanodots and nanorods) show extremely low intensity of the NIR band. These Te nanostructures cannot achieve simultaneously both the suitable size and high NIR absorption, undoubtedly hindering their bioapplication. Herein, blue Te nanoneedles are prepared through a facile one-pot reduction route for the first time, and they have strong NIR absorbance while maintaining the shortened length (<500 nm). Compared to purple Te nanorods, blue Te nanoneedles have higher photothermal conversion efficiency using a 915 nm laser and exhibit laser-enhanced antioxidative activity toward scavenging of free radicals. These blue nanoneedles show significant discrimination in cytotoxicity toward different cell-lines, and demonstrate anticancer activity induced by mitochondrial dysfunction. Furthermore, when blue Te nanoneedles are injected in tumors of mice, tumors can be detected by thermal/photoacoustic imaging, and satisfactory therapeutic effects are achieved through the synergistic thermo-chemotherapy in contrast to the limited therapeutic effect of Te-alone treatment. Therefore, these blue Te nanoneedles can be served as a novel theranostic nanoagent for simultaneous multimodal imaging and synergistic thermo-chemotherapy for tumors.

Fluorescence-switchable ultrasmall fluorinated graphene oxide with high near-infrared absorption for controlled and targeted drug delivery

Although fluorinated graphene (FG) exhibits numerous excellent properties, its chemical inertness and hydrophobicity markedly limit its further application. Here, we report a novel strategy to synthesize nanosized water-soluble fluorinated graphene oxide (FGO) sheets that exhibit bright fluorescence (robust under both acidic and alkaline conditions), high near-infrared absorption and pH-responsive drug delivery. Structural adjustment of sizes into nanoscale (∼50 nm) endows FGO with superior photothermal performance surpasses those of FG and graphene oxide, and the fluorescence resonance energy transfer interactions between FGO and drugs allows switchable luminescence for monitoring the drug loading and release. The chemical introduction of oxygen facilitates the modification of FGO with folic acid for the first time and induces targeted endocytose into cancer cells. Enhanced hyperthermia, targeting specificity, and intracellular acid condition-triggered drug release guarantee the excellent therapeutic effects. Fine control over the structure and chemistry of FG, combined with high photoluminescence, enhanced photothermal effects, and targeted drug delivery makes our method potentially valuable in many fields.

Renal-clearable quaternary chalcogenide nanocrystal for photoacoustic/magnetic resonance imaging guided tumor photothermal therapy

Ultrasmall Cu2ZnSnS4 (CZTS) nanocrystals with high near infrared (NIR) photothermal conversion abilities and peroxidase-mimic properties are synthesized and functionalized with bovine serum albumin (BSA) for rapid clearance multifunctional theranostic platform. Due to the presence of Cu (I) of CZTS@BSA, H2O2 could be decomposed to produce highly reactive oxygen species (ROS), catalyzed by intrinsic peroxidase like activity of CZTS. The CZTS@BSA possesses high NIR absorption and excellent photoacoustic (PA) imaging abilities. The as-prepared CZTS@BSA is also reported as an efficient T1 contrast agent for in vivo MR imaging. Therefore, in vivo distribution and rapid renal clearance of CZTS@BSA are successfully tracked by PA/MR dual-modal-imaging and further proved by ICP-MS analysis. Systemic acute toxicity evaluation indicates CZTS@BSA have good biocompatibility to normal tissues and blood. All results reveal that CZTS@BSA could act as a rapid clearance theranostic nanoplatform for dual-modal-imaging guided tumor PTT.

Nano-sized paramagnetic and fluorescent fluorinated carbon fiber with high NIR absorbance for cancer chemo-photothermal therapy.

Nano-sized fluorinated carbon fiber possesses unique charge distribution and special chemical bonds and holds great promise in biomedicine. However, its synthesis remains a big challenge on account of the chemical inertness and strong hydrophobicity of C-F bonds. Herein, an up-bottom method to prepare nano-sized and water-soluble fluorinated carbon fiber oxide (FCO) with tunable lengths and adjustable fluorine levels was first developed. It was found that the effective control over structure and composition endowed the FCO with high photoluminescence (PL) and near-infrared (NIR) light absorbance, which was further employed to monitor the drug loading by turn-off PL and treat cancer by photothermal therapy (PTT). We also reported the first experimental example of paramagnetic FCO, whose novel paramagnetism was generated by point defects from fluorine invasion. Moreover, the FCO was noncovalently functionalized with polyvinylpyrrolidone, loaded with doxorubicin of high capacity (1.15 mg mg-1) and exhibited acid-triggered and photothermally enhanced drug release behavior. The application of FCO in cancer treatment achieved much better therapeutic effects than single chemotherapy or PTT. This work established FCO as a novel nano-carrier with high PL, NIR absorbance, paramagnetism, and drug loading capacity, and demonstrated its first application in cancer chemo-photothermal therapy.

BSA-modified poly(pyrrole-3-carboxylic acid) nanoparticles as carriers for combined chemo-photothermal therapy.

A facile reverse microemulsion method was developed for the synthesis of homogenous poly(pyrrole-3-carboxylic acid) (PPyCOOH) nanoparticles, which used n-heptane as the oil phase, sodium dodecyl sulfate as the surfactant, 1-butanol as the co-surfactant and pyrrole-3-carboxylic solution as the aqueous phase. The obtained PPyCOOH nanoparticles had uniform sizes, high near-infrared absorption and abundant functional groups. To improve their stability and enhance the tumor inhibition rate, the PPyCOOH nanoparticles were modified with bovine serum albumin (BSA) and doxorubicin (DOX). The as-fabricated drug delivery system (DOX@BSA-PPyCOOH) combining photothermal therapy and chemotherapy exhibited pH-sensitive and near infrared laser controlled drug release, which was beneficial for drug enrichment in the tumor and for reducing the toxicity and side effects in normal tissue. Combined chemo-photothermal therapy in vivo revealed that the tumors were completely eliminated and no obvious toxicity was found in the major organs, suggesting that DOX@BSA-PPyCOOH nanoparticles are an efficient nanoagent for cancer treatment.

Fluorescence turn-off Ag/fluorinated graphene composites with high NIR absorption for effective killing of cancer cells and bacteria.

The unique structure and special chemical surface make fluorinated graphene-silver (FG-Ag) hold great promise in many biological fields. However, the synthesis of this nano-composite has not yet been achieved mostly due to the strong hydrophobicity and inertness of C-F bonds. Herein, we demonstrate an interesting concept of multifunctional FG-Ag and integrate it as a highly effective targeted drug carrier, photothermal therapy (PTT) and antibacterial agent. To achieve this, the F-sacrificing method is first employed to enrich FG with oxygen groups (FGO), which then serve as necessary and active reaction sites for controlled deposition of Ag nanoparticles (AgNPs) and modification of cancer targeting molecules. Interestingly, AgNPs well quench FGO's fluorescence, and FGO-Ag then acts as another effective quencher for the anticancer drug doxorubicin, all of which guarantee it as a novel sensor to visually monitor drug loading by "turn-off" fluorescence. More importantly, this nano-composite also possesses special targeting toward cancer cells; it exhibits high near-infrared absorption for PTT and shows effective antibacterial activity. This study establishes FGO-Ag as a novel nanocarrier with good targeting efficiency, high NIR absorption and drug loading and demonstrates its first application in antibacterial and cancer chemo-photothermal treatments.

Tumor Theranostics of Transition Metal Ions Loaded Polyaminopyrrole Nanoparticles.

Polypyrrole (PPy) nanoparticles (NPs) possess high near-infrared absorption and good biosafety, showing the potentials as photothermal therapeutic materials. However, the single function and the weak diagnostic function limit the further combination with other functional units to achieve theranostics. In this work, polyaminopyrrole (PPy-NH2) is demonstrated as the alternative of PPy for preparing NPs. Because of the amino group, metal ions, such as Cu(II) and Fe(III) can be loaded in PPy-NH2 NPs, which extends the applications in multimodal theranostics. Systematical studies reveal that the contribution of Cu(II) in multimodal theranostics is greater than Fe(III). Cu can enhance T1 response signal for magnetic resonance imaging (MRI) and be released controllably in the organism, leading to the effect of chemotherapy. Therefore, Cu(II) and Fe(III) co-loaded PPy-NH2 NPs are defined as CuPPy-NH2 NPs. Experimental results indicate that the optimal size of CuPPy-NH2 NPs is 50.2 nm. The photothermal transduction efficiency is 76.4%. After thermochemotherapy, a complete ablation of human oral epithelial carcinoma tumors is observed. No tumor recurrence is found.Methods: Cu(II) and Fe(III) co-loaded PPy-NH2 NPs are prepared through oxidation polymerization by mixing Py-NH2, CuCl2, and FeCl3 in water under stirring at room temperature, which are defined as CuPPy-NH2 NPs. The as-prepared CuPPy-NH2 NPs are tested with a variety of cell and animal experiments for tumor theranostics.Results: CuPPy-NH2 NPs have good light stability, photothermal stability, biosafety and low toxicity. The optimal size of theranostic CuPPy-NH2 NPs is 50.2 nm, which present a photothermal transduction efficiency of 76.4%. The doped Cu(II) ions also show chemotherapeutic behavior. After thermochemotherapy, a complete ablation of human oral epithelial carcinoma tumors is observed. No tumor recurrence is found. Because of the unpaired electron in Cu atomic orbits, CuPPy-NH2 NPs also show T1-weighted magnetic resonance imaging.Conclusions: This kind of transition metal-doped polymer gives a competitive approach for designing and fabricating multimodal theranostic nanodevices, which shows the potential in tumor treatment.

Synthesis of BSA-Coated BiOI@Bi2 S3 Semiconductor Heterojunction Nanoparticles and Their Applications for Radio/Photodynamic/Photothermal Synergistic Therapy of Tumor.

Developing an effective theranostic nanoplatform remains a great challenge for cancer diagnosis and treatment. Here, BiOI@Bi2 S3 @BSA (bovine serum albumin) semiconductor heterojunction nanoparticles (SHNPs) for triple-combination radio/photodynamic/photothermal cancer therapy and multimodal computed tomography/photoacoustic (CT/PA) bioimaging are reported. On the one hand, SHNPs possess strong X-ray attenuation capability since they contain high-Z elements, and thus they are anticipated to be a very competent candidate as radio-sensitizing materials for radiotherapy enhancement. On the other hand, as a semiconductor, the as-prepared SHNPs offer an extra approach for reactive oxygen species generation based on electron-hole pair under the irradiation of X-ray through the photodynamic therapy process. This X-ray excited photodynamic therapy obviously has better penetration depth in bio-tissue. What's more, the SHNPs also possess well photothermal conversion efficiency for photothermal therapy, because Bi2 S3 is a thin band semiconductor with strong near-infrared absorption that can cause local overheat. In vivo tumor ablation studies show that synergistic radio/photodynamic/photothermal therapy achieves more significant therapeutic effect than any single treatment. In addition, with the strong X-ray attenuation and high near-infrared absorption, the as-obtained SHNPs can also be applied as a multimodal contrast agent in CT/PA imaging.

Yolk-Shell Nanostructure: An Ideal Architecture to Achieve Harmonious Integration of Magnetic-Plasmonic Hybrid Theranostic Platform.

Magnetic-plasmonic hybrid nanoparticles (MPHNs) have attracted great interest in cancer theranostics. However, the relaxivity of the magnetic component is typically reduced by the plasmonic component in conventional core-shell structured MPHNs, due to the presence of a water-impenetrable coating which severely restricts the proximity of protons to the magnetic portion. To circumvent this issue, yolk-shell structured MPHNs comprising a Fe3 O4 core within a hollow cavity encircled by a porous Au outer shell are designed. As expected, the introduction of hollow cavity between the magnetic and plasmonic portions significantly prevents the decline in relaxivity of the Fe3 O4 core caused by the Au layer. Moreover, in addition to conferring high near-infrared absorption to plasmonic component, the hollow cavity and the pores in the outer shell can also provide a large storage space and release channels for anticancer drugs. Furthermore, the multicomponent nanoparticles (NPs) still have a compact size of less than 100 nm to ensure efficient tumor accumulation. Taken together, the yolk-shell Fe3 O4 @Au NPs can be regarded as an ideal magnetic-plasmonic theranostic platform for magnetic resonance/photoacoustic/positron emission tomography multimodal imaging and light-activated chemothermal synergistic therapy.

Core-shell and co-doped nanoscale metal-organic particles (NMOPs) obtained via post-synthesis cation exchange for multimodal imaging and synergistic thermo-radiotherapy

Nanoscale metal-organic particles (NMOPs) have recently shown great promise in the area of nanomedicine owing to their tunable compositions, highly enriched functionalities, well-defined sizes/shapes and intrinsic biodegradability. Herein, we describe the fabrication of NMOPs with both core-shell and co-doped structures via a post-synthesis cation exchange method for applications in multimodal imaging and combined photothermal and radiation therapy of cancer. Template NMOPs containing Mn2+ and IR825, a near-infrared (NIR) dye, are first synthesized and then mixed with Hf4+ to obtain core-shell and co-doped Mn/Hf-IR825 NMOPs depending on the dose of added Hf4+ ions. In these NMOPs, Mn2+ offers strong T1 magnetic resonance (MR) contrast, Hf4+ is a high-Z element with excellent computed tomography signal enhancement ability and radio-sensitization capability, and IR825 exhibits rather high NIR absorbance. After coating with polydopamine (PDA) and further conjugation with polyethylene glycol (PEG), the co-doped Mn/Hf-IR825@PDA-PEG particles (NMOP-PEG) showed efficient tumor-homing ability after intravenous injection, as illustrated by MR and photoacoustic (PA) imaging. Utilizing NMOP-PEG achieved excellent tumor killing efficacy through in vivo photothermal and radiation synergistic therapy in our mouse tumor model experiments. Importantly, our NMOP-PEG showed no appreciable toxicity to the treated mice and could be efficiently excreted. Our work presents a facile method to fabricate NMOP-PEG with multi-component structures as a biodegradable, multifunctional nanoplatform for multimodal image-guided combination cancer therapy.

High near-infrared absorbing Cu5FeS4 nanoparticles for dual-modal imaging and photothermal therapy.

Multifunctional nanomaterials have shown excellent and promising properties for cancer diagnosis and treatment. Herein, we have developed iron doped copper sulfide (Cu5FeS4) nanoparticles with a non-covalent polyethylene glycol (PEG) coating (Cu5FeS4-PEG) for tumor dual-modal imaging and photothermal therapy (PTT). The obtained Cu5FeS4-PEG nanoparticles with high near-infrared absorbance could be used for phototoacoustic (PA) imaging and PTT, whereas Fe(3+) doping offer the nanoparticles the additional property for magnetic resonance (MR) imaging. As shown by PA imaging, Cu5FeS4-PEG exhibit a high tumor uptake (∼10% ID g(-1)) after intravenous injection. In vitro and in vivo cancer treatment further confirm that Cu5FeS4-PEG could act as a novel therapeutic agent for PTT of cancer cells. Our study further promotes the potential applications of multifunctional nanomaterials in a range of tumor diagnoses and treatments.

One-pot synthesis of PEGylated plasmonic MoO3–x hollow nanospheres for photoacoustic imaging guided chemo-photothermal combinational therapy of cancer

Engineering design of plasmonic nanomaterials as on-demand theranostic nanoagents with imaging, drug carrier, and photothermal therapy (PTT) functions have profound impact on treatment of cancer. Here, a facile ‘one-pot’ template-free hydrothermal route was firstly developed for synthesis of plasmonic oxygen deficiency molybdenum oxide hollow nanospheres functionalized by poly(ethylene glycol) (PEG-MoO3–x HNSs). The as-prepared PEG-MoO3–x HNSs not only have good biocompatibility but also exhibit obvious localized surface plasmon resonance (LSPR) absorption in the near-infrared (NIR) region. Especially, due to its intrinsic mesoporous properties and effective photothermal conversion efficiency upon 808-nm NIR laser irradiation, the PEG-MoO3–x HNSs can be applied as a pH/NIR laser dual-responsive camptothecin (CPT) drug delivery nanoplatform for chemotherapy as well as PTT to cancer cells. A remarkably improved synergistic therapeutic effect to pancreatic (PANC-1) tumor-bearing mice was obtained compared to the result of chemotherapy or PTT alone. Apart from its application for drug delivery, the PEG-MoO3–x HNSs can also be employed as an effective contrast nanoagent for photoacoustic (PAT) imaging because of its high NIR absorption, making it promising as a theranostic nanoagent for PAT imaging-guided chemo-photothermal combinational cancer therapy in the nanomedicine field.

Chemically exfoliated WS2 nanosheets efficiently inhibit amyloid β-peptide aggregation and can be used for photothermal treatment of Alzheimer’s disease

Polymerization of amyloid-beta peptide (A beta) into amyloid fibrils is a critical step in the pathogenesis of Alzheimer's disease (AD). Inhibition of A beta aggregation and destabilization of preformed A beta fibrils have promising effects against AD and have been used in clinic trials. Herein, we demonstrate, for the first time, the application of WS2 nanosheets, to not only effectively inhibit A beta aggregation, but also dissociate preformed A beta aggregates upon near infrared (NIR) irradiation. Additionally, the biocompatible WS2 nanosheets possess the ability to cross the blood-brain barrier (BBB) to overcome the limitations of most previously reported A beta inhibitors. Through van der Waals and electrostatic interactions between A beta 40 and WS2, A beta 40 monomers can be selectively adsorbed on the surface of the nanosheet to inhibit the A beta 40 aggregation process. Intriguingly, the unique high NIR absorption property of WS2 enables amyloid aggregates to be dissolved upon NIR irradiation. These results will promote biological applications of WS2 and provide new insight into the design of multifunctional nanomaterials for AD treatment.

Investigation on Single-walled Carbon Nanotubes-Liposomes Conjugate to Treatment Tumor with Dual-mechanism.

Single-walled carbon nanotubes (SWNT) have been widely explored as carriers for drug delivery because of their large surface area, high near-infrared absorption coefficient and facile transport through cellular membranes. In this study, Lysine (Lys) modified SWNT-liposomes conjugate loaded with doxorubicin (DOX) was designed to enhance the targeted drug delivery and antitumor effect. The conjugate (DOX-Lys/SWNT-Lip) was prepared with pH gradient methods, and the mean particle size and drug entrapment efficiency were 223±5.9 nm and 85.9 %, respectively. In vitro drug release study showed that DOX released much slowly from DOX-Lys/SWNT-Lip than from DOX solution, but faster than that of DOX-Lys/SWNT. DOX-Lys/SWNT-Lip could efficiently cross the cell membrane and afford higher anti-tumor efficacy on MCF-7 cells in vitro. For in vivo experiment, normal saline (N.S.), and DOX or DOX-Lys/SWNTLip were given to the S180 tumor bearing mice by i.v. administration, and followed by exposing the tumor site to nearinfrared laser (NIR) irradiation at 808 nm for 2 min. The relative tumor volumes in DOX-Lys/SWNT-Lip group and DOX group were obviously smaller than those of N.S. group. When combined with NIR laser irradiation, the suppression on tumor growth was much stronger. In conclusion, this study may provide potentially viable clinical strategies for tumor treatment with chemotherapy and photothermal therapy dual-mechanism.