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.

The biocompatibility of quantum dot probes used for the targeted imaging of hepatocellular carcinoma metastasis

Semiconductor quantum dots (QDs) have several photo-physical advantages over organic dyes making them good markers in biomedical application. We used CdSe/ZnS QDs with maximum emission wavelength of 590nm (QD590) linked to alpha-fetoprotein (AFP) monoclonal antibody (Ab) to detect AFP in cytoplasm of human hepatocellular carcinoma (HCC) cell line HCCLM6. For the in vivo studies, we used QD-AFP-Ab probes for targeted imaging of human HCC xenograft growing in nude mice by injecting them into the tail vein. In addition, the cytotoxicity in vitro, the acute toxicity in vivo, the hemodynamics and tissue distribution of these probes were also investigated. The results in vitro and in vivo indicate that our QD-based probes have good stability, specificity and biocompatibility for ultrasensitive fluorescence imaging of molecular targets in our liver cancer model system.

Diet and cancer of the colon and rectum: a case-control study in China

A case-control study was carried out in Harbin city to assess the role of diet in the aetiology of colorectal cancer. A total of 336 incident cases of histologically confirmed colorectal cancer (111 colon cancer and 225 rectal cancer) and an equal number of controls with other non-neoplastic diseases were interviewed in hospital wards. Data concerning the average frequency of consumption and amount consumed of single food items were obtained by a dietary history questionnaire. Odds ratios and their confidence limits were computed. Multiple regression for risk status was also used. Vegetables, particularly green vegetables, chives and celery, have a strong protective effect against colorectal cancer. Reduced consumption of meat, eggs, bean products and grain was associated with increasing risk for cancer of the rectum. Alcohol intake was found to be an important risk factor for developing colon cancer and male rectal cancer.

Increased expression of CXCR3 and its ligands in patients with vitiligo and CXCL10 as a potential clinical marker for vitiligo

BACKGROUND

Vitiligo is a skin disorder characterized by loss of melanocytes from the epidermis. A recent study reported that CXCL10 is critical for the progression and maintenance of depigmentation in a mouse model of vitiligo, but there is very limited clinical data regarding this issue and little is known about the dynamic changes or correlations with disease severity of these chemokines throughout the disease course.

OBJECTIVES

To present clinical data that supports and identifies the pathway of CXCR3 and its ligands in T-lymphocytic cell recruitment in vitiligo.

METHODS

Cytometric bead array, flow cytometry, quantitative real-time polymerase chain reaction and immunohistology were used to examine their systemic and local expression in 80 patients with vitiligo and 40 controls.

RESULTS

We showed that serum CXCL9 and CXCL10 were significantly elevated in patients with vitiligo and were higher in patients in progressive stages than in stable stages. The relative expression of CXCR3 mRNA in peripheral blood mononuclear cells was higher in vitiligo. There were higher percentages of both circulating CXCR3(+) CD4(+) and CXCR3(+) CD8(+) T cells in patients with progressive vitiligo compared with controls, while only the expression of CXCR3(+) CD8(+) T cells increased in patients with stable vitiligo. Histological findings also demonstrated an abundance of CXCR3(+) cells within vitiligo lesions. Furthermore, serum CXCL10 levels were associated with Vitiligo Area Scoring Index scores of patients with progressive vitiligo and were reduced after successful treatment.

CONCLUSIONS

The CXCL10/CXCR3 axis mediates T-cell recruitment into the skin in progressive vitiligo. Blocking this chemotactic mechanism may present a new form of therapy. Serum CXCL10 may be a novel biomarker in monitoring disease activity and guiding treatment of progressive vitiligo.

Evaluations of cellulose accessibilities of lignocelluloses by solute exclusion and protein adsorption techniques

Cellulose accessibilities of a set of hornified lignocellulosic substrates derived by drying the never dried pretreated sample and a set of differently pretreated lodgepople pine substrates, were evaluated using solute exclusion and protein adsorption methods. Direct measurements of cellulase adsorption onto cellulose surface of the set of pretreated substrates were also carried out using an in situ UV-Vis spectrophotometric technique. The cellulose accessibilities measured by the solute exclusion and a cellulose-binding module (CBM)-containing green fluorescent protein (TGC) adsorption methods correlate well for both sets of samples. The substrate enzymatic digestibilities (SEDs) of the hornified substrates are proportional to the measured cellulose accessibilities. Approximately over 90% of the SED was contributed by the accessible pore surfaces of the hornified substrates, suggesting that the substrate external surface plays a minor role contributing to cellulose accessibility and SED. The cellulose accessibilities of the pretreated substrates correlated well with the amounts of cellulase adsorbed. The SEDs of these substrates directly correlated with the amounts of adsorbed cellulase.

Diet and cancer of the stomach: a case-control study in China

A case-control study focusing on the role of single food items was undertaken in the Heilongjiang area, 241 patients with histologically verified stomach cancer and an equal number of controls (with non-neoplastic diseases) matched by age, sex and area of residence being interviewed during a 2-year period. Questions asked covered economic status, occupation, histories of smoking and drinking, diet and dietary habits and disease history. Data concerning the average frequency and quantity of consumption of single food items were obtained by the same interviewer. An inverse association between the consumption of vegetables and stomach cancer was observed whereas high intake of potatoes and of salted and fermented soya paste appeared to be high-risk factors. Specifically, Chinese cabbage plays an important role in reducing the risk of developing stomach cancer.

Optical nonlinear absorption and refraction of CdS and CdS-Ag core-shell quantum dots

The CdS and CdS-Ag core-shell quantum dots (QDs) have been prepared. The nanostructures of the QDs were revealed by transmisson electron microscopy and absorption spectra, respectively. The third-order nonlinear optical properties of the core-shell QDs have been studied by using Z-scan technique with femtosecond pulses at the wavelength of 790 nm. The value of the effective nonlinear absorption coefficient beta(eff) of CdS-Ag QDs is measured to be about 16.8 cm/GW, which is about 400 times larger than that of bare CdS QDs of 3.9 x 10(-2) cm/GW. The nonlinear refraction index gamma of CdS-Ag QDs is about -2.3 x 10(-4) cm(2)GW, which is about 200 times larger than that of bare CdS QDs of 1.0 x 10(-6) cm(2)GW.

Surface functionalization of ZnO nanotetrapods with photoactive and electroactive organic monolayers

Two strategies have been explored for organic functionalizations of ZnO nanotetrapods via anchoring groups of carboxylate and phosphonate. With these methods, oleyl chains were assembled on the surfaces of the ZnO nanotetrapods, significantly enhancing their solubility in nonpolar solvents, such as chloroform and toluene. The surface functionalization strategies have been extended to electroactive and photoactive molecules such as protoporphyrin and C(60) on the ZnO nanotetrapods. The surface-modified ZnO nanotetrapods were characterized comprehensively, revealing a uniform, covalently linked monolayer assembled on the surface. This work opens a broad perspective for the application of the organically functionalized nanotetrapods in optoelectronics and biomedicine.

A gene nanocomplex conjugated with monoclonal antibodies for targeted therapy of hepatocellular carcinoma

To enhance tumor-targeting abilities and therapeutic efficiency, a monoclonal antibody-conjugated gene nanocomplex was herein designed. The biodegradable cationic polyethylenimine-grafted-α,β-poly(N-3-hydroxypropyl)-DL-aspartamide (PHPA-PEI) was used for complexing pDNA to form the PHPA-PEI/pDNA nanoparticle, and then 9B9 mAb, an anti-epidermal growth factor receptor (anti-EGFR) monoclonal antibody, was conjugated to produce the PHPA-PEI/pDNA/9B9 mAb (PP9mN) complex. The PP9mN complex with the diameter of around 300 nm at its optimal weight ratio could be uptaken effectively by SMMC-7721 cells. The cytotoxicity of the PP9mN complex was much lower than that of PEI 25 kD in SMMC-7721, HepG2, Bel-7404 and COS-7 cell lines. The PP9mN complex possessed the highly efficient in vitro gene delivery ability to the hepatocellular carcinoma cells. The in vivo gene expression indicated that PP9mN could target to the tumor tissues effectively. By using the therapeutic AChE gene, it was found that the PP9mN complexes significantly enhanced the anti-tumor effect on tumor-bearing nude mice. Such monoclonal antibody-conjugated gene complex should have great potential applications in liver cancer therapy.

Synthesis of bright upconversion submicrocrystals for high-contrast imaging of latent-fingerprints with cyanoacrylate fuming

High-contrast imaging of latent-fingerprints was obtained by the combination of bright UCPs and CA-fuming.

Tuning gold nanorod-nanoparticle hybrids into plasmonic Fano resonance for dramatically enhanced light emission and transmission

We investigate the optical response of a gold nanorod array coupled with a semicontinuous nanoparticle film. We find that, as the gold nanoparticle film is adjusted to the percolating regime, the nanorod-film hybrids are tuned into plasmonic Fano resonance, characterized by the coherent coupling of discrete plasmonic modes of the nanorod array with the continuum band of the percolating film. Consequently, optical transmission of the percolating film is substantially enhanced. Even more strikingly, electromagnetic fields around the nanorod array become much stronger, as reflected by 2 orders of magnitude enhancement in the avalanche multiphoton luminescence. These findings may prove instrumental in the design of various plasmonic nanodevices.

An oligopeptide ligand-mediated therapeutic gene nanocomplex for liver cancer-targeted therapy

The epidermal growth factor receptor (EGFR) is over-expressed in a wide variety of epithelial-derived cancer cells. In this study, EGFR-targeted gene carriers were designed to complex the therapeutic acetylcholinesterase gene (AChE gene), which suppresses cell proliferation via inactivating mitogen-activated protein kinase and PI3K/Akt pathways in cells, for treatment of EGFR-positive liver cancers. Different amounts of target ligand YC21 (an oligopeptide composed of 21 amino acid units) were coupled with the PEI(600)-CD (PC) vectors composed of β-cyclodextrin (β-CD) and low-molecular-weight polyethylenimine (PEI, Mw 600) to form the EGFR-targeted gene vectors (termed as YPCs). The YPC vectors possessed the highly efficient gene delivery ability to the EGFR-positive liver cancer cells. YPCs could effectively promote AChE gene expression. The YPC/AChE complexes produced excellent gene transfection abilities in EGFR-positive liver cancer cells in vitro and in vivo.

Bifunctional conjugates comprising β-cyclodextrin, polyethylenimine, and 5-fluoro-2'- deoxyuridine for drug delivery and gene transfer

Earlier reports indicated that the conjugates (PEI(600)-CD, PC) of β-cyclodextrin and low-molecular-weight polyethylenimine (PEI, M(w) 600) can be used as efficient gene carriers in glioma cancer therapy. Incorporating anticancer drugs onto PC conjugates may endow them with new and interesting properties for great applications. In this work, FU-PEI(600)-CD (FPC) conjugates comprising PC and 5-fluoro-2'-deoxyuridine (FdUrd) were prepared as new bifunctional anticancer prodrugs with improved therapeutic effects, as well as good gene transfer efficiency. In comparison with free FdUrd, FPC could inhibit proliferation and enhance cytotoxicity on glioma cells. The results of hematoxylin and eosin (HE) staining indicated that C6 cells treated with FPC shrunk more seriously. Unlike FdUrd, cell cycle analysis indicated that C6 cells were primarily arrested in the G1 phase in the presence of FPC. Cellular uptake of FPC in C6 cells was about 10 times higher than that of FdUrd. In addition, the in vitro and in vivo gene transfection indicated that FPC still exhibited good gene expression efficiency. With the ability to deliver drugs and transfer genes, such bifunctional FPC conjugates may have great potential applications in combination therapy of cancers.

Unusual and tunable one-photon nonlinearity in gold-dye plexcitonic Fano systems

Recent studies of the coupling between the plasmonic excitations of metallic nanostructures with the excitonic excitations of molecular species have revealed a rich variety of emergent phenomena known as plexcitonics. Here, we use a combined experimental and theoretical approach to demonstrate new and intriguing aspects in the ultrafast nonlinear responses of strongly coupled hybrid Fano systems consisting of gold nanorods decorated with near-infrared dye molecules. We show that the severely suppressed linear absorption around the Fano dip significantly enhances the unidirectional energy transfer from the plasmons to the excitons and further allows one-photon nonlinearity to be drastically and reversibly tuned. These striking observations are interpreted within a microscopic model stressing on two competing processes: saturated plasmonic absorption and weakened destructive Fano interference from the bleached excitonic absorption. The unusually strong one-photon nonlinearity revealed here provides a promising strategy in fabricating nanoplasmonic devices with both pronounced nonlinearities and good figures of merit.

Plasmon-Enhanced Photoelectrochemical Current and Hydrogen Production of (MoS2-TiO2)/Au Hybrids

Three component hybrid (MoS₂-TiO₂)/Au substrate is fabricated by loading plasmonic Au nanorods on the MoS₂ nanosheets coated TiO₂ nanorod arrays. It is used for photoelectrochemical (PEC) cell and photocatalyst for hydrogen generation. Owing to the charge transfer between the MoS₂-TiO₂ hetero-structure, the PEC current density and hydrogen generation of TiO₂ nanoarrays are enhanced 2.8 and 2.6 times. The broadband photochemical properties are further enhanced after Au nanorods loading. The plasmon resonance of Au nanorods provides more effective light-harvesting, induces hot-electron injection, and accelerates photo-excited charges separation. The results have suggested a route to construct nanohybrid by combining one-dimensional arrays and two-dimensional nanosheets, meanwhile have successfully utilized plasmonic nanorods as a sensitizer to improve the photochemical properties of the semiconductor nanocomposite.

Symmetric and asymmetric Au-AgCdSe hybrid nanorods

This paper describes a facile method for synthesis of Au-AgCdSe hybrid nanorods with controlled morphologies and spatial distributions. The synthesis involved deposition of Ag tips at the ends of Au nanorod seeds, followed by selenization of the Ag tips and overgrowth of CdSe on these sites. By simply manipulating the pH value of the system, the AgCdSe could selectively grow at one end, at both the ends or on the side surface of a Au nanorod, generating a mike-like, dumbbell-like, or toothbrush-like hybrid nanorod, respectively. These three types of Au-AgCdSe hybrid nanorods displayed distinct localized surface plasmon resonance and photoluminescence properties, demonstrating an effective pathway for maneuvering the optical properties of nanocrystals.

Magnetic Plasmon-Enhanced Second-Harmonic Generation on Colloidal Gold Nanocups

The magnetic plasmons of three-dimensional nanostructures have unique optical responses and special significance for optical nanoresonators and nanoantennas. In this study, we have successfully synthesized colloidal Au and AuAg nanocups with a well-controlled asymmetric geometry, tunable opening sizes, and normalized depths ( h/ b, where h is depth and b is the height of the templating PbS nanooctahedrons), variable magnetic plasmon resonance, and largely enhanced second-harmonic generation (SHG). The most-efficient SHG of the bare Au nanocups is experimentally observed when the normalized depth h/ b is adjusted to ∼0.78-0.79. We find that the average magnetic field enhancement is maximized at h/ b = ∼0.65 and reveal that the maximal SHG can be attributed to the joint action of the optimized magnetic plasmon resonance and the "lightning-rod effect" of the Au nanocups. Furthermore, we demonstrate for the first time that the AuAg heteronanocups prepared by overgrowth of Ag on the Au nanocups can synergize the magnetic and electric plasmon resonances for nonlinear enhancement. By the tailoring of the dual resonances at the fundamental excitation and second-harmonic wavelengths, the far-field SHG intensity of the AuAg nanocups is enhanced 21.8-fold compared to that of the bare Au nanocups. These findings provide a strategy for the design of nonlinear optical nanoantennas based on magnetic plasmon resonances and can lead to diverse applications ranging from nanophotonics to biological spectroscopy.

Fano resonances in dipole-quadrupole plasmon coupling nanorod dimers

We theoretically investigate the plasmon coupling in metallic nanorod dimers. A pronounced dip is found in the extinction spectrum due to plasmonic Fano resonance, which is induced by destructive interference between the bright dipole plasmon of a short nanorod and the dark quadrupole plasmon of a long nanorod. This Fano interference can also be explained as the coupling between the bright and dark modes both supported by the whole dimer. The Fano resonance can be tuned by adjusting the spatial or spectral separation between two nanorods in the dimer.

The influence of surface trapping and dark states on the fluorescence emission efficiency and lifetime of CdSe and CdSe/ZnS quantum dots

To investigate the influence of surface trapping and dark states on CdSe and CdSe/ZnS quantum dots (QDs), we studied the absorption, fluorescence intensity and lifetime by using one-and two-photon excitation, respectively. Experimental results show that both one- and two-photon fluorescence emission efficiencies of the QDs enhance greatly and the lifetime increase after capping CdSe with ZnS due to the effective surface passivation. The lifetime of one-photon fluorescence of CdSe and CdSe/ZnS QDs increase with increasing emission wavelength in a supralinear way, which is attributed to the energy transfer of dark excitons. On the contrary, the lifetime of two-photon fluorescence of bare and core-shell QDs decrease with increasing emission wavelength, and this indicates that the surface trapping is the dominant decay mechanism in this case.

miR-124 radiosensitizes human esophageal cancer cell TE-1 by targeting CDK4

Radiotherapy is one of the most important treatments for esophageal cancer, but radioresistance remains a major challenge. Previous studies have shown that microRNAs (miRNAs or miRs) are involved in human cancers. miR-124 has been widely reported in various cancers and it is intimately involved in proliferation, cell cycle regulation, apoptosis, migration, and invasion of cancer cells. The aim of this study was to explore the relationship between the miR-124/cyclin-dependent kinase 4 (CDK4) axis and the radiosensitivity of esophageal cancer cells. In this study, we identified the reduced expression of miR-124 in 18 paired esophageal cancer tissues compared to their matched normal tissues. In order to investigate the physiological role of miR-124 in esophageal cancer, the cell counting kit-8 (CCK-8) assay and wound healing assay were performed, and the results suggest that miR-124 overexpression decreases tumor growth and aggression. Next, we detected the effects of ectopic miR-124 expression on the apoptosis of an esophageal cancer cell line (TE-1) following radiotherapy. Using the CCK-8 assay and Hoechst 332528 stain, we found that ectopic expression of miR-124 led to a higher percentage of apoptotic cells. Finally, we identified that CDK4 is a direct target of miR-124 in TE-1 cells using target prediction algorithms and a luciferase reporter assay. Moreover, western blot assay confirmed that CDK4 was downregulated during miR-124 transfection. Taken together, we illustrate that the miR-124/CDK4 axis plays an important role in radiation sensitivity of human esophageal cancer cells by targeting CDK4.

Intrasplenic transplantation of IL-18 gene-modified hepatocytes: an effective approach to reverse hepatic fibrosis in schistosomiasis through induction of dominant Th1 response

Hepatic fibrosis is a common outcome of chronic liver diseases. In schistosomiasis, chronic parasite egg-induced granuloma formation can lead to fibrosis, which is immunologically characterized by the dominant Th2 response. Recently, it has been shown that gene therapy is an attractive approach for the treatment of hepatic fibrosis. To investigate the antifibrotic effects of IL-18 gene transfer, a normal murine liver cell line BNL.CL2 was transfected with recombinant adenovirus encoding mouse IL-18, and then intrasplenically transplanted into mice infected with Schistosoma japonicum (S. japonicum). Our data show that IL-18 gene-modified hepatocytes intrasplenically transplanted into mice can effectively express IL-18 in the liver and in peripheral blood. Intrasplenic transplantation of IL-18 gene-modified hepatocytes into S. japonicum-infected mice could result in a significantly increased IFN-gamma and IL-2 but decreased IL-4 and IL-10 concentration both in the liver and in the serum, suggesting that the dominant Th2 response in mice with schistosomiasis could be reversed by this intervention. Consistent with the changes in Th1 and Th2 cytokine production, mice intrasplenically transplanted with IL-18 gene-modified hepatocytes developed much less hepatic fibrosis at 20 weeks after infection, which was evaluated by liver content of hydroxyproline, collagens, and hepatic mRNA expression of procollagens. These data indicate that intrasplenic transplantation of IL-18 gene-modified hepatocytes can be a candidate for therapeutic intervention in hepatic fibrosis through induction of a dominant Th1 response.

Integrating metallic nanoparticles of Au and Pt with MoS2–CdS hybrids for high-efficient photocatalytic hydrogen generation via plasmon-induced electron and energy transfer

A mechanism of high-efficient photocatalytic hydrogen generation via plasmon-induced electron and energy transfer was demonstrated.

Solution-dispersible Au nanocube dimers with greatly enhanced two-photon luminescence and SERS

We report the synthesis of 43-nm diameter Au nanocube dimers by using Ag(+) ions as competitive ligands to freeze L-cysteine-induced assembly process of the nanocubes to a desirable stage. Ascribed to the resonant interparticle coupling with an newly arising plasmon band at 710 nm and local field enhancement, the two-photon luminescence intensity of the Au nanocube dimers in solution was over 20 times stronger than that of the monomers in the wavelength range 555-620 nm. Furthermore, by coupling Raman tags onto the nanocube surface, a solution-based surface-enhanced Raman scattering (SERS) of the nanocube dimers had an enhancement factor of over 10 times compared to the isolated nanocubes. To sum up, with high stability in solution and attractive optical properties, the Au nanocube dimers have potential applications in in vivo bio-imaging and solution-based SERS.