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Brain tumor is one of the most lethal cancers owing to the existence of blood-brain barrier and blood-brain tumor barrier as well as the lack of highly effective brain tumor treatment paradigms. Herein, cyclo(Arg-Gly-Asp-D-Phe-Lys(mpa)) decorated biocompatible and photostable conjugated polymer nanoparticles with strong absorption in the second near-infrared (NIR-II) window are developed for precise photoacoustic imaging and spatiotemporal photothermal therapy of brain tumor through scalp and skull. Evidenced by the higher efficiency to penetrate scalp and skull for 1064 nm laser as compared to common 808 nm laser, NIR-II brain-tumor photothermal therapy is highly effective. In addition, via a real-time photoacoustic imaging system, the nanoparticles assist clear pinpointing of glioma at a depth of almost 3 mm through scalp and skull with an ultrahigh signal-to-background ratio of 90. After spatiotemporal photothermal treatment, the tumor progression is effectively inhibited and the survival spans of mice are significantly extended. This study demonstrates that NIR-II conjugated polymer nanoparticles are promising for precise imaging and treatment of brain tumors.

A method has been developed for the rapid determination of calf thymus (ct) DNA that is based on the photoinduced electron transfer (PET) that occurs between CdTe quantum dots and the ruthenium(II)tris-bipyridyl complex. The latter quenches the photoluminescence (PL) of the quantum dots through PET. The Stern-Volmer quenching constant is 2,500 L mol−1. The intensity of the PL the system is recovered in the presence of ct DNA, and relative recovered PL intensity is linearly proportional to the concentration of ct-DNA. The dynamic range is from 17 µM to 1.5 mM of DNA, and the detection limit (at S/N = 3) is 5.7 µM. The relative standard deviation (at 0.5 mM of ct-DNA) is 4.1% (n = 11). A possible reaction mechanism is discussed.

The blood brain barrier is the main obstacle to delivering diagnostic and therapeutic agents to the diseased sites of brain. It is still of great challenge for the combined use of focused ultrasound (FUS) and theranostic nanotechnology to achieve noninvasive and localized delivery of chemotherapeutic drugs into orthotopic brain tumor. In this work, a unique theranostic nanoplatform for highly efficient photoacoustic imaging‐guided chemotherapy of brain tumor both in vitro and in vivo, which is based on the utilization of hollow mesoporous organosilica nanoparticles (HMONs) to integrate ultrasmall Cu2− xSe particles on the surface and doxorubicin inside the hollow interior, is synthesized. The developed multifunctional theranostic nanosystems exhibit tumor‐triggered programmed destruction due to the reducing microenvironment‐responsive cleavage of disulfide bonds that are incorporated into the framework of HMONs and linked between HMONs and Cu2− xSe, resulting in tumor‐specific biodegradation and on‐demand drug‐releasing behavior. Such tumor microenvironment‐responsive biodegradable and biocompatible theranostic nanosystems in combination with FUS provide a promising delivery nanoplatform with high performance for orthotopic brain tumor imaging and therapy.

Selective determination of Ag(I) ion was accomplished based on the red-shift of the emission band of quantum dots (QDs). Under optimal conditions, a linear relationship does exist between the red-shift of the emission and the concentration of Ag(I) in the range from 1.0 × 10−7 to 1.5 × 10−5 mol L−1, with a detection limit of 5.0 × 10−8 mol L−1. The method has been successfully applied to the determination of Ag(I) ion in water samples. The possible reaction mechanism was investigated by ultraviolet–visible absorption, fluorescence, Raman spectroscopies and by high resolution transmission electron microscopy. The results suggest that the red-shift in emission be attributed to the stabilization of a charge-transfer state, but not due to the aggregation induced by AgI(I) ion.

In this paper, the electrogenerated chemiluminescence (ECL) from thiol-capped CdTe quantum dots (QDs) was reported. The ECL emission was occurred at −1.1 V and reached a maximum value at −2.4 V when the potential was cycled between 0.0 and −2.5 V. The reduced species of CdTe QDs could react with the coreactants to produce the ECL emission. The CdTe QD concentration (6.64 × 10 −7 mol L −1 ) of ECL is lower than that (1.0 × 10 −3 mol L −1 ) of chemiluminescence (CL). Based on the enhancement of light emission from thiol-capped CdTe QDs by H 2 O 2 in the negative electrode potential, a novel method for the determination of H 2 O 2 was developed. The light intensity was linearly proportional to the concentration of H 2 O 2 between 2.0 × 10 −7 and 1.0 × 10 −5 mol L −1 with a detection limit of 6.0 × 10 −8 mol L −1 . Compared with most of previous reports, the proposed method has higher sensitivity for the determination of H 2 O 2 . In addition, the ECL spectrum of thiol-capped CdTe QDs exhibited a peak at around 620 nm, which was substantially red shifted from the photoluminescence (PL) spectrum, suggesting the surface states play an important role in this ECL process.

The interaction of water-soluble CdSe quantum dots (QDs) with gold (Au) nanoparticles was investigated by ultraviolet visible absorption spectroscopy. The results showed that the aggregation of Au nanoparticles was induced by CdSe QDs. The influences of factors such as the size of Au nanoparticles, acidity, buffer concentration and the concentration ratio of the CdSe QDs to Au nanoparticles were each investigated. The comparison of two different particle sizes (16 and 25 nm) of Au nanoparticles that interact with CdSe QDs in the solution showed that the aggregation of small Au nanoparticles (16 nm) is easier than that of big Au nanoparticles (25 nm). At pH 7.0 phosphate buffer solution (0.02 M), the optimal molar ratio of CdSe:Au is about 3100:1 according to calculations.

A chelator-free doping method is developed for constructing a Ni-integrated CuS nanostructure as a novel PA/MRI contrast agent. It exhibits tunable near-infrared absorption. Moreover, the hybrid nanostructure has demonstrated a dramatically enhanced T1 relaxivity compared with Ni ions. Due to these unique properties, chelator-free nanoparticles have been successfully applied for in vivo PA/MRI dual-modal imaging.

Smart nanoparticles (NPs) that respond to external and internal stimulations have been developing to achieve optimal drug release in tumour. However, applying these smart NPs to attain high antitumour performance is hampered by limited drug carriers and inefficient spatiotemporal control. Here we report a noninvasive NIR-driven, temperature-sensitive DI-TSL (DOX/ICG-loaded temperature sensitive liposomes) co-encapsulating doxorubicin (DOX) and indocyanine green (ICG). This theranostic system applies thermo-responsive lipid to controllably release drug, utilizes the fluorescence (FL) of DOX/ICG to real-time trace the distribution of NPs and employs DOX/ICG to treat cancer by chemo/photothermal therapy. DI-TSL exhibits uniform size distribution, excellent FL/size stability, enhanced response to NIR-laser and 3 times increased drug release through laser irradiation. After endocytosis by MCF-7 breast adenocarcinoma cells, DI-TSL in cellular endosomes can cause hyperthermia through laser irradiation, then endosomes are disrupted and DI-TSL ‘opens’ to release DOX simultaneously for increased cytotoxicity. Furthermore, DI-TSL shows laser-controlled release of DOX in tumour, enhanced ICG and DOX retention by 7 times and 4 times compared with free drugs. Thermo-sensitive DI-TSL manifests high efficiency to promote cell apoptosis and completely eradicate tumour without side-effect. DI-TSL may provide a smart strategy to release drugs on demand for combinatorial cancer therapy.

A multifunctional drug delivery vehicle consisting of a tubular shaped silica host, a compact superparamagnetic iron oxide nanoparticle layer and a hyaluronic acid surface coating was developed as a theranostic platform, for in vivo MR imaging and magnetically guided/cancer targeted drug delivery.

A novel method for the preparation of water-soluble and small-size CdSe quantum dots has been reported under high-intensity ultrasonic irradiation. The as-prepared products have been characterized by absorption spectra, X-ray powder diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM).

Phototherapy, including photodynamic therapy (PDT) and photothermal therapy (PTT), is a light-activated local treatment modality that is under intensive preclinical and clinical investigations for cancer. To enhance the treatment efficiency of phototherapy and reduce the light-associated side effects, it is highly desirable to improve drug accumulation and precision guided phototherapy for efficient conversion of the absorbed light energy to reactive oxygen species (ROS) and local hyperthermia. In the present study, a programmed assembly strategy was developed for the preparation of human serum albumin (HSA)-indocyanine green (ICG) nanoparticles (HSA-ICG NPs) by intermolecular disulfide conjugations. This study indicated that HSA-ICG NPs had a high accumulation with tumor-to-normal tissue ratio of 36.12±5.12 at 24 h and a long-term retention with more than 7 days in 4T1 tumor-bearing mice, where the tumor and its margin, normal tissue were clearly identified via ICG-based in vivo near-infrared (NIR) fluorescence and photoacoustic dual-modal imaging and spectrum-resolved technology. Meanwhile, HSA-ICG NPs efficiently induced ROS and local hyperthermia simultaneously for synergetic PDT/PTT treatments under a single NIR laser irradiation. After an intravenous injection of HSA-ICG NPs followed by imaging-guided precision phototherapy (808 nm, 0.8 W/cm2 for 5 min), the tumor was completely suppressed, no tumor recurrence and treatments-induced toxicity were observed. The results suggest that HSA-ICG NPs generated by programmed assembly as smart theranostic nanoplatforms are highly potential for imaging-guided cancer phototherapy with PDT/PTT synergistic effects.

The structural, electrical transport and magnetic properties of perovskite oxides La 1− x Te x MnO 3 (0.1 ≤ x ≤ 0.6) have been investigated and thus the magnetic phase diagram of La 1− x Te x MnO 3 (0.1 ≤ x ≤ 0.6) compounds as a function of temperature and the doping level x has been obtained. All samples have rhombohedral structure and undergo paramagnetic–ferromagnetic (PM–FM) transition accompanied with metal–insulator transition (MIT). A charge ordering (CO) transition begins to appear at T CO ∼ 250 K for the sample with x = 0.60. Moreover, the variation of the Curie temperature T c and the MIT temperature T p is quite complex and the results are discussed in terms of three factors including the average A-site cation radius 〈 r A 〉, the size mismatch σ 2 and the Te content. In addition, there is an evidence for magnetoresistance (MR) at low-temperatures for all samples.

La0.8Na0.2MnO3 films were successfully fabricated via the chemical solution deposition (CSD) method on LaAlO3 and YSZ single crystal substrates. The results showed that the two samples behaved like epitaxial films. It was suggested that it was possible to fabricate highly (h 0 0)-oriented colossal magnetoresistance films on YSZ substrates using CSD.

The synthesis of water-soluble fluorescent carbon dots (C-dots) has received much attention recently. Here, high quality fluorescent C-dots have been synthesized through low-temperature carbonization and simple filtration using watermelon peel, a waste and reproducible raw resource, as a novel carbon resource. This facile approach allows large-scale production of aqueous C-dots dispersions without any post-treatment process. The as-prepared C-dots possess small particle sizes (~ 2.0 nm), strong blue luminescence, acceptable fluorescence lifetime and good stability in a wide range of pH values (pH 2.0–11.0) and at a high salt concentration. Besides, the obtained C-dots have been successfully applied in live cell imaging, indicating these carbon nanoparticles can serve as high-performance optical imaging probes.

A key challenge to strengthen anti-tumor efficacy is to improve drug accumulation in tumors through size control. To explore the biodistribution and tumor accumulation of nanoparticles, we developed indocyanine green (ICG) loaded poly (lactic-co-glycolic acid) (PLGA) -lecithin-polyethylene glycol (PEG) core-shell nanoparticles (INPs) with 39 nm, 68 nm and 116 nm via single-step nanoprecipitation. These INPs exhibited good monodispersity, excellent fluorescence and size stability, and enhanced temperature response after laser irradiation. Through cell uptake and photothermal efficiency in vitro, we demonstrated that 39 nm INPs were more easily be absorbed by pancreatic carcinoma tumor cells (BxPC-3) and showed better photothermal damage than that of 68 nm and 116 nm size of INPs. Simultaneously, the fluorescence of INPs offered a real-time imaging monitor for subcellular locating and in vivo metabolic distribution. Near-infrared imaging in vivo and photothermal therapy illustrated that 68 nm INPs showed the strongest efficiency to suppress tumor growth due to abundant accumulation in BxPC-3 xenograft tumor model. The findings revealed that a nontoxic, size-dependent, theranostic INPs model was built for in vivo cancer imaging and photothermal therapy without adverse effect.

A novel method for the synthesis of CdTe quantum dots–polystyrene (CdTe/PS) composite nanospheres was developed by a two-step route. The as-prepared composite nanospheres were characterized by high-resolution transmission electron microscopy (HRTEM), X-ray powder diffraction (XRD), fluorescent microscope imaging and fluorescence spectrometer. The results showed that the composite nanospheres were spherical and relatively uniform with a diameter of 120 nm. Compared with previous methods, the proposed method was simple, efficient and inexpensive, moreover the composite nanospheres exhibited favorable water-dispersible, stable, size-tunable and fluorescent properties.

Multimodal imaging is highly desirable for accurate diagnosis because it can provide complementary information from each imaging modality. In this study, we prepared hybrid gold–gadolinium nanoclusters (NCs), which are ultrasmall, stable, biocompatible, and suitable for triple-modal NIRF/CT/MRI imaging. Upon intravenously injected, the hybrid NCs are effectively accumulated in tumor tissues and quickly clear by renal excretion, indicating their capacity of tumor targeting and low body residues. Notably, the ultrasmall hybrid NCs would penetrate into the solid tumor for capturing its heterostructure and do not induce potential toxicity in vivo. Hence, the well-defined hybrid gold–gadolinium NCs provide a versatile nanoprobe for cancer targeted imaging and diagnosis in vivo.

Aptamers have emerged as promising molecular probes for cancer diagnosis. However, their application for in vivo cancer imaging remains limitation due to the poor stability in blood and the degradation by nucleases. In the present study, we generated PEI/aptamer molecular complexes for cancer imaging in vivo by using deoxyribonuclease (DNase)-activatable fluorescence probes (DFProbes) to monitor DNA degradation. The results showed that the complexes with PEI at the N/P ratio from 3.8 to 15 effectively prevented the degradation of DFProbes both in vitro and in vivo. Moreover, PEI successfully protected TD05 aptamers from DNase degradation without affecting its specific recognition of Ramos cells. In tumor bearing mice, PEI/aptamer molecular complexes further demonstrated superior passive tumor targeting and extended circulation time as compared with free aptamer. Hence, the well-defined PEI/aptamer probe is a novel strategy to deliver targeted aptamer for tumor diagnosis and imaging in vivo.

Indocyanine green (ICG) is a near-infrared (NIR) fluorescence dye for extensive biological application, but limited by its poor aqueous stability in vitro, concentration-dependent aggregation, rapid elimination from the body, and lack of target specificity. In this paper, to overcome these limitations, folate receptor-targeted, ICG dye-doped poly(d,l-lactide-co-glycolide) (PLGA) lipid nanoparticles (FA-ICG-PLGA-lipid NPs) were constructed by a single-step self-assemble and nanoprecipitation method. The prepared FA-ICG-PLGA-lipid NPs exhibited good biocompatibility, monodispersity, excellent NIR penetration ability, significant stability against photobleaching and long circulation time. The intracellular uptake experiment proved the targeting efficacy of the FA-ICG-PLGA-lipid NPs was more effective in folate receptor over-expressing MCF-7 cells than folate receptor negative A549 cells. Furthermore, the in vivo experiments showed the FA-ICG-PLGA-lipid NPs were specifically targeted to the tumor, and its circulation time was much longer than free ICG. These biocompatible and biodegradable NIR-NPs prove a potential application in tumor diagnosis and targeted imaging due to its high aqueous stability, excellent NIR optical properties and significantly targeting property in vivo.

Porcine circovirus type 2 (PCV2) is associated with many diseases especially postweaning multisystemic wasting syndrome (PMWS), which has brought huge economic loss to the swine industry worldwide. Viral detection will pave the way for this disease prevention. Herein, we developed a facile, rapid and ultrasensitive method for detection of PCV2 based on gold(III) enhanced chemiluminescence immunoassay (CLIA). The gold(III), dissolved from the gold nanoparticle-monoclonal antibody conjugate, served as an analyte for the indirect measurement of PCV2. Under the optimal conditions, the detection limit for the detection of PCV2 was 1.71 x 10(3) copies mL(-1). Moreover, the CLIA signal can be further enhanced by using hydroxylamine-amplified gold nanoparticles, and the limit of detection was as low as 2.67 x 10(2) copies mL(-1). Compared with conventional polymerase chain reaction (PCR), the proposed method has good sensitivity and reliability in analysis of 36 serum samples, and showed great potential in virus assays.

In this paper, we report a new homogeneous assay for rapid, highly selective and sensitive detection of Hg(2+) in aqueous solution based on the induced photoluminescence (PL) quenching of BSA-modified gold nanoclusters (BSA-Au NCs). There was a linear correlation between the expression (I(0)- I)/I(0) and the concentrations of Hg(2+) over the ranges of 0.4-43.2 microM, and the corresponding limit of detection (LOD) was 80 nM. The relative standard deviation of 5 replicate measurements was 1.4% for 1.0 x 10(-5) mol L(-1) Hg(2+). Moreover, this method has excellent selectivity over metal ions and anions. The feasibility of the BSA-Au NCs sensor for Hg(2+) in different aqueous samples was demonstrated with satisfactory results. Moreover, the possible sensing Hg(2+) mechanism was also discussed.

A novel method for the detection of hydrogen peroxide (H(2)O(2)) has been developed, based on electrogenerated chemiluminescence (ECL) of blue emitting ZnSe quantum dots (QDs) in aqueous solution. The weak ECL emission of ZnSe QDs was generated when the electrode potential was scanned from 0.0 to -1.4V (versus Ag/AgCl), and the ECL intensity was greatly enhanced in the presence of H(2)O(2) or dissolved oxygen. Under the optimal conditions, the dynamic range is from 6.10 x 10(-7) to 3.10 x 10(-4)M H(2)O(2), and the detection limit (at S/N=3) is 2.00 x 10(-7)M. The relative standard deviation (at 5.00 x 10(-5)M of H(2)O(2)) is 2.70% (n=11). A possible reaction mechanism of ECL of ZnSe QDs was also investigated. As a novel biosensor, it was used to detect H(2)O(2) in the pig kidney (pk-15) cell, vero cell and mineral water, respectively. Moreover, the proposed biosensor showed a good reproducibility and potential application in real samples.

Here we report a indirect fluorescence immunoassay for high-throughput screening of APP based on the fluorescence quenching of quantum dots by gold(III), which were dissolved from gold nanoparticles-Rabbit anti-Pig IgG conjugate, and further utilize this system to detect APP in pig serum with high sensitivity and specificity.

Based on the inhibition effect of methimazole (MMI) on the reaction of luminol–H2O2 catalyzed by gold nanoparticles, a novel chemiluminescence (CL) method was developed for the determination of MMI. Under the optimum conditions, the relative CL intensity was linearly related to MMI concentration in the range from 5.0 × 10−8 to 5.0 × 10−5 mol L−1. The detection limit was 1.6 × 10−8 mol L−1 (S/N = 3), and the RSD for 6.0 × 10−6 mol L−1 MMI was 4.83 (n = 11). This method has high sensitivity, wide linear range, inexpensive instrumentation and has been applied to detect MMI in pharmaceutical tablets and pig serum samples. Furthermore, a possible reaction mechanism is discussed. Copyright © 2010 John Wiley & Sons, Ltd.

The effect of $\mathrm{Cu}$-doping at $\mathrm{Mn}$-site on structural, magnetic and transport properties in electron-doped manganites ${\mathrm{La}}_{0.85}{\mathrm{Te}}_{0.15}{\mathrm{Mn}}_{1\ensuremath{-}x}{\mathrm{Cu}}_{x}{\mathrm{O}}_{3}$ $(0\ensuremath{\leqslant}x\ensuremath{\leqslant}0.20)$ has been investigated. Based on the analysis of structural parameter variations, the valence state of the $\mathrm{Cu}$ ion in $\mathrm{Cu}$-doped manganites is suggested to be $+2$. All samples undergo the paramagnetic-ferromagnetic (PM-FM) phase transition. The Curie temperature ${T}_{c}$ decreases and the transition becomes broader with increasing $\mathrm{Cu}$-doping level, in contrast, the magnetization magnitude of $\mathrm{Cu}$-doping samples at low temperatures increase as $x\ensuremath{\leqslant}0.15$. The insulator-metal (I-M) transition moves to lower temperatures with increasing $\mathrm{Cu}$-doping content and disappears as $xg0.1$. In addition, the higher temperature resistivity $\ensuremath{\rho}$ peak in double-peak-like $\ensuremath{\rho}(T)$ curves observed in no $\mathrm{Cu}$-doping sample is completely suppressed as $\mathrm{Cu}$-doping level $x=0.1$ and $\ensuremath{\rho}(T)$ curve only shows single I-M transition at the low temperature well below ${T}_{C}$. The results are discussed according to the change of magnetic exchange interaction caused by $\mathrm{Cu}$-doping.

The effect of grain size on structural, magnetic and transport properties in electron-doped manganites La0.9Te0.1MnO3 has been investigated. All samples show a rhombohedral structure with the space group at room temperature. It shows that the Mn-O-Mn bond angle decreases and the Mn-O bond length increases with the increase of grain size. All samples undergo paramagnetic (PM)-ferromagnetic (FM) phase transition and an interesting phenomenon that both magnetization and the Curie temperature decrease with increasing grain size is observed, which is suggested to mainly originate from the increase of the Mn-O bond length . Additionally, obviously increases with decreasing grain size due to the increase of both the height and width of tunneling barriers with decreasing the grain size. The results indicate that both the intrinsic colossal magnetoresistance (CMR) and the extrinsic the extrinsic interfacial magnetoresistance (IMR) can be effectively tuned in La0.9Te0.1MnO3 by changing grain size., 15 pages,4 figures. Solid state communications 132(2004)83-87

We developed a facile one-step method to produce ready-to-use quantum dots based on a peptide sequence containing a hexahistidine(his6-tag), poly(ethylene glycol) (PEG), and a functional group, which lead to stable and customized peptide-QDs conjugates that could serve as fluorescent nanoprobes for biological imaging and detection.

Fluorescence signal amplification by cation exchange in aptamer-conjugated CdSe nanoclusters, a biological self-assembly of CdSe quantum dots, was developed as a novel method for cancer cell detection.

A simple, rapid, cost-efficient and convenient method has been developed for synthesis of water-soluble CdTe quantum dots (QDs) under ambient atmospheric conditions. Using this method, the preparation of Te precursor and growth of CdTe QDs were achieved with one-step synthetic route. Under the optimal conditions, the as-prepared CdTe QDs possessed a high photoluminescence quantum yield (84%), a narrow size distribution (full width at half maximum = 30 nm), small particle size (2.6 nm) and low cytotoxicity. The photoluminescence and electrogenerated chemiluminescence (ECL) behaviors of as-prepared CdTe QDs show their potential application in cell imaging and ECL biosensing with high sensitivity.

Electrogenerated chemiluminescence (ECL) of CdSe quantum dots (QDs) dispersed in aqueous solution was studied with bare electrode. The ECL emission was observed at -1.4 V vs. Ag/AgCl and the ECL spectrum peak is similar to that of the defect photoluminescence (PL) spectrum, indicating the surface defects played a critical role in the emission process. The experiment results suggested that dissolved oxygen had a great effect on the ECL intensity. Other influence factors including the electrochemical parameters and QDs concentration were investigated in detail. As an application of the CdSe QDs ECL, the pyrogallol (1, 2, 3-trihydroxybenzene) was detected in aqueous solution. Under the optimal conditions, a linear relationship between ECL intensity and pyrogallol concentration was obtained in the range from 4.0 x 10(-7) to 2.0 x 10(-5) M with a correlation coefficient of 0.9904 and the limit of detection was 6.6 x 10(-8) M (S/N = 3). A possible mechanism about ECL of QDs was also discussed.