[Show abstract][Hide abstract] ABSTRACT: Background
Tumor-target fluorescence bioimaging is an important means of early diagnosis, metal nanoclusters have been used as an excellent fluorescent probe for marking tumor cells due to their targeted absorption. We have developed a new strategy for facile synthesis of Au/Ce nanoclusters (NCs) by doping trivalent cerium ion into seed crystal growth process of gold. Au/Ce NCs have bright fluorescence which could be used as fluorescent probe for bioimaging.ResultsIn this study, we synthesized fluorescent Au/Ce NCs through two-step hydrothermal reaction. The concentration range of 25¿350 ¿M, Au/Ce NCs have no obvious cell cytotoxicity effect on HeLa, HepG2 and L02 cells. Furthermore, normal cells (L02) have no obvious absorption of Au/Ce NCs. Characterization of synthesized Au/Ce NCs was done by using TEM, EDS and XPS. Then these prepared Au/Ce NCs were applied for in vitro / in vivo tumor-target bioimaging due to its prolonged fluorescence lifetime and bright luminescence properties.Conclusions
The glutathione stabilized Au/Ce NCs synthesized through hydrothermal reaction possess stable and bright fluorescence that can be readily utilized for high sensitive fluorescence probe. Our results suggest that Au/Ce NCs are useful candidate for in vitro / in vivo tumor bioimaging in potential clinical application.
[Show abstract][Hide abstract] ABSTRACT: Novel ferrocenyl based carboranes (FcCBs) and their distinguish behavior for cancer cell recognition have been explored in this contribution. The voltammetric study in a droplet of 10 μL placed on the surface of a glassy carbon electrode demonstrates the excellent electrochemical behavior of FcCBs, which could be further exploited for establishing the promising and sensitive biosensors. The FcCBs’ redox behavior is examined in a wide pH range, and square wave voltammetry revealed the reversible and irreversible nature of first and second anodic peaks. The obvious shifts in peak potentials corresponding with the change of pH values demonstrate the abstraction of electrons to be accompanied with the transfer of protons. By using the droplet electrochemical technique, FcCBs can be employed to distinguish normal and cancer cells with a linear range from 1.0 × 103 to 3.0 × 104 cells mL−1 and the limit of detection at 800 cells mL−1. The novel carborane derivatives could be utilized as important potential molecular probes for specific recognition of cancer cells like leukemia cells from normal cells.
[Show abstract][Hide abstract] ABSTRACT: In this study, we have developed a label-free, dual functional detection strategy for highly selective and sensitive determination of aqueous Ag+ and Hg2+ by using cytidine stabilized Au NCs and AuAg NCs as fluorescent turn-on and turn off probes, respectively. The Au NCs and AuAg NCs showed a remarkably rapid response and high selectivity for Ag+ and Hg2+ over other metal ions, and relevant detection limit of Ag+ and Hg2+ is ca. 10 nM and 30 nM, respectively. Importantly, the fluorescence enhanced Au NCs by doping Ag+ can be conveniently reusable for the detection of Hg2+ based on the corresponding fluorescence quenching. The sensing mechanism was based on the high-affinity metallophilic Hg2+-Ag+ interaction, which effectively quenched the fluorescence of AuAg NCs. Furthermore, these fluorescent nanoprobes could be readily applied to Ag+ and Hg2+ detection in environmental water samples, indicating their possibility to be utilized as a convenient, dual functional, rapid response, and label-free fluorescence sensor for related environmental and health monitoring.
[Show abstract][Hide abstract] ABSTRACT: A sensitive hydrogen peroxide (H2O2) sensor was constructed based on graphene-Pt (RGO-Pt) nanocomposites and used to measure the release of H2O2 from living cells. The graphene and Pt nanoparticles (Pt NPs) were modified on glassy carbon electrode (GCE) by the physical adsorption and electrodeposition of K2PtCl6 solution, respectively. Through characterization by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS), it was observed that the electrodeposited Pt NPs were densely covered and well distributed on the entire graphene surface. Electrochemical study demonstrates that the RGO-Pt nanocomposites modified glassy carbon electrode exhibited a high peak current and low overpotential toward the reduction of H2O2. The relevant detection limit of H2O2 is ∼0.2 μM with a wide linear range from 0.5 μM to 3.475 mM, displaying a much higher sensitivity (459 ± 3 mA M(-1) cm(-2), n = 5) than that of Pt nanoparticles or graphene modified electrode. This novel biosensor can measure the H2O2 release from living cells because of its low detection limit, wide linear range, and higher sensitivity.
[Show abstract][Hide abstract] ABSTRACT: Fluorescent gold/silver nanoclusters templated by DNA or oligonucleotides have been widely reported, since DNA or oligonucleotides could be designed to position a few metal ions at close proximity prior to their reduction, but nucleoside-templated synthesis is more challenging. In this work, a novel type of strategy taking cytidine (C) as template to rapid synthesis of fluorescent, water-soluble gold and silver nanoclusters (C-AuAg NCs) has been developed. The as-prepared C-AuAg NCs have been characterized by UV-Vis absorption spectroscopy, fluorescence, transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR) and inductively coupled plasma-mass spectroscopy (ICP-MS). The characterizations demonstrate that C-AuAg NCs with a diameter of 1.50 ± 0.31 nm, a quantum yield ~ 9% and an average lifetime ~ 6.07 µs possess prominent fluorescence properties, good dispersibility and easy water solubility, indicating the promising application in bioanalysis and biomedical diagnosis. Furthermore, this strategy by rapid producing of highly fluorescent nanoclusters could be explored for the possible recognition of some disease related changes in blood serum. This raises the possibility of their promising application in bioanalysis and biomedical diagnosis.
[Show abstract][Hide abstract] ABSTRACT: Simultaneous and multisite tumor rapid-target bioimaging has been realized in this contribution through in vivo biosynthesis of fluorescent gold nanoclusters (GNCs). The selectively biosynthesized fluorescent GNCs in cancer cells or tumor tissues by systemic bio-administration of gold precursors via tail vein injection in tumor bearing mice were found to exhibit a highly efficient tumor targeting effect. Intracellular fluorescence studies demonstrate that in vivo biosynthesized GNCs from cancer cells could efficiently label and image target cells with bright photostable fluorescence, which could be readily exploited for the rapid imaging in vivo of the biodistribution of GNCs in mice and thus efficiently determine the precise target sites of fluorescent GNCs specifically biosynthesized in tumor tissues with high spatiotemporal resolution. Moreover, histopathologic analyses of H&E-stained tissue sections indicate that no side effects for mice treated with gold precursors are found during the process of systemic bio-administration for gold precursors. This raises the possibility of utilizing the in vivo biosynthesized GNCs through intravenous administration of biocompatible gold precursors as promising and effective biomarkers for rapid tumor diagnosis and precise surgical intervention.
[Show abstract][Hide abstract] ABSTRACT: Fluorescent platinum nanoclusters constructed through one-step synthesis from chloroplatinic acid cross swiftly across carcinoma cell membranes for bio-imaging and photothermal treatment.
[Show abstract][Hide abstract] ABSTRACT: Ultra-small metallic nanoparticles, or so-called "nanoclusters" (NCs), have attracted considerable interest due to their unique optical properties that are different from both larger nanoparticles and single atoms. To prepare high-quality NCs, the stabilizing agent plays an essential role. In this work, we have revealed and validated that cytidine and its nucleotides (cytidine 5'-monophosphate or cytidine 5'-triphosphate) can act as efficient stabilizers for syntheses of multicolored Au NCs. Interestingly, Au NCs with blue, green and yellow fluorescence emissions are simultaneously obtained using various pH environments or reaction times. The transmission electron microscopy verifies that the size of Au NCs ranges from 1.5 to 3 nm. The X-ray photoelectron spectroscopy confirms that only Au (0) species are present in NCs. Generally, the facile preparation of multicolored Au NCs that are stabilized by cytidine units provides access to promising candidates for multiple biolabeling applications.
[Show abstract][Hide abstract] ABSTRACT: Rapid and ultrasensitive detection of pathogenic bacteria and their relevant multidrug resistance is particularly important in clinical diagnosis, disease control, and environmental monitoring. In this contribution, we have explored the possibility to rapidly detect some important disease related bacteria based on nanostructured Au modified ITO electrode through the antibiotic agents such as doxorubicin (DOX). The rapid and real-time electrochemical detection of multidrug resistant bacteria like E. coli and S. aureus could be readily realized through the nanostructured Au based biosensor with high sensitivity. The observations of surface-enhanced Raman spectroscopy and laser confocal fluorescence microscopy also demonstrate the effectiveness of the relevant new strategy for the rapid and ultrasensitive electrochemical detection of some disease related bacteria.
[Show abstract][Hide abstract] ABSTRACT: As one of the active compounds derived from Traditional Chinese Medicine, Celastrol (CSL) had cytotoxicity for human leukemia cancer cells K562 and its multidrug-resistant cell line K562/A02. Here, we introduced cysteamine-modified CdTe QDs as the labeling and drug carrier into CSL research and found that the self-assembly and conjugation of anticancer molecular CSL with the Cys-CdTe QDs could significantly increase the drug’s cytotoxicity for K562 cells. More important, these CSL-Cys-CdTe nanocomposites could overcome the multidrug resistance of K562/A02 cells and efficiently inhibit the cancer cell proliferation by realizing the pH-sensitive responsive release of CSL to cancer cells. The enhanced cytotoxicity was caused by the increase of the G2/M phase arrest for K562/A02 cells as well as for K562 cells. Cys-CdTe QDs can readily bind on the cell plasma membranes and be internalized into cancer cells to trace and detect human leukemia cancer cells in real time. In addition, these Cys-CdTe QDs can facilitate the inhibition of the multidrug resistance of K562/A02 cells and readily induce apoptosis. As a good photosensitizer for the therapy, labeling, and tracing of cancer cells, the combination of CSL with Cys-CdTe QDs can optimize the use of and a new potential therapy method for CSL and yield new tools to explore the mechanisms of active compounds from Traditional Chinese Medicine.
[Show abstract][Hide abstract] ABSTRACT: Human life toll by cancer, one of the highest among most dreaded diseases in advanced societies, could be reduced by implementing evidence-based strategies for its prevention, early diagnosis and assessment of the progress and suitability of therapies by fast and non-invasive methods. In this contribution, a novel strategy is reported for highly sensitive recognition and in vivo imaging of cancer cells taking advantage of their spontaneous ability to generate silver nanoclusters (NCs) with high near-infrared fluorescence emission by intracellular reduction of innocuous silver salts. Both ex vivo experiments comparing cancer cell models to normal cells and in vivo imaging of subcutaneous xenografted tumor (cervical carcinoma model) in nude mice established the validity of this strategy for precise and selective imaging of cells and tumors. Furthermore, it was observed that the spontaneous self-generation of Ag NCs by tumors in their inside led to drastic reduction of their sizes and often to complete remission, thus providing important hope for new therapy strategies based on cheap and readily available agents.
[Show abstract][Hide abstract] ABSTRACT: During photodynamic therapy (PDT) of cancers, there are numerous side effects, accompanied by damage to normal cells/tissues caused by the abnormal elevation of reactive oxygen species (ROS). In this paper, we aim to provide an effective method to reduce the relevant side effects of PDT by using cerium oxide nanoparticles. The well-dispersed poly(vinyl pyrrolidone) stabilized cerium oxide nanoparticles were successfully synthesized by using a one-pot method at 60 degrees C in slightly alkaline environment. The morphological and structural characterizations clearly illustrate the excellent lattice structures of cerium oxide, nanoparticles. The MTT assay indicates that these cerium oxide nanoparticles show no intrinsic cytotoxicity even at a concentration up to 300 micro g/mL. More importantly, the results demonstrate that these nanoparticles can selectively protect human normal cells but not the cancer cells from ROS damage after exposure to UV-radiation, suggesting their potential applications for PDT treatment. The rationale behind the selective protection effect can be attributed to the hindrance of the Ce (III)/Ce (IV) redox reaction cycle on the surface of cerium oxide nanoparticles due to the abnormal intracellular pH in cancer cells. Furthermore, these cerium oxide nanoparticles can be used as effective drug carriers for enhancing drug delivery efficiency to target cancer cells like hepatoma HepG2 cells. This raises the possibility of applying cerium oxide nanoparticles for multifunctional therapeutic applications, i.e., combination of efficient PDT and chemotherapy.
Journal of Biomedical Nanotechnology 02/2014; 10(2):278-86. · 7.58 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Magnetic nanospheres have recently attracted much attention in the biomedical areas due to their good biocompatibility and unique magnetic features. Herein we report the synthesis and characterization of different sized porous superparamagnetic iron oxide nanospheres (SPIONs) (Zn1/3Fe8/3O4) which are based on a new rational method of elevated-temperature hydrolysis of chelate iron alkoxide complexes in solutions of the corresponding alcohol, diethyleneglycol (DEG) and diethanolamine (DEA). The size of the SPIONs is controlled by changing the ratio of the reaction media. It is noted that the highly water dispersible porous SPIONs with narrow size distribution can be tuned from 6.5 to 200 nm, each of which is composed of many single magnetite crystallites of approximately 5.5 nm in size. The SPIONs show superparamagnetic properties at room temperature. The superparamagnetic behavior, high magnetization, and high water dispersibility make these nanospheres ideal candidates for various important applications for drug delivery.
[Show abstract][Hide abstract] ABSTRACT: Recently, a growing amount of attention has been focused on the utility of biosensors for biomedical applications. Combined with nanomaterials and nanostructures, nano-scaled biosensors are installed for biomedical applications, such as pathogenic bacteria monitoring, virus recognition, disease biomarker detection, among others. These nano-biosensors offer a number of advantages and in many respects are ideally suited to biomedical applications, which could be made as extremely flexible devices, allowing biomedical analysis with speediness, excellent selectivity and high sensitivity. This minireview discusses the literature published in the latest years on the advances in biomedical applications of nano-scaled biosensors for disease bio-marking and detection, especially in bio-imaging and the diagnosis of pathological cells and viruses, monitoring pathogenic bacteria, thus providing insight into the future prospects of biosensors in relevant clinical applications.
[Show abstract][Hide abstract] ABSTRACT: The interactions between methylamine or acetic acid with the Ni(n) (n = 1,...,6) in triplet clusters were examined at the B3LYP/6-31G(d, p) and LANL2TZ+ level. The structural stability, interacting strength and the charge transferring properties of the different interacting complexes were studied. The stable distance between the Ni(1) and the nitrogen or oxygen is about 2.00 or 1.95 angstroms for the Ni(n)-CH3NH2 or Ni(n)-CH3COOH, respectively. The results indicate that the interacting energy is -27.385 approximatley -134.269 and -18.379 approximately -55.136 kJ/mol for the Ni(n)-CH3NH2 and Ni(n)-CH3COOH, respectively. The effective electron transfer processes for the Ni(n)-CH3NH2 or Ni(n)-CH3COOH is from the lone pair of the nitrogen to the lone pair anti-bonding orbital of the Ni(1) or from the oxygen lone pair to the sigma antibonding orbitals of Ni(1)-Ni and the sigma anti-bonding orbital of the Ni(1) lone pair, respectively.
Journal of Nanoscience and Nanotechnology 06/2013; 13(6):4223-7. · 1.34 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We have studied the multifunctional effects of cysteamine-coated cadmium–tellurium quantum dots (Cys–CdTe QDs) conjugated with gambogic acid (GA) for cancer cell labeling and cancer treatment. Our results indicated that the Cys–CdTe QDs (about 3 nm) could readily bind on the cell plasma membranes and then be internalized into cancer cells for real-time tracing and treatment of human leukemia cancers. The positively charged surface of the self-assembled and conjugated GA with the Cys–CdTe QDs could significantly enhance the drug accumulation into leukemia K562 cells and the drug's cytotoxicity, to inhibit the cancer cell proliferation. The GA–Cys–CdTe nanocomposites improved the drug action to overcome the multidrug resistance of K562/A02 cells and facilitated the GA induced G0/G1 phase cancer cell cycle arrest to promote cell apoptosis. Moreover, the sensitive pH-triggered release behavior of the relevant nanocomposites, loaded with GA, greatly reduced the side effects of the anticancer agents to the normal cells/tissues in the blood circulation and facilitated an efficient drug release and accumulation in the target tumor cells. Thus, the combination of an active compound from Traditional Chinese Medicine (TCM), GA, with Cys–CdTe QDs can afford a new strategy for the potential multimode cancer therapy.
[Show abstract][Hide abstract] ABSTRACT: As a novel strategy to combat the nosocomial infection caused by multidrug-resistant (MDR) bacteria like Acinetobacter baumannii, the antibacterial effect of a pair of geometrical isomers ferrocene-carborane derivatives (designated as FcSB1 and FcSB2) combining with nanoscaled titania (nano TiO2) against five MDR A. baumannii strains were explored in this contribution. The drug interaction assay and time-kill studies demonstrate the considerable enhancement effect of the TiO2 nanoparticles on the antibacterial activity of FcSB1/or FcSB2 against clinically MDR-resistant A. baumannii. Meanwhile, the relevant antibacterial efficiency assessed by a nonparametric approach (fractional inhibitory concentration [FIC] index model) illustrates that the FIC index values ranged from 0.375 to 0.106 for the combination of FcSB1 and nano TiO2, and 0.250 to 0.083 for that of FcSB2 with nano TiO2, indicating the synergistic antibacterial activity of FcSB1/or FcSB2 with nano TiO2 on target bacteria. This might shed light on the promising bio-application of these new carborane derivatives in combination with nano TiO2 to combat the nosocomial infection caused by multidrug-resistant (MDR) bacteria including A. baumannii.
Journal of Biomedical Nanotechnology 03/2013; 9(3):393-402. · 7.58 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Fluorescence imaging in vivo allows non-invasive tumor diagnostic thus permitting a direct monitoring of cancer therapies progresses. It is established herein that fluorescent gold nanoclusters are spontaneously biosynthesized by cancerous cell (i.e., HepG2, human hepatocarcinoma cell line; K562, leukemia cell line) incubated with micromolar chloroauric acid solutions, a biocompatible molecular Au(III) species. Gold nanoparticles form by Au(III) reduction inside cells cytoplasms and ultimately concentrate around their nucleoli, thus affording precise cell imaging. Importantly, this does not occur in non-cancerous cells, as evidenced with human embryo liver cells (L02) used as controls. This dichotomy is exploited for a new strategy for in vivo self-bio-imaging of tumors. Subcutaneous injections of millimolar chloroauric acid solution near xenograft tumors of the nude mouse model of hepatocellular carcinoma or chronic myeloid leukemia led to efficient biosynthesis of fluorescent gold nanoclusters without significant dissemination to the surrounding normal tissues, hence allowing specific fluorescent self-bio-marking of the tumors.
[Show abstract][Hide abstract] ABSTRACT: Daunorubicin (DNR) loaded graphene–gold nanocomposites offer a novel strategy for inducing apoptosis in drug resistant leukemia cells (K562/A02; KA). In vitro and in vivo investigations on xenografted tumors in KA nude mice demonstrate that the combination of monoclonal P-glycoprotein (P-gp) antibodies and DNR anticancer drug loaded on graphene–gold nanocomposites (GGN) is an efficient drug delivery vector, with remarkable targeting and binding properties towards drug resistant KA cell lines, and induces apoptosis of KA cells and inhibits tumor growth in KA nude mice. Cellular treatment with DNR-loaded GGN remarkably reduced drug resistant-related P-gp expression and activated apoptosis-related caspase protein expression in KA cells. Cell apoptosis provoked in vitro by such nanocomposites corresponds to a rapid induction of active caspase 8,3 activities and stimulation of poly-(ADP-ribose) polymerase (PARP) proteolytic cleavage. In vivo studies indicate that DNR-loaded GGN nanocomposites effectively overcome the inhibition of drug resistant leukemia cell-induced tumor growth in KA nude mice. This nanocomposite raises the possibility of modulating apoptosis in cancer cells, and of inhibiting tumor growth, showing that nanocomposites of this kind have promising applications in efficient multifunctional therapy.
[Show abstract][Hide abstract] ABSTRACT: Multidrug resistance (MDR) of bacteria is still an unsolved serious problem to threaten the health of human beings. Developing new antibacterial agents, therefore, are urgently needed. Herein, we have explored the possibility to design and synthesize some novel antibacterial agents including ferrocene-substituted carborane derivative (Fc(2)SBCp(1)) and have evaluated the relevant antibacterial action against two clinical common MDR pathogens (i.e., Gram-positive Staphylococcus aureus and Gram-negative Pseudomonas aeruginosa) in vitro and in vivo. The results demonstrate that in vitro antimicrobial activity of Fc(2)SBCp(1) could be gradually transformed into a bactericidal effect from a bacteriostatic effect with the increasing concentration of the active carborane derivative, which can also prevent biofilm formation at concentrations below MIC (i.e., minimal inhibitory concentration). Biocompatibility studies indicate that there exists no/or little toxic effect of Fc(2)SBCp(1) on normal cells/tissues and leads to little hemolysis. In vivo studies illustrate that the new carborane derivative Fc(2)SBCp(1) is highly effective in treating bacteremia caused by S. aureus and P. aeruginosa as well as interstitial pneumonia caused by S. aureus. This raises the possibility for the potential utilization of the new ferrocene-substituted carborane derivatives as promising antibacterial therapeutic agents against MDR bacterial infections in future clinical applications.