Synthesis of Water-Soluble [Au25(SR)18]- Using a Stoichiometric Amount of NaBH4.

Determination of the stoichiometry of reactions is a pivotal step for any chemical reactions toward a desirable product, which has been successfully achieved in organic synthesis. Here, we present the first precise determination of the stoichiometry for the reactions toward gold nanoparticle formation in the sodium borohydride reduction method. Leveraging on the real-time mass spectrometry technique, we have determined a precise balanced reaction, 32/ x [Au(SR)] x + 8 e- = [Au25(SR)18]- + 7 [Au(SR)2]- (here SR denotes a thiolate ligand), toward a stoichiometric synthesis of water-soluble [Au25(SR)18]-, where 8 electrons (from reducing agents) are sufficient to react with every 32 Au atoms, leading to the formation of high-purity [Au25(SR)18]-. More interestingly, by real-time monitoring of the growth process of thiolate-protected Au nanoclusters, we have successfully identified an important yet missing byproduct, [Au(SR)2]-. This study not only provides a new method for Au nanocluster synthesis using only a stoichiometric amount of reducing agent in aqueous solutions (although the synthesis of organic-soluble Au nanoclusters might require a more delicate design of synthetic chemistry) but also promotes the mechanistic understandings of the Au nanocluster growth process.

Molecular-Scale Ligand Effects in Small Gold-Thiolate Nanoclusters.

Because of the small size and large surface area of thiolate-protected Au nanoclusters (NCs), the protecting ligands are expected to play a substantial role in modulating the structure and properties, particularly in the solution phase. However, little is known on how thiolate ligands explicitly modulate the structural properties of the NCs at atomic level, even though this information is critical for predicting the performance of Au NCs in application settings including as a catalyst interacting with small molecules and as a sensor interacting with biomolecular systems. Here, we report a combined experimental and theoretical study, using synchrotron X-ray spectroscopy and quantum mechanics/molecular mechanics simulations, that investigates how the protecting ligands impact the structure and properties of small Au18(SR)14 NCs. Two representative ligand types, smaller aliphatic cyclohexanethiolate and larger hydrophilic glutathione, are selected, and their structures are followed experimentally in both solid and solution phases. It was found that cyclohexanethiolate ligands are significantly perturbed by toluene solvent molecules, resulting in structural changes that cause disorder on the surface of Au18(SR)14 NCs. In particular, large surface cavities in the ligand shell are created by interactions between toluene and cyclohexanethiolate. The appearance of these small molecule-accessible sites on the  NC surface demonstrates the ability of Au NCs to act as a catalyst for organic phase reactions. In contrast, glutathione ligands encapsulate the Au NC core via intermolecular interactions, minimizing structural changes caused by interactions with water molecules. The much better protection from glutathione ligands imparts a rigidified surface and ligand structure, making the NCs desirable for biomedical applications due to the high stability and also offering a structural-based explanation for the enhanced photoluminescence often reported for glutathione-protected Au NCs.

Storage of gold nanoclusters in muscle leads to their biphasic in vivo clearance.

Ultrasmall gold nanoclusters (Au NCs) show great potential in biomedical applications. Long-term biodistribution, retention, toxicity, and pharmacokinetics profiles are pre-requisites in their potential clinical applications. Here, the biodistribution, clearance, and toxicity of one widely used Au NC species-glutathione-protected Au NCs or GSH-Au NCs-are systematically investigated over a relatively long period of 90 days in mice. Most of the Au NCs are cleared at 30 days post injection (p.i.) with a major accumulation in liver and kidney. However, it is surprising that an abnormal increase of the Au amount in the heart, liver, spleen, lung, and testis is observed at 60 and 90 days p.i., indicating that the injected Au NCs form a V-shaped time-dependent distribution profile in various organs. Further investigations reveal that Au NCs are steadily accumulating in the muscle in the first 30 days p.i., and the as-stored Au NCs gradually release into the blood in 30-90 days p.i., which induces a re-distribution and re-accumulation of Au NCs in all blood-rich organs. Further hematology and biochemistry studies show that the re-accumulation of Au NCs still causes some liver toxicity at 30 days p.i. The muscle storage and subsequent release may give rise to the potential accumulation and toxicity risk of functional nanomaterials over long periods of time.

Identification of a highly luminescent Au22(SG)18 nanocluster.

The luminescence property of thiolated gold nanoclusters (Au NCs) is thought to involve the Au(I)-thiolate motifs on the NC surface; however, this hypothesis remains largely unexplored because of the lack of precise molecular composition and structural information of highly luminescent Au NCs. Here we report a new red-emitting thiolated Au NC, which has a precise molecular formula of Au22(SR)18 and exhibits intense luminescence. Interestingly, this new Au22(SR)18 species shows distinctively different absorption and emission features from the previously reported Au22(SR)16, Au22(SR)17, and Au25(SR)18. In stark contrast, Au22(SR)18 luminesces intensely at ∼665 nm with a high quantum yield of ∼8%, while the other three Au NCs show very weak luminescence. Our results indicate that the luminescence of Au22(SR)18 originates from the long Au(I)-thiolate motifs on the NC surface via the aggregation-induced emission pathway. Structure prediction by density functional theory suggests that Au22(SR)18 has two RS-[Au-SR]3 and two RS-[Au-SR]4 motifs, interlocked and capping on a prolate Au8 core. This predicted structure is further verified experimentally by Au L3-edge X-ray absorption fine structure analysis.

Toward understanding the growth mechanism: tracing all stable intermediate species from reduction of Au(I)-thiolate complexes to evolution of Au25 nanoclusters.

Despite 20 years of progress in synthesizing thiolated gold nanoclusters (Au NCs), the knowledge of their growth mechanism still lags behind. Herein the detailed process from reduction of Au(I)-thiolate complex precursors to the eventual evolution of and focusing to the atomically precise Au25 NCs was revealed for the first time by monitoring the time evolution of Au(I) precursor and Au NC intermediate species with ESI-MS. A two-stage, bottom-up formation and growth process was proposed: a fast stage of reduction-growth mechanism, followed by a slow stage of intercluster conversion and focusing. Balanced reactions of formation for each identified NC were suggested, backed by theoretical calculations of the thermodynamic driving force. This work advances one step further toward understanding the mechanism of formation and growth of thiolated Au NCs.

Balancing the rate of cluster growth and etching for gram-scale synthesis of thiolate-protected Au(25) nanoclusters with atomic precision.

We report a NaOH-mediated NaBH4 reduction method for the synthesis of mono-, bi-, and tri-thiolate-protected Au25 nanoclusters (NCs) with precise control of both the Au core and thiolate ligand surface. The key strategy is to use NaOH to tune the formation kinetics of Au NCs, i.e., reduce the reduction ability of NaBH4 and accelerate the etching ability of free thiolate ligands, leading to a well-balanced reversible reaction for rapid formation of thermodynamically favorable Au25 NCs. This protocol is facile, rapid (≤3 h), versatile (applicable for various thiolate ligands), and highly scalable (>1 g Au NCs). In addition, bi- and tri-thiolate-protected Au25 NCs with adjustable ratios of hetero-thiolate ligands were easily obtained. Such ligand precision in molecular ratios, spatial distribution and uniformity resulted in richly diverse surface landscapes on the Au NCs consisting of multiple functional groups such as carboxyl, amine, and hydroxy. Analysis based on NMR spectroscopy revealed that the hetero-ligands on the NCs are well distributed with no ligand segregation. The unprecedented synthesis of multi-thiolate-protected Au25 NCs may further promote the practical applications of functional metal NCs.

A bimetallic sulfide FeCoS4@rGO hybrid as a high-performance anode for potassium-ion batteries.

We synthesized a low metal-to-sulfur atomic ratio (0.5) FeCoS4, exhibiting high reversible specific capacity. Reduced graphene oxide was covered on the surface to improve the cycling stability and rate performance further. Density functional theory calculations show that composite materials can effectively increase the adsorption energy and enhance the diffusion kinetics.

Glutathione-protected silver nanoclusters as cysteine-selective fluorometric and colorimetric probe.

The integration of the unique thiol-Ag chemistry and the specific steric hindrance from the organic layer of fluorescent Ag nanoclusters (AgNCs) was first developed in this work to achieve a simple detection of cysteine (Cys) with high selectivity and sensitivity. The key design is a strongly red-emitting AgNC protected by the interference biothiol, glutathione, or GSH (hereafter referred to as GSH-AgNCs), where both the physicochemical properties (Ag surface chemistry and fluorescence) of the NC core and the physical properties (e.g., steric hindrance) of the organic shell were fully utilized for Cys detection with three major features. First, owing to the specific thiol-Ag interaction, the fluorescent GSH-AgNCs showed superior selectivity for Cys over the other 19 natural amino acids (nonthiol-containing). Second, the GSH protecting layer on the NC surface made possible the differentiation of Cys from GSH (or other large-sized thiol molecules) simply by their size. Third, the ultrasmall size of GSH-AgNCs and the high affinity of the thiol-Ag interaction provided high sensitivity for Cys detection with a detection limit of <3 nM. The assay developed in this study is of interest not only because it provides a simple Cys sensor with high selectivity and sensitivity but also because it exemplifies the utilization of the physical properties of organic ligands on the nanomaterial surface to further improve the sensor performance, which could open a new design strategy for other sensor development.

Alisertib exerts KRAS allele­specific anticancer effects on colorectal cancer cell lines.

The aim of the present study was to examine the effects of alisertib (ALS) on RAS signaling pathways against a panel of colorectal cancer (CRC) cell lines and engineered Flp-In stable cell lines expressing different Kirsten rat sarcoma virus (KRAS) mutants. The viability of Caco-2KRAS wild-type, Colo-678KRAS G12D, SK-CO-1KRAS G12V, HCT116KRAS G13D, CCCL-18KRAS A146T and HT29BRAF V600E cells was examined by Cell Titer-Glo assay, and that of stable cell lines was monitored by IncuCyte. The expression levels of phosphorylated (p-)Akt and p-Erk as RAS signal outputs were measured by western blotting. The results suggested that ALS exhibited different inhibitory effects on cell viability and different regulatory effects on guanosine triphosphate (GTP)-bound RAS in CRC cell lines. ALS also exhibited various regulatory effects on the PI3K/Akt and mitogen-activated protein kinase (MAPK) pathways, the two dominant RAS signaling pathways, and induced apoptosis and autophagy in a RAS allele-specific manner. Combined treatment with ALS and selumetinib enhanced the regulatory effects of ALS on apoptosis and autophagy in CRC cell lines in a RAS allele-specific manner. Notably, combined treatment exhibited a synergistic inhibitory effect on cell proliferation in Flp-In stable cell lines. The results of the present study suggested that ALS differentially regulates RAS signaling pathways. The combined approach of ALS and a MEK inhibitor may represent a new therapeutic strategy for precision therapy for CRC in a KRAS allele-specific manner; however, this effect requires further study in vivo.

From aggregation-induced emission of Au(I)-thiolate complexes to ultrabright Au(0)@Au(I)-thiolate core-shell nanoclusters.

A fundamental understanding of the luminescence of Au-thiolate nanoclusters (NCs), such as the origin of emission and the size effect in luminescence, is pivotal to the development of efficient synthesis routes for highly luminescent Au NCs. This paper reports an interesting finding of Au(I)-thiolate complexes: strong luminescence emission by the mechanism of aggregation-induced emission (AIE). The AIE property of the complexes was then used to develop a simple one-pot synthesis of highly luminescent Au-thiolate NCs with a quantum yield of ~15%. Our key strategy was to induce the controlled aggregation of Au(I)-thiolate complexes on in situ generated Au(0) cores to form Au(0)@Au(I)-thiolate core-shell NCs where strong luminescence was generated by the AIE of Au(I)-thiolate complexes on the NC surface. We were able to extend the synthetic strategy to other thiolate ligands with added functionalities (in the form of custom-designed peptides). The discovery (e.g., identifying the source of emission and the size effect in luminescence) and the synthesis protocols in this study can contribute significantly to better understanding of these new luminescence probes and the development of new synthetic routes.

Construction and validation of a glycolysis-related lncRNA signature for prognosis prediction in Stomach Adenocarcinoma.

Background: Glycolysis is closely related to the occurrence and progression of gastric cancer (GC). Currently, there is no systematic study on using the glycolysis-related long non-coding RNA (lncRNA) as a model for predicting the survival time in patients with GC. Therefore, it was essential to develop a signature for predicting the survival based on glycolysis-related lncRNA in patients with GC. Materials and methods: LncRNA expression profiles, containing 375 stomach adenocarcinoma (STAD) samples, were obtained from The Cancer Genome Atlas (TCGA) database. The co-expression network of lncRNA and glycolysis-related genes was used to identify the glycolysis-related lncRNAs. The Kaplan-Meier survival analysis and univariate Cox regression analysis were used to detect the glycolysis-related lncRNA with prognostic significance. Then, Bayesian Lasso-logistic and multivariate Cox regression analyses were performed to screen the glycolysis-related lncRNA with independent prognostic significance and to develop the risk model. Patients were assigned into the low- and high-risk cohorts according to their risk scores. A nomogram model was constructed based on clinical information and risk scores. Gene Set Enrichment Analysis (GSEA) was performed to visualize the functional and pathway enrichment analyses of the glycolysis-related lncRNA. Finally, the robustness of the results obtained was verified in an internal validation data set. Results: Seven glycolysis-related lncRNAs (AL353804.1, AC010719.1, TNFRSF10A-AS1, AC005586.1, AL355574.1, AC009948.1, and AL161785.1) were obtained to construct a risk model for prognosis prediction in the STAD patients using Lasso regression and multivariate Cox regression analyses. The risk score was identified as an independent prognostic factor for the patients with STAD [HR = 1.315, 95% CI (1.056-1.130), p < 0.001] via multivariate Cox regression analysis. Receiver operating characteristic (ROC) curves were drawn and the area under curve (AUC) values of 1-, 3-, and 5-year overall survival (OS) were calculated to be 0.691, 0.717, and 0.723 respectively. Similar results were obtained in the validation data set. In addition, seven glycolysis-related lncRNAs were significantly enriched in the classical tumor processes and pathways including cell adhesion, positive regulation of vascular endothelial growth factor, leukocyte transendothelial migration, and JAK_STAT signaling pathway. Conclusion: The prognostic prediction model constructed using seven glycolysis-related lncRNA could be used to predict the prognosis in patients with STAD, which might help clinicians in the clinical treatment for STAD.

Protective effect of curcumin against irinotecan­induced intestinal mucosal injury via attenuation of NF­κB activation, oxidative stress and endoplasmic reticulum stress.

Irinotecan (CPT­11) is a DNA topoisomerase I inhibitor which is widely used in clinical chemotherapy, particularly for colorectal cancer treatment. However, late­onset diarrhea is one of the severe side­effects of this drug and this restricts its clinical application. The present study aimed to investigate the protective effects of curcumin treatment on CPT­11­induced intestinal mucosal injury both in vitro and in vivo and to elucidate the related mechanisms involved in these effects. For this purpose, mice were intraperitoneally injected with CPT­11 (75 mg/kg) for 4 days to establish a model of late­onset diarrhea. Curcumin (100 mg/kg) was intragastrically administered 8 days before the injection of CPT­11. Injury to small intestinal tissues was examined by H&E staining. The protein expression of prolyl 4­hydroxylase subunit beta (P4HB) and peroxiredoxin 4 (PRDX4) was detected by immunohistochemistry, as well as western blot analysis. IEC­6 cell viability was detected by MTT assay. Flow cytometry was performed to examine the cell apoptotic rate, mitochondrial membrane potential and reactive oxygen species (ROS) generation. Immunofluorescence was used to observe the localization of nuclear factor (NF)­κB. The levels of cleaved caspase­3, glucose­regulated protein, 78 kDa (GRP78), P4HB, PRDX4 and CHOP were detected by western blot analysis. The results revealed that in vivo, curcumin effectively attenuated the symptoms of diarrhea and abnormal intestinal mucosa structure induced by CPT­11 in nude mice. Treatment with curcumin also increased the expression of P4HB and PRDX4 in the tissue of the small intestine. In vitro, curcumin, exhibited little cytotoxicity when used at concentrations <2.5 µg/ml for 24 h in IEC­6 cells. At this concentration, curcumin also improved cell morphology, inhibited apoptosis, maintained mitochondrial membrane potential and reduced the elevated levels of ROS induced by CPT­11 (20 µg/ml). Furthermore, curcumin abolished NF­κB signal transduction and protected the cells from CPT­11­induced apoptosis by upregulating the expression of molecular chaperones, such as GRP78, P4HB and PRDX4, and suppressing the levels of the apoptosis­related proteins, CHOP and cleaved caspase­3. On the whole, our data indicate that curcumin exerted protective effects against CPT­11­induced intestinal mucosa injury. The protective effects of curcumin are mediated by inhibiting the activation of NF­κB, and suppressing oxidative stress and endoplasmic reticulum stress.

Laparoscopic versus Open Surgery in Lateral Lymph Node Dissection for Advanced Rectal Cancer: A Meta-Analysis.

AIM: To compare the clinical efficacies between laparoscopic and conventional open surgery in lateral lymph node dissection (LLND) for advanced rectal cancer. METHODS: We comprehensively searched PubMed, Embase, Cochrane Library, CNKI, and Wanfang Data and performed a cumulative meta-analysis. According to inclusion criteria and exclusion criteria, all eligible randomized controlled trials (RCTs) or retrospective or prospective comparative studies assessing the two techniques were included, and then a meta-analysis was performed by using RevMan 5.3 software to assess the difference in clinical and oncological outcomes between the two treatment approaches. RESULTS: Eight studies involving a total of 892 patients were finally selected, with 394 cases in the laparoscopic surgery group and 498 cases in the traditional open surgery group. Compared with the traditional open group, the laparoscopic group had a longer operative time (WMD = 81.56, 95% CI (2.09, 142.03), P = 0.008), but less intraoperative blood loss (WMD = -452.18, 95% CI (-652.23, -252.13), P < 0.00001), shorter postoperative hospital stay (WMD = -5.30, 95% CI (-8.42, -2.18), P = 0.0009), and higher R0 resection rate (OR = 2.17, 95% CI (1.14, 4.15), P = 0.02). There was no significant difference in the incidence of surgical complications between the two groups (OR = 0.52, 95% CI (0.26, 1.07), P = 0.08). Lateral lymph node harvest, lateral lymph node metastasis, local recurrence, 3-year overall survival, and 3-year disease-free survival did not differ significantly between the two approaches (P > 0.05). CONCLUSION: Laparoscopic LLND has a similar efficacy in oncological outcomes and postoperative complications to the conventional open surgery, with the advantages of reduced intraoperative blood loss, shorter postoperative hospital stay, and higher R0 resection rate, and tumor radical cure is similar to traditional open surgery. Laparoscopic LLND is a safe and feasible surgical approach, and it may be used as a standard procedure in LLND for advanced rectal cancer.

Comparison of outcomes of complete mesocolic excision with conventional radical resection performed by laparoscopic approach for right colon cancer.

BACKGROUND: This retrospective study compared the outcomes of laparoscopic complete mesocolic excision (CME) guided by superior mesenteric artery with laparoscopic conventional radical resection (CRR) performed for right-sided colon cancer. METHODS: Patients with right-sided colon cancer underwent CME (n=107; January 2011 to December 2015) or CRR (n=60; January 2008 to December 2010). RESULTS: The 2 groups were comparable regarding age, gender, body mass index, maximum tumor diameter, and tumor stage. In the CME group, the distances between the tumor and the high vascular tie (HVT; 12.6 cm), and between the closest bowel wall and HVT (10.4±0.9 cm) was significantly greater than that of the CRR group (11.5 cm and 9.3±1.0 cm, respectively; P<0.001). In the CME group, the number of retrieved lymph nodes (23.2) was significantly higher, and the volume of intraoperative bleeding (108.4 mL) was less than that of the CRR (14.0 and 128.7 mL; P<0.001). The length of resected bowel in the 2 groups was similar (25.8±0.7 cm and 25.5±2.1 cm; P=0.106), as was the operative time, postoperative hospitalization, time of first bowel movement, and complications. The 3-year recurrence rate of the CME group (8.4%) was significantly lower than that of the CRR (20.0%), the 3-year overall survival was significantly higher (93.5% cf. 85.0%), and the survival rates of T4 stage, N1 stage, pTNM stage II, pTNM stage III and lympho vascular invasion were significantly higher (P<0.05). The 2 groups were similar for survival rates of Tis, T1, T2, T3, N2 stage, pTNM stage I and perineural invasion (P>0.05). CONCLUSION: CME for right-sided colon cancer guided by superior mesenteric artery has similar short-term outcomes, higher lymph node yield, and higher 3-year overall survival compared with CRR.

Atomic-Precision Gold Clusters for NIR-II Imaging.

Near-infrared II (NIR-II) imaging at 1100-1700 nm shows great promise for medical diagnosis related to blood vessels because it possesses deep penetration and high resolution in biological tissue. Unfortunately, currently available NIR-II fluorophores exhibit slow excretion and low brightness, which prevents their potential medical applications. An atomic-precision gold (Au) cluster with 25 gold atoms and 18 peptide ligands is presented. The Au25 clusters show emission at 1100-1350 nm and the fluorescence quantum yield is significantly increased by metal-atom doping. Bright gold clusters can penetrate deep tissue and can be applied in in vivo brain vessel imaging and tumor metastasis. Time-resolved brain blood-flow imaging shows significant differences between healthy and injured mice with different brain diseases in vivo. High-resolution imaging of cancer metastasis allows for the identification of the primary tumor, blood vessel, and lymphatic metastasis. In addition, gold clusters with NIR-II fluorescence are used to monitor high-resolution imaging of kidney at a depth of 0.61 cm, and the quantitative measurement shows 86% of the gold clusters are cleared from body without any acute or long-term toxicity at a dose of 100 mg kg-1 .

Curcumin enhances the effects of irinotecan on colorectal cancer cells through the generation of reactive oxygen species and activation of the endoplasmic reticulum stress pathway.

Although initially effective against metastatic colorectal cancer (CRC), irinotecan-based chemotherapy leads to resistance and adverse toxicity. Curcumin is well known for its anti-cancer effects in many cancers, including CRC. Here, we describe reactive oxygen species (ROS) generation and endoplasmic reticulum (ER) stress as important mechanisms by which curcumin enhances irinotecan's effects on CRC cells. CRC cell lines were treated with curcumin and/or irinotecan for 24 h, and then evaluated using cell proliferation assays, cell apoptosis assays, cell cycle analysis, intracellular Ca2+ measurements, ROS measurements and immunoblotting for key ER stress-related proteins. We found that cell viability was inhibited and apoptosis was increased, accompanied by ROS generation and ER stress activation in CRC cells treated with curcumin alone or in combination with irinotecan. Blocking ROS production attenuated the expression of two markers of ER stress: binding of immunoglobulin protein (BIP) and CCAAT/enhancer-binding protein homologous protein (CHOP). Blocking CHOP expression using RNA interference also inhibited ROS generation. These results demonstrated that curcumin could enhance the effects of irinotecan on CRC cells by inhibiting cell viability and inducing cell cycle arrest and apoptosis, and that these effects may be mediated, in part, by ROS generation and activation of the ER stress pathway.

Synthesis of thiolate-protected Au nanoparticles revisited: U-shape trend between the size of nanoparticles and thiol-to-Au ratio.

We report a new understanding of the factors controlling the size of thiolate-protected gold nanoparticles (Au NPs): the formation and the state of a protecting layer (Au(i)-thiolate motifs) outside the gold core determine the size of Au NPs, depending on the feeding thiol-to-Au ratio. As a result, a U-shape trend is identified between the size of Au NPs and the thiol-to-Au ratio as opposed to the commonly expected decreasing trend.

Luminescent Metal Nanoclusters with Aggregation-Induced Emission.

Thiolate-protected metal nanoclusters (or thiolated metal NCs) have recently emerged as a promising class of functional materials because of their well-defined molecular structures and intriguing molecular-like properties. Recent developments in the NC field have aimed at exploring metal NCs as novel luminescent materials in the biomedical field because of their inherent biocompatibility and good photoluminescence (PL) properties. From the fundamental perspective, recent advances in the field have also aimed at addressing the fundamental aspects of PL properties of metal NCs, shedding some light on developing efficient strategies to prepare highly luminescent metal NCs. In this Perspective, we discuss the physical chemistry of a recently discovered aggregation-induced emission (AIE) phenomenon and show the significance of AIE in understanding the PL properties of thiolated metal NCs. We then explore the unique physicochemical properties of thiolated metal NCs with AIE characteristics and highlight some recent developments in synthesizing the AIE-type luminescent metal NCs. We finally discuss perspectives and directions for future development of the AIE-type luminescent metal NCs.

Boiling water synthesis of ultrastable thiolated silver nanoclusters with aggregation-induced emission.

A facile boiling water synthesis protocol has been developed to synthesize thiolated Ag nanoclusters with a core-shell Ag(0)@Ag(i)-thiolate structure, which was formed through condensation of Ag(i)-thiolate complexes on the surface of an in situ formed Ag(0) core. The as-synthesized thiolated Ag nanoclusters feature strong luminescence via aggregation-induced-emission (AIE).

Theranostic vitamin E TPGS micelles of transferrin conjugation for targeted co-delivery of docetaxel and ultra bright gold nanoclusters.

The aim of this work was to develop an advanced theranostic micelles of D-alpha-tocopheryl polyethylene glycol 1000 succinate (TPGS), which are conjugated with transferrin for targeted co-delivery of docetaxel (DTX) as a model drug and ultra bright gold clusters (AuNC) as a model imaging agent for simultaneous cancer imaging and therapy. The theranostic micelles with and without transferrin conjugation were prepared by the solvent casting method and characterized for their particle size, polydispersity, surface chemistry, drug encapsulation efficiency, drug loading and cellular uptake efficiency. Transferrin receptors expressing MDA-MB-231-luc breast cancer cells and NIH-3T3 fibroblast cells (control cells without transferrin receptor expression) were employed as an in vitro model to access cytotoxicity of the formulations. The overexpression of transferrin receptor on the surface of MDA-MB-231-luc cells was confirmed by flow cytometry. The biodistribution study and theranostic efficacy of the micelles were investigated by using the Xenogen IVIS(®) Spectrum imaging system, which includes AuNC based fluorescence imaging and luciferase induced bioluminescence imaging on MDA-MB-231-luc tumor bearing SCID mice. The IC50 values demonstrated that the non-targeted and targeted micelles could be 15.31 and 71.73 folds more effective than Taxotere(®) after 24 h treatment with the MDA-MB-231-luc cells. Transferrin receptor targeted delivery of such micelles was imaged in xenograft model and showed their great advantages for real-time tumor imaging and inhibition of tumor growth.