Magnetic Nanozyme Based on Loading Nitrogen-Doped Carbon Dots on Mesoporous Fe3O4 Nanoparticles for the Colorimetric Detection of Glucose.

The simple and accurate monitoring of blood glucose level is of great significance for the prevention and control of diabetes. In this work, a magnetic nanozyme was fabricated based on loading nitrogen-doped carbon dots (N-CDs) on mesoporous Fe3O4 nanoparticles for the colorimetric detection of glucose in human serum. Mesoporous Fe3O4 nanoparticles were easily synthesized using a solvothermal method, and N-CDs were then prepared in situ and loaded on the Fe3O4 nanoparticles, leading to a magnetic N-CDs/Fe3O4 nanocomposite. The N-CDs/Fe3O4 nanocomposite exhibited good peroxidase-like activity and could catalyze the oxidation of the colorless enzyme substrate 3,3',5,5'-tetramethylbenzidine (TMB) to blue TMB oxide (ox-TMB) in the presence of hydrogen peroxide (H2O2). When the N-CDs/Fe3O4 nanozyme was combined with glucose oxidase (Gox), Gox catalyzed the oxidization of glucose, producing H2O2 and leading to the oxidation of TMB under the catalysis of the N-CDs/Fe3O4 nanozyme. Based on this mechanism, a colorimetric sensor was constructed for the sensitive detection of glucose. The linear range for glucose detection was from 1 to 180 µM, and the limit of detection (LOD) was 0.56 µM. The recovered nanozyme through magnetic separation showed good reusability. The visual detection of glucose was also realized by preparing an integrated agarose hydrogel containing the N-CDs/Fe3O4 nanozyme, glucose oxidase, and TMB. The colorimetric detection platform has an enormous potential for the convenient detection of metabolites.

Casp3/7-Instructed Intracellular Aggregation of Fe3O4 Nanoparticles Enhances T2 MR Imaging of Tumor Apoptosis.

Large magnetic nanoparticles or aggregates are advantageous in their magnetic resonance properties over ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles (NPs), but the former are cleared faster from the blood pool. Therefore, the "smart" strategy of intracellular aggregation of USPIO NPs is required for enhanced T2-weighted MR imaging. Herein, employing an enzyme-instructed condensation reaction, we rationally designed a small molecule Ac-Asp-Glu-Val-Asp-Cys(StBu)-Lys-CBT (1) to covalently modify USPIO NPs to prepare monodispersive Fe3O4@1 NPs. In vitro results showed that Fe3O4@1 NPs could be subjected to caspase 3 (Casp3)-instructed aggregation. T2 phantom MR imaging showed that the transverse molar relaxivity (r2) of Fe3O4@1 NPs with Casp3 or apoptotic HepG2 cells was significantly larger than those of control groups. In vivo tumor MR imaging results indicated that Fe3O4@1 NPs could be specifically applied for enhanced T2 MR imaging of tumor apoptosis. We propose that the enzyme-instructed intracellular aggregation of Fe3O4 NPs could be a novel strategy for the design of "smart" probes for efficient T2 MR imaging of in vivo biomarkers.

Clinical Value of Contrast-Enhanced Ultrasound in Diagnosis of Hyperechoic Liver Lesions.

BACKGROUND: The purpose of this study was to investigate the values of contrast-enhanced ultrasound (CEUS) in the diagnosis and differential diagnosis of hyperechoic liver lesions. MATERIAL AND METHODS: The CEUS findings of 102 patients with hyperechoic liver lesions identified by 2-dimensional ultrasound in the Affiliated Tumor Hospital of Guangxi Medical University were reviewed and analyzed. RESULTS: A total of 135 lesions were analyzed, of which malignant lesions were found in 72 patients and benign lesions in 63, with a CEUS accuracy rate of 91.11%, which was significantly higher than that of conventional ultrasound (74.81%; P<0.05). CONCLUSIONS: CEUS can improve the accuracy rate of ultrasonography in the diagnosis and differential diagnosis of hyperechoic liver lesions.

Intracellular Self-Assembly of Taxol Nanoparticles for Overcoming Multidrug Resistance.

Multidrug resistance (MDR) remains the biggest challenge in treating cancers. Herein we propose the intracellular self-assembly of nanodrugs as a new strategy for overcoming MDR. By employing a biocompatible condensation reaction, we rationally designed a taxol derivative Ac-Arg-Val-Arg-Arg-Cys(StBu)-Lys(taxol)-2-cyanobenzothiazole (CBT-Taxol) which could be subjected to furin-controlled condensation and self-assembly of taxol nanoparticles (Taxol-NPs). In vitro and in vivo studies indicated that, compared with taxol, CBT-Taxol showed a 4.5-fold or 1.5-fold increase in anti-MDR effects, respectively, on taxol-resistant HCT 116 cancer cells or tumors without being toxic to the cells or the mice. Our results demonstrate that structuring protease-susceptible agents and assembling them intracellularly into nanodrugs could be a new optimal strategy for overcoming MDR.

The Value of CEUS LI-RADS combined with AFP in early diagnosis of hepatocellular carcinoma in low- and high-risk patients.

BACKGROUND: We found that the occurrence of hepatocellular carcinoma (HCC) has increased significantly in non-cirrhotic individuals, with HCC being frequently overlooked or misdiagnosed. Contrast-enhanced ultrasound (CEUS) Liver Imaging Reporting and Data System (LI-RADS) is known to have a high diagnostic quality in high-risk HCC patients. Therefore, we aimed to compare the detection accuracy of CEUS LI-RADS for HCC between low- and high-risk individuals, to confirm its value in low-risk patients at increased risk of HCC, but not yet included in the high-risk groups of LI-RADS. In addition, since CEUS LR-4 and LR-M categories contain a relatively high proportion of HCC, and serum alpha-fetoprotein (AFP) is the most commonly used biomarker for HCC, and the clinically valid, we attempted to further improve the early diagnostic capability of CEUS LI-RADS for HCC in the low-risk and high-risk patients by combining CEUS LR-4 and LR-M categories with AFP. METHODS: We defined high-risk groups (HR)-included in the high-risk patients of LI-RADS, low-risk groups (LR)-not included in the high-risk patients of LI-RADS and enrolled 189 HCC patients with LR and HR settings in a retrospective study. All lesions were confirmed histopathologically. The CEUS LI-RADS accuracy for detecting HCC in these two patients was compared. In addition, the diagnostic algorithm in our study was proposed (for CEUS LR-4 and LR-M patients with AFP>20 ng/ml). we analyzed the ability of CEUS LI-RADS as a valid method of establishing the early diagnosis of HCC in LR and HR patients by combining LR-4 and LR-M categories with AFP. RESULTS: Through comparative analysis, the specificity of the CEUS LR-5 category for HCC in the HR group was 78.4%, whereas in the LR group, it was 94.2%. Meanwhile, the sensitivity (63.2% vs. 63.0%) and positive predictive value (PPV) (75.0% vs. 88.7%) did not differ between the LR and HR groups ( P = 0.990, P = 0.299). It is noteworthy that there were the high proportion of HCC in CEUS LR-4 and LR-M categories in our cases and when we combined CEUS LR-4 and LR-M categories with AFP significantly improved the sensitivity by 21.0% (84.2%) in the LR group, and by 16.0% (79.0%) in the HR group, with statistically difference in sensitivity after combination in the HR group ( P = 0.014). CONCLUSIONS: The CEUS LR-5 category has real meaningful utility in the diagnosis of HCC in both LR and HR patients. The early detection power of the CEUS LI-RADS category for HCC patients was further increased when the CEUS LR-4 and LR-M categories were combined with elevated AFP.

Vertically-Ordered Mesoporous Silica Films for Electrochemical Detection of Hg(II) Ion in Pharmaceuticals and Soil Samples.

Rapid and simple determination of mercury ion (Hg2+) in pharmaceuticals and soil samples is vital for human health and the environmental monitoring. Vertically-ordered mesoporous silica films (VMSF) supported by the indium tin oxide (ITO) electrode surface were prepared by electrochemically assisted self-assembly method and utilized for electrochemical detection of Hg2+. Owing to the negatively charged channel walls and ultrasmall pore diameter, VMSF displays obvious cationic selectivity and has highly electrostatic interaction for Hg2+, giving rise to the strong electrochemical signals. By recording the anodic stripping signals of adsorbed Hg2+ using differential pulse voltammetry, quantitative detection of Hg2+ was achieved with a wide linear range (0.2 µM-20 µM) and a low limit of detection (3 nM). Furthermore, considering the anti-fouling and anti-interference capacity of VMSF, the proposed VMSF/ITO sensor has been successfully applied to detect Hg2+ in pharmaceuticals and soil samples without tedious pretreatment processes of samples.

Photo-degradable micelles for co-delivery of nitric oxide and doxorubicin.

The emerging therapeutic potential of nitric oxide (NO) has spurred the rapid development of NO donors to maximize the therapeutic outcomes. Although polymeric NO donors have shown extended release times and optimized biodistributions, many of these macromolecular NO donors are non-degradable. Herein, we devise a macromolecular NO donor by integrating photoresponsive N,N'-dinitroso-p-phenylenediamine (DNP) derivatives into the middle block of an amphiphilic triblock copolymer and the photo-mediated NO release process transforms the DNP to quinondimine (QDI) moieties, enabling the degradation of the resulting polymers due to the spontaneous hydrolysis of QDI moieties. We demonstrated that the NO release process could be selectively activated under visible light irradiation both in vitro and in vivo. Moreover, the simultaneous release of NO and DOX could be achieved under visible light by taking advantage of the NO release-mediated micelle disassembly. This work provides new insights into the design of degradable macromolecular NO donors where the polymer breakdown could be actuated by triggered NO release.

MicroRNA-587 Functions as a Tumor Suppressor in Hepatocellular Carcinoma by Targeting Ribosomal Protein SA.

BACKGROUND: Hepatocellular carcinoma (HCC) is one of the most highly aggressive cancer worldwide with an extremely poor prognosis. Evidence has revealed that microRNA-587 (miR-587) is abnormally expressed in a series of cancers. However, its expressions and functions in HCC have not been clearly acknowledged. METHODS: We detected the expression level of miR-587 both in the Gene Expression Omnibus (GEO) database and 86 paired clinical HCC tissues together with paired adjacent normal tissues by quantitative real-time PCR (qRT-PCR). Afterwards, the transfected HCC cell line SMMC-7721 cells were collected for the cell proliferation assay, cell-cycle arrest, cell migration, and invasion assays to explore the roles of miR-587 in regulating cellular function. In addition, bioinformatics analysis, combined with qRT-PCR and dual-luciferase reporter assays, were performed to confirm whether ribosomal protein SA (RPSA) mRNA was the direct target gene of miR-587. Moreover, the Cancer Genome Atlas (TCGA) and GEO databases as well as 86 paired clinical HCC tissues were used to verify the negative regulation between miR-587 and RPSA. RESULTS: In the present study, both the GEO database (GSE36915 and GSE74618) analysis and qRT-PCR analysis of 86 paired clinical tissues showed that miR-587 was significantly downregulated in HCC tissues. The overexpression of miR-587 inhibited proliferation, cell cycle, migration, and invasion in SMMC-7721 cells. In addition, miR-587 directly interacted with the 3'-untranslated region (UTR) of RPSA. Moreover, miR-587 overexpression directly suppressed RPSA expression, and the two genes were inversely expressed in HCC based on the analyses in TCGA and GEO (GSE36376) databases and qPCR analysis of 86 paired clinical tissues. CONCLUSION: Our results demonstrate that miR-587 is downexpressed in HCC and regulates the cellular function by targeting RPSA.

Contrast-enhanced ultrasound for needle biopsy of thoracic lesions.

Two-dimensional ultrasound (US) and color doppler flow imaging are associated with certain limitations in the preprocedural evaluation and design of the puncture path for biopsies of thoracic lesions, such as a poorly defined boundary between the tumor and the atelectatic lesions in central lung cancer with atelectasis. Contrast-enhanced ultrasound (CEUS) can be valuable in the preoperative evaluation of the biopsy site and in increasing the accuracy of the biopsy. The present study investigated the value of clinical application of CEUS in US-guided core needle biopsy (US-CNB) in improving the diagnostic accuracy in thoracic lesions. A total of 120 patients with first-stage thoracic lesions from the Affiliated Tumor Hospital of Guangxi Medical University who underwent US-CNB were recruited and randomnly assigned to a conventional US group (n=66) and a CEUS group (n=54). All patients underwent preoperative evaluation and US-guided puncture of thoracic lesions. The intergroup differences in sonographic features, biopsy duration, biopsy success rate and complications were assessed. The CEUS group had a higher rate of detection of necrotic tissue (40.7% vs. 16.7%; χ2=8.633; P=0.003) and change of initial puncture path (48.1%) compared with the US group. In central lung cancer with atelectasis, the ability to distinguish between tumor and atelectasis was higher in the CEUS group compared with the conventional US group (31.5 vs. 7.6%; χ2=11.336; P=0.001). In addition, the CEUS group had a higher puncture success (96.3 vs. 80.3%; χ2=6.946; P=0.008) and a lower complication rate (3.7% vs. 18.2%; χ2=6.041; P=0.014) compared with the US group. CEUS can identify necrotic areas and occult tumors within atelectatic lung tissue and can be used for guiding puncture biopsy of thoracic lesions to improve the diagnostic accuracy with greater comparative clinical utility than conventional US. Pre-biopsy CEUS is especially useful for patients undergoing repeated US-CNB and those with hypovascular lesions, atelectasis or necrosis.

Alkaline phosphatase-triggered assembly of etoposide enhances its anticancer effect.

Etoposide is a cancer-targeting drug but an overdose of etoposide leads to immunosuppression in patients. Therefore, the development of a new strategy to enhance its anticancer effect, while in the meantime alleviating its adverse effects, is important but challenging. In this work, with the assistance of a hydrogelator precursor Nap-Phe-Phe-Tyr(H2PO3)-OH (1P), etoposide phosphate (EP) was subjected to alkaline phosphatase (ALP)-triggered assembly, which obviously enhanced its anticancer efficacy in vitro and in vivo. In vitro tests indicated that the assembly of EP with 1P resulted in a slow release of etoposide and long-term inhibitory effects on HeLa cells. In vivo experiments indicated that, compared with those of EP-treated mice, the tumor growth of EP + 1P-treated mice was further inhibited while their body weight loss was alleviated. We envision that our hydrogelator-assisted assembly strategy could be applied to enhance the therapeutic effects of more drugs, while in the meantime alleviating their adverse effects in the future.

Contrast-Enhanced Ultrasound to Monitor Early Recurrence of Primary Hepatocellular Carcinoma after Curative Treatment.

OBJECTIVE: To evaluate contrast-enhanced ultrasound (CEUS) for monitoring early intrahepatic recurrence of primary hepatocellular carcinoma (HCC) after curative treatment. METHODS: We prospectively analyzed 97 patients (124 nodules) with primary HCC who underwent hepatic resection or radiofrequency ablation and subsequently experienced intrahepatic recurrence. Patients were assessed with conventional ultrasound and CEUS. They were also assessed with contrast-enhanced computed tomography (CECT) and/or magnetic resonance imaging (MRI). The image characteristics of CEUS of recurrent hepatocellular carcinoma and high-grade dysplastic nodules (HGDNs) were analyzed. In addition, the ability of CEUS and CECT/MRI to assess internal artery vascularization in recurrent disease was compared. RESULTS: CEUS of recurrent hepatocellular carcinoma showed hyperenhancement in the arterial phase in 96 of 99 nodules, and it showed hypo- or isoenhancement for portal venous and delayed phases. The most common enhancement patterns were "fast-in and slow-out" and "fast-in and fast-out". Based on the arterial hyperenhancement of lesions and with clinical data such as patient history of HCC and increased level of serum alpha-fetoprotein, the diagnostic accuracy of CEUS for recurrent HCC was significantly higher than that based on the enhancement pattern of "fast-in and fast-out". CEUS of HGDNs showed local or global hyperenhancement during the arterial phase, isoenhancement during the portal venous phase, and isoenhancement or slight hypoenhancement during the delayed phase. The enhancement pattern was "fast-in and slow-out". In some cases, it was difficult to differentiate HGDNs from recurrent disease using CEUS. Vascularization in recurrent disease was significantly higher when assessed by CEUS than when assessed with CECT/MRI (P < 0.05). For detecting recurrent disease, CEUS showed sensitivity of 97.0%, specificity of 68.0%, positive predictive value of 92.3%, and negative predictive value of 85.0%. The corresponding parameters for CECT/MRI were 71.7%, 72.0%, 88.8%, and 39.1%. CONCLUSION: Intrahepatic recurrent HCC and HGDNs with diameter ≤ 3.0 cm have a characteristic appearance on CEUS. This imaging modality may be effective for monitoring early intrahepatic recurrence after curative treatment of primary HCC.

Intracellular Self-Assembly of Cyclic d-Luciferin Nanoparticles for Persistent Bioluminescence Imaging of Fatty Acid Amide Hydrolase.

Fatty acid amide hydrolase (FAAH) overexpression induces several disorder symptoms in nerve systems, and therefore long-term tracing of FAAH activity in vivo is of high importance but remains challenging. Current bioluminescence (BL) methods are limited in detecting FAAH activity within 5 h. Herein, by rational design of a latent BL probe (d-Cys-Lys-CBT)2 (1), we developed a "smart" method of intracellular reduction-controlled self-assembly and FAAH-directed disassembly of its cyclic d-luciferin-based nanoparticles (i.e., 1-NPs) for persistent BL imaging of FAAH activity in vitro, in cells, and in vivo. Using aminoluciferin methyl amide (AMA), Lys-amino-d-luciferin (Lys-Luc), and amino-d-luciferin (NH2-Luc) as control BL probes, we validated that the persistent BL of 1 from luciferase-expressing cells or tumors was controlled by the activity of intracellular FAAH. With the property of long-term tracing of FAAH activity in vivo of 1, we envision that our BL precursor 1 could probably be applied for in vivo screening of FAAH inhibitors and the diagnosis of their related diseases (or disorders) in the future.

Bridging cells of three colors with two bio-orthogonal click reactions.

Cell-cell interactions play a crucial role in the development and function of multicellular organisms. To study cell-cell interactions in vitro, it is a big challenge for researchers to artificially build up cell junctions to bridge different types of cells for this purpose. Herein, by employing two orthogonal click reactions, we rationally designed four click reagents Mal-CBT, Mal-Cys, Mal-Alkyne, and Mal-N3 and successfully applied them to bridge cells of three colors. Orthogonality between these two click reactions was validated in solution and characterized with HPLC and ESI-MS analyses. After modifications of fluorescent protein-expressing prokaryotic Escherichia coli (E. coli) cells (or eukaryotic HEK 293T cells) of three colors with the reagents Mal-Cys, Mal-CBT and Mal-Alkyne, or Mal-N3 , the cells were sequentially bridged. The HEK 293T cells showed a higher efficiency of cell bridging than the E. coli cells. Finally, using optical tweezers, we quantitatively measured the bridging probability between Mal-Cys-modified and Mal-CBT-modified HEK 293 cells, as well as the rupture force between two bridged cells. We found that the CBT-Cys click reaction markedly improved the efficiency of cell bridging and the rupture force between two bridged cells was measured to be 153.8 pN at a force-loading rate of 49 pN s-1. Our results demonstrate that it is possible to use two (or n) orthogonal click reactions to bridge three (or n + 1) types of cells. Taking the biological importance of cell junctions into consideration, we anticipate that our method of bridging three types of cells with two bio-orthogonal click reactions will be a useful tool for biologists to study cell-cell interactions with more convenience and efficiency.