Guar gum-enhanced emission of gold nanoclusters for α-glucosidase activity detection and anti-diabetic agents screening in plant extracts.

The development of efficient fluorescent methods for α-glucosidase (α-Glu) detection and α-Glu inhibitor screening plays a critical role in the therapy of type 2 diabetes (T2D). Herein, guar gum (GG), a high-abundant and non-toxic natural polymer originated from the seeds of a drought-tolerant plant, Cyamposis tetragonolobus, was found to be able to enhance the fluorescence emission of gold nanoclusters (AuNCs) probe. The emission enhancement effect was achieved by using GG at very low concentrations (<1.0 wt%) and presented in a viscosity-dependent manner through increasing solvent reorientation time and inhibiting intramolecular motions of AuNCs. Furthermore, the enhanced emission of the AuNCs was quenched by Fe3+via dynamic quenching and then restored by α-Glu. Accordingly, a fluorimetric method was proposed for the determination of α-Glu. Owing to the fluorescence enhancement effect of GG on the AuNCs probe, the detection limit of the approach was 0.13 U L-1 and the detection range was up to 5 orders of magnitude from 0.2 to 4000 U L-1, which was much better than most current α-Glu detection methods. The approach was further applied to α-Glu inhibitors screening from natural plant extracts, providing great prospects for the prevention and treatment of T2D.

Plasmonically Modulated Gold Nanostructures for Photothermal Ablation of Bacteria.

With the wide utilization of antibiotics, antibiotic-resistant bacteria have been often developed more frequently to cause potential global catastrophic consequences. Emerging photothermal ablation has been attracting extensive research interest for quick/effective eradication of pathogenic bacteria from contaminated surroundings and infected body. In this field, anisotropic gold nanostructures with tunable size/morphologies have been demonstrated to exhibit their outstanding photothermal performance through strong plasmonic absorption of near-infrared (NIR) light, efficient light to heat conversion, and easy surface modification for targeting bacteria. To this end, this review first introduces thermal treatment of infectious diseases followed by photothermal therapy via heat generation on NIR-absorbing gold nanostructures. Then, the usual synthesis and spectral features of diversified gold nanostructures and composites are systematically overviewed with the emphasis on the importance of size, shape, and composition to achieve strong plasmonic absorption in NIR region. Further, the innovated photothermal applications of gold nanostructures are comprehensively demonstrated to combat against bacterial infections, and some constructive suggestions are also discussed to improve photothermal technologies for practical applications.

Animal heat activated cancer therapy by a traditional catalyst TiO2-Pd/graphene composites.

Cancer therapy is one of the most important challenges in clinical medicine. So far different methods have been developed for cancer therapy, such as radiation therapy, surgery, chemotherapy and photodynamic therapy. Here we propose a new concept for cancer therapy, i.e., killing the cancer cells simply via reactive oxygen species (ROS) generated by TiO2-Pd/graphene composites. Activated by animal heat of 37 °C, the electrons in the valence band can be excited to the conduction band of TiO2 via the energy levels of Pd species and graphene, generating ROS without light irradiation or electric excitation. The tumors in BALB/c mice are successfully regressed at animal heat without any other external conditions, such as radiation, UV, visible and IR irradiation. Our results suggest that the design of animal heat activated cancer therapy is a feasible concept for practical applications of cancer treatments.

Expression of Matrix Metalloproteinase-2, Tissue Inhibitor of Matrix Metalloproteinase-2 and CD147 in the Traditional Chinese Medicine "Compound T11" for Treatment of Chronic Liver Injury.

OBJECTIVES: To measure the expression of matrix metalloproteinase (MMP)-2, tissue inhibitor of matrix metalloproteinase inhibitor (TIMP)-2, and CD147 in mice with chronic liver injury induced by carbon tetrachloride after treatment with the traditional Chinese medicine (TCM) "Compound T11". METHOD: Sixty male ICR mice were divided randomly into 6 groups of 10: control (C), model (M), low-dose treatment (LT; 50 mg/mL of Compound T11), medium-dose treatment (MT, 100 mg/mL), high-dose treatment (HT, 150 mg/mL), and positive drug treatment (YT, 67.5 mg/mL). Each group was modeled for 7 weeks. Groups M, LT, MT, HT, and YT were injected (s.c.) with 20% carbon tetrachloride diluted with olive oil, and group C was given olive oil in the same way twice a week. After modeling, the treatment groups were administered Compound T11 at the concentrations shown above by oral gavage daily for 2 weeks, while group C was given 0.5% carboxymethyl cellulose sodium. After the final treatment, mice were killed and their liver tissues were excised. Immunohistochemical staining was performed to measure the protein expression of MMP-2, TIMP-2, and CD147, and western blotting was used to measure the protein expression of MMP-2, TIMP-2, CD147, and α-smooth muscle actin (SMA). MMP-2, TIMP-2, and CD147 mRNA expression was determined by quantitative fluorescence real-time PCR. RESULTS: Compound T11 increased the protein expression of MMP-2 and CD147 and decreased the protein expression of TIMP-2 and α-SMA. CONCLUSIONS: Treatment of chronic liver injury by TCM Compound T11 may be associated with changes to the expression of MMP-2 and CD147, and the inhibition of TIMP-2 expression.

Net-like assembly of Au nanoparticles as a highly active substrate for surface-enhanced Raman and infrared spectroscopy.

Anodic aluminum oxide (AAO) templates were employed to filtrate and assemble Au nanoparticles by the pressure difference method. It was found that the colloidal Au nanoparticles can be uniformly arranged as nanonet assembly on the AAO surface. The net-assembled Au nanoparticles are clean and closely packed with nanochains. Taking fullerene C60/C70 as probe molecules, high-quality surface-enhanced Raman scattering (SERS) spectra were observed. The net-assembled Au nanoparticles even synchronously support the observation of surface-enhanced infrared absorption (SEIRA) spectra of the fullerene C60/C70. These results indicate that the AAO template filtrated with net-assembled Au nanoparticles is a highly active substrate for surface-enhanced spectroscopy.