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In order to investigate how to enhance the teeth fracture resistance after the post and core treatment, an in vitro study was conducted to measure the fracture resistance of endodontically treated teeth restored with cast post and core with two kinds of surface treatment technology and acid etching preparation on the dentinal surface. Sixty-four recently extracted human single-rooted first premolars were endodontically treated and sectioned approximately 1.5 mm above the cementoenamel junction to remove the coronal portion. Each specimen received a cast post, core build-up and a metal alloy crown restoration. All teeth were randomly divided into the smooth surface post, core repair group, the sand blasting surface post, and core repair group, each group was divided into 10 s, 30 s, 60 s acid corrosion treatment group and control group. In acid test groups, an acid etching solution was applied for 10, 30 and 60 seconds, respectively, to the root canal wall surface. Each specimen was embedded in acrylic resin block and tested in an electronic universal testing machine. Fracture loads results showed that canal acid etching could increase teeth fracture resistance strength both in smooth groups and sandblasting group, and achieved the best effect when acid etching for 30 s. Sand spray treatment on the surface of the cast metal post can improve the flexural strength of the teeth after postcrown restoration. Acid etching on the root canal wall surfaces and sand spray treatment on the surface of the cast metal post can improve the flexural strength of the root after post-crown restoration. Therefore, these two methods could be used to strengthen the tooth fracture resistance, and maintain the long-term therapeutic effect of cast post and core restoration.

Constructing self-supported nanostructures on conductive substrates is an effective strategy to achieve non-enzymatic glucose sensors that possessing good reusability, reproducibility and stability. In the present study, vertical aligned CuO nanosheets on Cu foam are prepared with an in-situ electrochemical process including Cu-based metal-organic framework growing and subsequent electrochemical conversion. The scanning electron microscope results reveal that the totally electrochemical preparation guarantees the CuO nanosheets homogeneously free-standing on the Cu foam. The vertical aligned architecture endows the CuO/Cu electrodes good performances when using them as non-enzymatic glucose sensors, including a detection limit of 330 nM and a sensitivity of 33.95 mA cm−2 mM−1. We suggest that the facilitated ion transport in the vertical aligned architecture and the good conductivity originated from the totally electrochemical synthesis are responsible for the marked performances. More importantly, the good controllability of electrochemical preparation leads to remarkable reusability, reproducibility and stability of the electrodes, verified by multi-test of one electrode, consistency of multi-electrode and periodic test of one electrode in a long term. The practical detection of CuO/Cu electrodes on serum samples indicates the results are basically consistent with the clinical reports from hospital, further indicating their attractive potential in practical application.

Non-enzymatic glucose sensors are attracting significant attention owing to their low cost, storage convenience and reusability; however, their poor anti-interference caused by their weak selectivity towards glucose limits their practicability. In the present study, a MIL-53(NiFe) metal-organic framework (MOF) was prepared on Ni foam to serve as a self-supported electrode for non-enzymatic glucose detection. Due to the abundant active sites in the MIL-53(NiFe) MOF and its good stability in an alkaline solution, the sensors exhibited a high sensitivity (41.95 mA mM-1 cm-2) and a low detection limit (0.67 μM). Moreover, the molecular sieve effect of the MIL-53(NiFe) MOF led to a remarkable anti-interference ability, even at the interference concentrations of up to 20% glucose, a higher value than that in human serum. In addition, a heat treatment was carried out to remove the residual terephthalic acid in the MOF tunnels, and this promoted the detection linear range to 2-1600 μM. The reusability, reproducibility and long-term stability of the sensors were also studied, and the results implied good practicability of the MIL-53(NiFe) MOF-based sensors. Furthermore, the good practicability of the sensors was verified by testing human serum samples. The results showed the relative standard deviation of 2.73% from the hospital results, and the standard recovery was nearly 100%.

Representing a new type of biodegradable cationic block copolymer, well-defined poly(ethylene glycol)-block-cationic polylactides (PEG-b-CPLAs) with tertiary amine-based cationic groups were synthesized by thiol-ene functionalization of an allyl-functionalized diblock precursor. Subsequently the application of PEG-b-CPLAs as biodegradable vectors for the delivery of plasmid DNAs (pDNAs) was investigated. Via the formation of PEG-b-CPLA:pDNA nanocomplexes by spontaneous electrostatic interaction, pDNAs encoding luciferase or enhanced green fluorescent protein were successfully delivered to four physiologically distinct cell lines (including macrophage, fibroblast, epithelial, and stem cell). Formulated nanocomplexes demonstrated high levels of transfection with low levels of cytotoxicity and hemolysis when compared to a positive control. Biophysical characterization of charge densities of nanocomplexes at various polymer:pDNA weight ratios revealed a positive correlation between surface charge and gene delivery. Nanocomplexes with high surface charge densities were utilized in an in vitro serum gene delivery inhibition assay, and effective gene delivery was observed despite high levels of serum. Overall, these results help to elucidate the influence of charge, size, and PEGylation of nanocomplexes upon the delivery of nucleic acids in physiologically relevant conditions.

In this paper, through a simple and fast electroless metal deposition route, gold dendritic nanostructures are synthesized in aqueous conditions. The gold dendrites with a threefold symmetric characteristic were built up of numerous nanoparticles roughly 5–10 nm in size. The aggregated nanoparticles spontaneously experience a self-assembly process along crystallographic orientations and finally form a monocrystalline dendrite. An oriented attachment mechanism can be used to explain the nanoparticle-aggregated self-assembly process.