Dental implants have great potential in the global market, around $3.7 billion in 2015, which will increase to $7 billion in 2023 with an annual increase rate of 8.2%. Incorporating antibacterial and osteogenic agents into implants is helpful to make the dental implants successful, which can be endowed by coatings. In recent years, graphene oxide (GO) and its composite materials have shown advances in the biomedical field. Lysozyme (Lys) and tannic acid (TA) are naturally derived, with promising antibacterial and osteogenic properties as well. In the present study, the strong antibacterial and enhanced osteogenic multilayer coating is fabricated using the facile and controllable layer by layer (LBL) technique to integrate GO, Lys, and TA. The thickness of coating exhibited a continuous growth with the deposited process as proved from UV−vis and ellipsometry data, and the physical properties of the coating, such as wettability, roughness, and stiffness are well characterized. The coatings exhibited the synergic effect on the killing bacteria, both Gram-negative bacteria and Grampositive bacteria represented by E. coli and S. aureus, respectively, and enhancing osteogenesis of dental pulp stem cells (hDPSCs), showing the potential application on coatings of dental implants. Thus, the strategy applied here will inspire the design and development of dual functional surfaces for the success of implanted dental surface in future.

Though the effects of scaffold properties such as stiffness and topography on stem cell behavior was well known of, there were multiple theories that explain such behavior and there has been no common consensus thus far. This study deals with using polydimethylsiloxane (PDMS) to mimic a specific microenvironment that favors human mesenchymal stem cells (hMSCs) differentiation into myogenic lineages through the manipulation of specific surface topography and appropriate substrate stiffness. Femtosecond laser was applied to machine microchannels on PDMS substrates in this work. hMSCs were seeded and cultured on lasercut substrates, uncut substrates and controls. Quantitative and qualitative analyses of stem cell behavior were discussed herein with the use of Picogreen Assay for cell proliferation, staining of cytoskeleton for cell orientation, immunostaining of Myosin Heavy Chain for a myogenic biomarker, and quantitative real time polymerase chain reaction for gene expression analysis. It was found that both myogenic differentiation of hMSCs could be achieved by moderate stiffness or microchannels. And differentiation was further boosted by such PDMS substrates with additional microchannels.

In the study, PS/Ag composite microspheres with polystyrene (PS) core and silver shell were synthesized by ultrasonic electroless plating. The samples were characterized by SEM, FTIR and XRD. The effects of times of sensitization and silver plating, mass ratio of AgNO3 to PS microspheres and stirring method on the preparation and dispersion of PS/Ag microspheres were studied. The results show that the more times of sensitization and silver plating, the more uniform the silver deposition on the surface of microspheres. When the mass ratio of AgNO3 to PS microspheres is 2: 1, it can promote the uniform coating of silver shell and reduce the content of free silver. Ultrasonic assisted electroless plating for 10 min can prevent PS/Ag microspheres from agglomerating and improve the speed of electroless plating. The thickness of the silver shell on the surface of the PS microsphere is about 200 nm.

Background To date, triple-negative breast cancer (TNBC) treatment options are limited because of the loss of target receptors and, as a result, are only managed with chemotherapy. What is worse is that TNBC is frequently developing resistance to chemotherapy. By using small interfering RNA (siRNA)-based therapeutics, our recent work demonstrated X-box-binding protein 1 (XBP1) was linked to human epidermal growth factor receptor 2 positive (HER2+) breast cancer development and chemoresistance. Given the instability, off-target effects, net negative charge, and hydrophobicity of siRNA in vivo utilization and clinical transformation, its use in treatment is hampered. Thus, the development of a siRNA-based drug delivery system (DDS) with ultra-stability and specificity is necessary to address the predicament of siRNA delivery.Results Here, we assembled RNase resistant RNA nanoparticles (NPs) based on the 3WJ structure from Phi29 DNA packaging motor. To improved targeted therapy and sensitize TNBC to chemotherapy, the RNA NPs were equipped with an epidermal growth factor receptor (EGFR) targeting aptamer and XBP1 siRNA. We found our RNA NPs could deplete XBP1 expression and suppress tumor growth after intravenous administration. Meanwhile, RNA NPs treatment could promote sensitization to chemotherapy and impede angiogenesis in vivo.Conclusions The results further demonstrate that our RNA NPs could serve as an effective and promising platform not only for siRNA delivery but also for chemotherapy-resistant TNBC therapy.

Correction for ‘Self-template synthesis of hierarchical CoMoS3 nanotubes constructed of ultrathin nanosheets for robust water electrolysis’ by Jinxue Guo et al., J. Mater. Chem. A, 2017, DOI: 10.1039/c7ta02768k.

Due to the high conductivity and stability of silver, silver ink has been widely used in the field of printed electronics. However, since mechanical strain would cause the contact between key particles to be broken. Recently, higher requirements have been put on the bending resistance of silver paste. In this experiment, by preparing Ag NPs: Ag Flakes composite materials of 20:80 and 30:70 respectively, a new method for preparing stable modified flake silver powder is proposed, and the attachment and growth methods of Ag NPs reduced on micron flake silver powder is discussed. Flake silver powder, dispersant and reducing agent are added to the silver-ammonia complex, and the nano-silver particles are reduced on the flake silver powder by controlling the reaction conditions. When Ag+: Ag Flakes in the solution is 30:70, there is a clear interface between the silver particles and the silver flakes, and the size distribution range is between 10 and 100 nm; when Ag+: Ag Flakes is 20:80, the distance between the nano-silver particles and the silver plate crystal plane is about 0.222 nm and 0.260 nm, these spacings represent the (1–12) and (004) planes of Ag, respectively. The reduced silver particles grow on the surface of the silver sheet, the size is about 5 ∼ 60 nm, and form a sheet-point combination of shaped silver powder, which can be used to make conductive silver paste with cost and performance competitiveness. The reaction can be completed at room temperature (5 ∼ 25 °C) and atmospheric pressure (80 ∼ 100 kPa), the operation is simple, the reaction time is short, and it has a positive effect on the commercial production of printable highly conductive silver paste.

Ordered porous films were prepared by the breath figure method based on self-synthetic polystyrene-b-polyacrylonitrile (PS-b-PAN). Their morphologies were characterized by scanning electron microscopy. The influence of polymer concentration, solvent, and polymer structure on the structures of porous films was investigated. Film surfaces were covered with round hexagonally packed pores, and a honeycomb structure resided under film surfaces. With increasing polymer concentration in the chloroform (CHCl3) solvent, pore spacing increased and the size of honeycomb structure decreased. Multilayer structures were observed at higher concentration. When better volatile carbon disulfide (CS2) was instead used as the solvent, even highly ordered porous films were produced. Pore diameter and pore spacing increased, and the size of the honeycomb structure decreased. When the polystyrene macro-initiator (PS-Cl) without PAN blocks was adopted as the film material, nest-like structures instead of pores were formed on the film surface. The halo on the film surface suggests that when water droplets were positioned under the liquid film, defects formed on the film surface.

A new triazine charring agent, melamine formaldehyde resin modified with pentaerythritol (named as MF-MPOL), was synthesized through hydroxymethylation, condensation and etherification by using melamine, paraformaldehyde and pentaerythritol as raw materials, and characterized by solid-state 13C NMR and FT-IR. The intumescent flame retardant (IFR) consisting of MF-MPOL with ammonium polyphosphate has good flame retardancy in polypropylene (PP). The analysis of the residues obtained in cone calorimetry test showed that the IFR played a role of flame retardancy mainly in condensed phase. In other words, the porous and dense - continuous intumescent char layer formed during the burning process results in flame retardant effect by insulation of heat, oxygen and preventing the underlying PP from degradation and volatilization of pyrolytic products.