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Detrital zircon U Pb geochronology and geochemical proxies derived from immobile elements and isotopes are commonly applied to trace sediment sources because of their durability and stability in most earth surface processes and environments. However, little is known on whether these different tracers can contain identical or similar provenance signals for sediments of interest. This study presents the U Pb ages of detrital zircons from a grain-size fraction of 63–125 μm and elemental and Nd isotopic compositions for bulk sediments from the Mulanxi, a small mountainous river in southeast China. We aim to retrieve provenance signals preserved by different tracers and to test whether they are robust in discriminating the effect of sediment mixing in this tidal-dominated river. Our results show that detrital zircons in the Mulanxi catchments and estuarine have two major age groups at 90–110 Ma and 120–150 Ma. Moreover, the results of probability density plots (PDPs) suggest there is no significant difference in detrital zircon U Pb ages between the sediments from non-tidal and tidal reaches. The detrital zircon age distributions in the Mulanxi catchments are significantly different from those in the Changjiang (Yangtze River) catchments and in the inner shelf mud belt of the East China Sea which have distinct multiple age populations. A statistical multidimensional scaling (MDS) analysis suggests there is no a source-to-sink connection between the Changjiang and Mulanxi zircons. On the contrary, the geochemical proxies of Sc/Th, Cr/Th, and Nd isotopes reveal different sediment sources between the non-tidal and tidal reaches of Mulanxi, with the fine tidal-reach sediments having mixed sources from the offshore mud and the Mulanxi River, while the coarse-grained sediments from the non-tidal upstream being completely contributed by the Mulanxi. The contradictory results from these different provenance proxies suggest their implications and limitations for sediment source tracing. Detrital zircon ages can track the ‘inherited’ source signals of zircons and relating coarse fractions in sediments, but they are less sensitive to source changes in fine fractions than the geochemical proxies of Nd isotopes, Sc/Th and Cr/Th ratios. It is therefore essential and a prerequisite to carefully evaluate all possible factors controlling detrital sediment compositions, and to weigh the pros and cons of different tracers for sediment provenance discrimination especially in dynamic Small Mountainous Rivers (SMRs) and continental margins.

In this study, biomimic porous polycaprolactone/poly (lactide-co-glycolide) loading biphasic tricalcium phosphate (PCL/PLGA-BCP) scaffolds were fabricated successfully by solvent evaporation method. The distribution of biphasic tricalcium phosphate (BCP) in polycaprolactone/poly (lactide-co-glycolide) (PCL/PLGA) scaffold was confirmed by micro-computed tomography (micro-CT) scanning, scanning electron microscope (SEM) observation and Energy-dispersive X-ray Spectroscopy (EDS) analysis. The hydrophilicity of the scaffolds was confirmed by contact angle measurement. In in vitro experiments, proliferation of human bone marrow mesenchymal stem cell (hBMSCs) and its osteoblastic differentiation on scaffold were assessed for 1, 2 and 3 weeks using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, fluorescence observation, hematoxylineosin (HE) staining and real-time polymerase chain reaction (RT-PCR). In in vivo experiments, ossification was observed using micro-CT analysis and histological staining.

Hien A Tran,1–4 Khanh L Ly,4 Kate E Fox,5 Phong A Tran,1–3 Thi-Hiep Nguyen4 1Queensland University of Technology (QUT), Brisbane, Queensland 4001, Australia; 2Interface Science and Materials Engineering Group, School of Chemistry, Physics and Mechanical Engineering, QUT, Brisbane, Queensland, Australia; 3Centre in Regenerative Medicine, QUT, Brisbane, Queensland, Australia; 4Department of Biomedical Engineering, International University, Vietnam National University- Ho Chi Minh City (VNU-HCM), Ho Chi Minh City 70000, Vietnam; 5School of Engineering, Centre for Additive Manufacturing, RMIT University, Melbourne, VIC 3001, AustraliaCorrespondence: Phong A TranQueensland University of Technology (QUT), Brisbane, Queensland 4001, AustraliaTel +61 7 3138 6452Email phong.tran@qut.edu.auThi-Hiep NguyenDepartment of Biomedical Engineering, International University, Vietnam National University- Ho Chi Minh City (VNU-HCM), Ho Chi Minh City 70000, VietnamTel +84 2837 244 270Email nthiep@hcmiu.edu.vnPurpose: The aim of this study is to develop a new coating for wound dressings that is comprised of antimicrobial silver (Ag) and antioxidant flavonoid quercetin (Q).Methods: Dip-coating was used to apply the coating on cotton gauge as a model dressing. Ag was immobilised using polydopamine as a priming and catalytic layer followed by coating of quercetin that was incorporated in a functionalized polydimethylsiloxane. The coating was investigated using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and release assay. The antimicrobial activity of quercetin and Ag was tested against Staphylococcus aureus (S. aureus). A surgical wound model on mice was used to evaluate the effects of the coated dressing on wound healing rates and tissue histology.Results: Ag and quercetin showed enhanced antimicrobial activity against S. aureus when used in combination. Ag and quercetin were successfully immobilized onto the fibre of the dressing using the dip-coating process. The coating released Ag and quercetin over 8 days and showed strong antioxidant activity. In the wound healing model, complete wound closure was achieved in 12 days in the group receiving coated dressing and was associated with an enhancement in tissue remodelling and neo-angiogenesis and the reduction in tissue inflammation.Conclusion: These new antimicrobial-antioxidant coatings may be promising in the development of advanced wound care therapies.Keywords: quercetin, Ag, antioxidant, antibacterial, wound healing

Constructing satisfied small-diameter vascular graft (diameter less than 6 mm) remains an unsolvable challenge in vascular tissue engineering. This study described the fabrication of electrospun polyurethane/polycaprolactone (PU/PCL) membranes chemically grafted with various densities of conjugated linoleic acid (CLA) – an antithrombotic fatty acid – for making small-diameter blood vessel. Differences in mechanical, antithrombotic properties and biocompatibility of the membranes resulting from the CLA-grafting procedure were the focus of the study. Investigation of mechanical properties relevant to vascular graft application revealed that these properties of the membranes remained unaffected and satisfied clinical criteria following the CLA graft. Blood–membrane interaction assays showed that the CLA-grafted membranes mitigated the adhesion of blood cells, as well as preventing blood coagulation. These effects were also commensurate with increasing density of CLA, suggesting an effective approach to improve antithromboticity. Cellular tests suggested that CLA has an optimal density at which it promoted cell proliferation on the surface of the membranes; however, excessive presence of CLA might cause undesirable inhibition on cells. In conclusion, PU/PCL membrane grafted with CLA could be a prospective material for vascular tissue engineering with further development and investigation., Graphical Abstract

This study was aimed to develop a tissue engineering scaffold by incorporation of Bombyx mori silk fiber (BMSF) and agar. This promised the improvement in enhancing their advantageous properties as well as limiting their defects without occurring chemical reactions or crosslink formation. The morphology and chemical structure of scaffolds were observed using scanning electron microscope (SEM) observation and Fourier transform infrared (FT-IR) spectra. The SEM results show that scaffolds containing BMSF have microporous structures, which are suitable for cell adhesion. Agar scaffolds, by contrast, had much more flat morphology. FT-IR spectra confirm that no modifications to BMSF happened in scaffolds, which indicates that there was no chemical reaction or crosslink formation between silk and agar in this process. Furthermore, the biocompatibility of scaffolds was performed in the mouse’s subcutaneous part of the dorsal region for 15 days, followed by Haematoxylin and Eosin (H&E) staining. H&E staining results demonstrate that scaffolds had good biocompatibility and there was no sign of the body rejection in all of samples. The results from animal study show that SA scaffolds have the most stable structure for cell adhesion compared with those single materials.

Polycaprolactone/polyurethane (PCL/PU) fibrous scaffold was loaded with conjugated linoleic acid (CLA) by electrospinning method to improve the hemocompatibility of the polymeric surface. Fourier Transform Infrared Spectroscopy (FT-IR) analysis and Scanning Electron Microscopy (SEM) observation were employed to characterize the chemical structure and the changing morphology of electrospun PCL/PU and PCL/PU loaded with CLA (PCL/PU-CLA) scaffolds. Platelet adhesion and whole blood clot formation tests were used to evaluate the effect of CLA on antithrombotic property of PCL/PU-CLA scaffold. Endothelial cells (EC) were also seeded on the scaffold to examine the difference in the morphology of EC layer and platelet attachment with and without the presence of CLA. SEM results showed that CLA supported the spreading and proliferation of EC and PCL/PU-CLA surface induced lower platelet adhesion as well as attachment of other blood cells compared to the PCL/PU one. These results suggest that electrospinning method can successfully combine the antiplatelet effects of CLA to improve hemocompatibility of PCL/PU scaffolds for applications in artificial blood vessels.

A novel injectable hydrogel that was synthesized by in situ crosslinking of hyaluronan and polyvinyl phosphonic acid was proposed in this study. Fourier transform infrared spectrum (FT-IR) analysis, scanning electron microscope (SEM), pH measurement, and biodegradation test were used to confirm its characteristics. The results permitted to prove successful crosslinking, observe the inner morphology of hydrogel and pore sizes distribution, and determine the decomposition of hydrogel components during incubation time. Result of pH measurement showed that the pH scale of hydrogel decreased when volume of PVPA increased. As a consequence, it affected the cytotoxicity value, cell proliferation, and cell growth behaviors of each hydrogel. Optical microscope observation showed that chondroblasts cell proliferated well on HA-PVPA hydrogel. Therefore, these results suggest that the new injectable hydrogel is appropriate for bone/cartilage regeneration applications.

In this study, electrospun polycaprolactone membrane coated with chitosan-silver nanoparticles (CsAg), electrospun polycaprolactone/chitosan/Ag nanoparticles, was fabricated by immersing the plasma-treated electrospun polycaprolactone membrane in the CsAg gel. The plasma modification of electrospun polycaprolactone membrane prior to CsAg coating was tested by methylene blue stain and scanning electron microscope. The presence of silver and chitosan on the plasma-treated electrospun polycaprolactone membrane was confirmed by energy-dispersive X-ray spectroscopy and FT-IR spectrum. Scanning electron microscope observation was employed to observe the morphology of the membranes. The release of Ag ions from electrospun polycaprolactone/chitosan/Ag nanoparticles membrane was tested using atomic absorption spectrometry. Electrospun polycaprolactone/chitosan/Ag nanoparticles membrane inherited advantages from both CsAg gel and electrospun polycaprolactone membrane such as: increasing biocompatibility, mechanical strength, and antibacterial activity against both Gram-negative and Gram-positive bacteria. Thus, this investigation introduces a highly potential membrane that can increase the efficacy of the wound dressing process.

In this work, Simvastatin (SIM) loaded porous poly(lactic-co-glycolic acid) (PLGA) microspheres were fabricated using the W/O/W1/W2 double emulsion and solvent evaporation method. The optimal conditions for fabricating porous PLGA microspheres were determined to be 20% distilled water (v/v), 10% PLGA (m/v), and a 4:1 ratio of internal polyvinyl alcohol (PVA) to dichloromethane (DCM). The pores size distribution of porous PLGA microspheres was varied from 0.01 to 40 μm, while their particle displayed a bimodal size distribution that had two diameter peaks at around 100 μm and 500 μm. The SIM encapsulation efficacy was found to be very high with a yield near 80% and the porous PLGA microspheres showed the excellent biocompatibility. In addition, the drug release profile was found to be significantly different from a temporal basis. Base on the combined results of this study, SIM loaded PLGA microspheres holds great promise for use in biomedical applications, especially in drug delivery system or tissue regeneration.

In this study, an electro-spun co-polymer PLGA/PCL blend was fabricated using various percentages of PLGA in the blend PLGA/PCL solutions. The PLGA/PCL ratios used to fabricate the electrospun fibrous mats were reflected in the FT-IR (Fourier Transform Infrared Spectroscopy) data. Experimental results from the MTT assay showed that the biocompatibility of the electro-spun co-polymer increased at increasing percentages of PLGA. In vitro cells adhesion and proliferation of fibroblast cells on electro-spun mats were characterized by SEM morphology. In addition, we found that increasing PLGA concentrations affected the mechanical properties of electro-spun membranes and increased the biocompatibility of PLGA/PCL electro-spun fibrous mats.