Advances in Application of Environmental-friendly Seaweed Polysaccharide Biomaterials

Seaweed polysaccharides are a type of natural high-molecular active substances extracted and purified from seaweed. They are formed from different mon- esaccharide units through glucosidic bonds, with the advantages of high viscosity, good gel property, environmental-friendly and low cost. In this review, we focus on the progress of the application of seaweed polysaecharides in the fields including food, medicine, tissue engineering and environment engineering, where seaweed polysaccharides are used as food additives, edible coating materials, drug-release materials, medical dressing, tissue scaffolds and environmental adsorption materi- als. Introducing special properties, such as targeting, electrical conductivity and thermasensitivity, and designing bionic controllable micro/nanostructures to fabri- cate and develop multi-functional, intelligent seaweed polysaccharides would be the research hotspot in the future.

Transient Expression of VHB and GLUT1 in the Green Alga Haematococcus pluvialis Using Agrobacteriummediated Transformation

The first successful Agrobacterium-mediated transformation of the green alga Haematococcus pluvialis using the vectors hosting the genes coding for VHB （ Vitreoscilla hemoglobin） and GLUT1 （glucose transporter 1 ） is reported here. The greenish yellow fluorescence of EGFP was observed when the zeocin-resistant cells were viewed with a fluorescent microscope. The functional expression of EGFP showed that the Agrobacterium-mediated transformation could efficiently transfer the exogenous gene into H. pluvialis. RT-PCR was used to successfully amplify the mRNA of VHB and GLUT1 genes from transformed cells, while Southern blots indicated the integration of VHB and GLUT1 genes into the genome of H. pluvialis. Transferring VHB and GLUT1 genes into this alga would pave the way for manip- ulation of many important pathways relevant to the food, pharmaceutical, and nutraceutical industries.

Vitreoscilla hemoglobin gene(vgb)improves lutein production in Chlorella vulgaris

Vitreoscilla hemoglobin is an oxygen-binding protein that promotes oxygen delivery and reduces oxygen consumption under low oxygen conditions to increase the effi ciency of cell respiration and metabolism.In this study,we introduced a Vitreoscilla hemoglobin gene(vgb)into Chlorella vulgaris by Agrobacterium tumefaciens-mediated transformation(ATMT).PCR analysis confi rmed that the vgb gene was successfully integrated into the Chlorella vulgaris genome.Analysis of biomass obtained in shake fl asks revealed transformant biomass concentrations as high as 3.28 g/L,which was 38.81% higher than that of the wild-type strain.Lutein content of transformants also increased slightly.Further experiments recovered a maximum lutein yield of 2.91 mg/L from the transformants,which was 36.77% higher than that of the wild-type strain.The above results suggest that integrated expression of the vgb gene may improve cell growth and lutein yield in Chlorella vulgaris,with applications to lutein production from Chlorella during fermentation.

Design and Fabrication of Functional Hydrogels through Interfacial Engineering

Hydrogels have drawn considerable attention in the past two decades due to their excellent biocompatibility and multi-stimuli responsiveness. They have a wide range of applications in the fields related to tissue engineering, sensors and biomedicine. Their applications are strongly influenced by the surface properties of hydrogels and the interfacial interactions between hydrogels and other substrates. In particular, the surface wettability and adhesion of hydrogels decide their applications as drug carriers and wound dressing materials. Nevertheless, there is a lack of systematic discussion on the surface functionalization strategies of hydrogels. Therefore, this review aims at summarizing the strategies of functionalizing the surfaces of hydrogels and bonding hydrogels with other solid substrates. It also explores the challenges and future perspectives of interfacial engineering of hydrogels.

Rapid Determination of Tetrodotoxin in Human Plasma by Ultra Performance Liquid Chromatography-Tandem Mass Spectrometry

A sensitive analytical method was developed to determine tetrodotoxin（TTX） in human plasma samples using protein precipitation, followed by ultra performance liquid chromatography（UPLC） analysis coupled with tandem mass spectrometry（MS/MS） using 11-deoxytetrodotoxin（11-deoxyTTX） as an internal standard. The plasma samples were prepared using protein precipitation prior to being analyzed by UPLC-MSfMS to identify TTX over a zwitterionic-hydrophilic interaction liquid chromatography column. The retention time values of TTX and 11-deoxyTTX were 4.12 and 3.67 min, respectively. TTX and 11-deoxyTTX were monitored and quantitated on the basis of their ion transitions for their respective precursor ions to their product ions（i.e., m/z 320.0→162. l for TTX and m/z 304.0→176.0 for 11-deoxyTTX） in the multiple reaction-monitoring mode. The lower limit of quantification of this method was determined to be 0.0199 ug/mL. This method showed good linearity for plasma samples that contained TTX concentrations in the range of 0.0199--1.99 ng/mL. The specificity, precision, accuracy, matrix effect, and stability characteristics of this method were also examined. The intra-assay precision and accuracy ranged from 1.89% to 6.00% and from 92.21% to 100.00%, whereas the inter-assay precision and accuracy ranged from 0.64% to 7.75% and from 99.38% to 101.26%, respectively. This new method therefore represents a rapid, accurate, reliable, and highly sensitive method for the qualitative and quantitative analyses of a trace amount of TTX in human plasma samples.

Nonswellable hydrogels with robust micro/nano-structures and durable superoleophobic surfaces under seawater

Hydrogels, composed mainly of water trapped in three dimensional cross-linked polymer networks, have been widely utilized to construct underwater superoleophobic surfaces. However, the swelling nature and instability of hydrogels under complex marine environment will weaken their underwater superoleophobicity. Herein, we synthesize structured poly(2-hydroxyethylmethacrylate)(PHEMA) hydrogels by using sandpaper as templates. The robust non-swelling of PHEMA hydrogel ensures that micro/nano-structures on the surface of PHEMA hydrogels can be well maintained. Moreover, when roughness Ra of about 3~4 μm, the surface has superior oil-repellency. Additionally, even after immersing in seawater for one-month, their breaking strength and toughness can be well kept. The non-swellable hydrogels with long-term stable under seawater superoleophobicity will promote the development of robust superoleophobic materials in marine antifouling coatings,biomedical devices and oil/water separation.