The current status of biotechnological production and the application of a novel antioxidant ergothioneine.

Ergothioneine is a sulfur-containing histidine derivative, that possessesexcellent antioxidant activity and has been used in the food and cosmetics industries. It plays a significant role in anti-aging and the prevention of various diseases. This review will briefly introduce the functions and applications of ergothioneine, elaborate the biosynthetic pathways of ergothioneine and describe several strategies to increase the production of ergothioneine. Then the efficient extraction and detection methods of ergothioneine will be presented. Finally, several proposals are put forward to increase the yield of ergothioneine, and the development prospects of ergothioneine will be discussed.

Regeneration Mechanism of Sulfur Absorption Via Samarium-doped Cerium Adsorbents in the Gas Atmosphere of O2/N2.

Sulfides existing in many high-temperature gas mixtures have a negative effect on various industrial applications. Ce-based adsorbents are becoming a hotspot in the high-temperature desulfurization process owing to their excellent thermal stability at high temperatures and regeneration capacity. In this study, we investigate the regeneration path of samarium-doped cerium (SDC) sorbent at high temperature. The SDC adsorbent showed a good sulfur removal ability and excellent regeneration capacity. Ce2O2S and Ce(SO4)2 are observed in the used adsorbent, and Ce2O2S is the main sulfur-containing species. The regeneration path of the Ce2O2S is the key to the regeneration mechanism of the adsorbent. There are two regeneration paths for the Ce2O2S at high temperature in O2/N2 gas mixture. In air stream, the Ce2O2S is oxidized to Ce2O2SO4 and then decomposes into CeO2 and SO2. In a 2% O2/N2 gas condition, the Ce2O2S directly generates CeO2 and elemental sulfur with O2 assistance.

All-Organic Conductive Biomaterial as an Electroactive Cell Interface.

Various attractive materials are being used in bioelectronics recently. In this paper, hydroxymethyl-3,4-ethylenedioxythiophene (EDOT-OH) has been in situ integrated and polymerized on the surface of the regenerated silk fibroin (RSF) film to construct a biocompatible electrode. In order to improve the efficiency of in situ polymerization, sodium dodecyl sulfate (SDS) was adopted as surfactant to construct a well-organized and stable poly(hydroxymethyl-3,4-ethylenedioxythiophene) (PEDOT-OH) coating, whereas ammonium persulfate was used as oxidant. The effects of dosages of surfactant and oxidant, initial pH value, and monomer concentration on the polymerization were studied. Under the optimal conditions, the RSF/PEDOT-OH film exhibited a square resistance of 3.28 × 105 Ω corresponding to a conductance of 6.1 × 10-3 S/cm. Scanning electron microscope images indicated that PEDOT-OH was deposited uniformly on the surface of the RSF film with SDS. Furthermore, Fourier transform infrared spectroscopy confirmed that interactions existed between the peptide linkages of silk fibroin (SF) macromolecules and PEDOT-OH. The RSF/PEDOT-OH film displayed favorable electrochemical stability, biocompatibility, and fastness. This study provides a feasible method to endow conductivity to RSF materials in various forms. In addition, the conductive layer and biocompatible silk substrate make the RSF/PEDOT-OH biomaterial highly suitable for potential applications in bioelectric devices, sensors, and tissue engineering.

Characterization of bladder acellular matrix hydrogel with inherent bioactive factors.

Bladder acellular matrix (BAM) hydrogel may have great potential in tissue engineering due to outstanding biocompatibility and the presence of inherent bioactive factors in BAM. In this study, we prepared the BAM hydrogel by the method of enzymatic solubilization with pepsin and characterize the microrheological properties of the BAM precursor solution. The structures of the BAM hydrogel were characterized by scanning electron microscope (SEM), Fourier-transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). Furthermore, the growth factors including vascular endothelial growth factor (VEGF), platelet-derived growth factor B (PDGF-BB), keratinocyte growth factor (KGF) were quantified by ELISA. The biological performances of the hydrogels were evaluated by cultivating porcine iliac endothelial cells (PIECs) in vitro. Lyophilized BAM showed porous structure with pore diameter ranging from 50 to 100µm. BAM 4-G hydrogel (4mg/mL) with a short gelation time of 3.95±0.07min presents better thermal stability than BAM 6-G hydrogel (6mg/mL). Growth factors in the BAM hydrogel maintain valuable biological activity even after digestion process. The BAM hydrogel supported the adhesion and growth of PIECs well and has great potential for further tissue engineering.

Significantly reinforced composite fibers electrospun from silk fibroin/carbon nanotube aqueous solutions.

Microcomposite fibers of regenerated silk fibroin (RSF) and multiwalled carbon nanotubes (MWNTs) were successfully prepared by an electrospinning process from aqueous solutions. A quiescent blended solution and a three-dimensional Raman image of the composite fibers showed that functionalized MWNTs (F-MWNTs) were well dispersed in the solutions and the RSF fibers, respectively. Raman spectra and wide-angle X-ray diffraction (WAXD) patterns of RSF/F-MWNT electrospun fibers indicated that the composite fibers had higher ß-sheet content and crystallinity than the pure RSF electrospun fibers, respectively. The mechanical properties of the RSF electrospun fibers were improved drastically by incorporating F-MWNTs. Compared with the pure RSF electrospun fibers, the composite fibers with 1.0 wt % F-MWNTs exhibited a 2.8-fold increase in breaking strength, a 4.4-fold increase in Young's modulus, and a 2.1-fold increase in breaking energy. Cytotoxicity test preliminarily demonstrated that the electrospun fiber mats have good biocompatibility for tissue engineering scaffolds.

Synthesis and release studies of microalgal oil-containing microcapsules prepared by complex coacervation.

Microalgal oil was encapsulated in gelatin-gum Arabic complex coacervated matrices using transglutaminase (TG) as cross-linking agent. The effects of various cross-linking parameters including hardening time, temperature, pH and TG concentration on the oil release rate of the complex coacervation microcapsules (CCMs) were investigated, with sodium dodecyl sulfate (SDS) as release medium. The optimum parameters were as follows: hardening for 6h at 15°C and pH 6.0 with TG concentration of 15 U/g gelatin. The microcapsules obtained under optimum conditions had the lowest oil release rate. By analyzing the oil release curves, it was found that the oil release rate did not exactly fit the modified first-order kinetic model but exhibited early time and late time approximations for unsteady state diffusion. A greater initial release of oil was clearly observed whatever cross-linking parameters were, while the release profile became constant indicating some sustained release after the first hour.

Characterization of spray-dried microalgal oil encapsulated in cross-linked sodium caseinate matrix induced by microbial transglutaminase.

Sodium caseinate (SC) cross-linked by microbial transglutaminase (MTGase) for encapsulating microalgal oil was investigated. Protein cross-linking was evidenced in the SDS-PAGE graph. The emulsifying properties of SC depended on the cross-linked time with MTGase. The emulsifying activity and stability indexes of SC increased with the cross-linking time of 30 to 90 min (P30 to P90), and then declined with longer cross-linked time of 180 to 420 min (P180 to P420). The P30 to P90 as wall material for microencapsulation was superior to P180 to P420 and control sample. The microcapsules prepared with P30 to P90 showed more than 97% of microencapsulation efficiency in contrast to about 90% with the P180 to P420. During storage, the microcapsules prepared with P30 to P90 exhibited higher oxidative stability as compared with other microcapsules. A sustained release of microalgal oil was observed, and core release was time dependent and affected by cross-linking degree. Results showed that the powdered microalgal oil prepared with P30 to P90 demonstrated enhanced physicochemical properties and oxidative stability. Practical Application: The novel method using cross-linked proteins as wall material induced by microbial transglutaminase in food industry for sensitive ingredients could convert microcapsules into a stable form, which would lead to its more widespread utilization as a kind of food additive.