Metarhizium robertsii, a butyltin-resistant filamentous fungus, can rapid and complete biodegradation of di- (DBT) and tributyltin (TBT) under conditions of intensive aeration and ascorbic acid supplementation. In this paper, lipidomic investigations were performed to find the membrane adaptations necessary for effective butyltins degradation. HPLC-MS/MS analysis showed that the phospholipid profile was greatly modified during M. robertsii batch cultivation (pO2 ≥ 20%), contributing to increased membrane fluidity and facilitated mass transfer, which could enhance butyltins biodegradation. Intensified biosynthesis of phospholipids, sphingolipids and ergosterol by the mycelia exposed to butyltins was noted. DIOC6(3) fluorescence intensity for TBT-treated mycelium increased 9-fold pointing to membrane hyperpolarization. Fluorescent studies showed improved membrane rigidity and integrity in response to butyltins presence. Vitamin C supplementation restored membrane composition and dynamic properties, followed by supposed acceleration of transport of monobutyltin and its biodegradation thus protecting the M. robertsii cells against oxidative and nitrosative stress.

In this work, the three-dimensional nitrogen-doped nanostructured carbons with hierarchical architectures (3D-NNCsHAs) with high density of defective sites, high surface area and pluralities of pore size distributions was prepared through the pyrolysis of sea-tangle (Laminaria japonica), an inexpensive, eco-friendly and abundant precursor. Benefitting from their structural uniqueness, a selective and sensitive ascorbic acid (AA) sensor based on 3D-NNCsHAs was developed. Compared to the glassy carbon electrode (GCE) and the carbon nanotubes modified GCE (CNTs/GCE), the 3D-NNCsHAs modified GCE (3D-NNCsHAs/GCE) presents higher performance towards the electrocatalysis and detection of AA, such as lower detection limit (1 μM), wider linear range (10-4410 μM) and lower electrooxidation peak potential (-0.02 V vs. Ag/AgCl). In addition, 3D-NNCsHAs/GCE also exhibits high anti-interference and anti-fouling abilities for AA detection. Particularly, the fabricated 3D-NNCsHAs/GCE is able to determine AA in real samples and the results acquired are satisfactory. Therefore, the 3D-NNCsHAs can be considered as a kind of novel electrode nanomaterial for the fabrication of selective and sensitive AA sensor for the extensive practical applications ranging from food analysis, to pharmaceutical industry and clinical test.

Phospholipid nanoparticles (PNs) encapsulating vitamin C and E derivatives, 3-O-cetyl ascorbic acid (CA) and tocopherol acetate (TA), respectively, were examined using the film rehydration and extrusion method. PN formulations (TA-Cassome) were prepared by mixing CA, soya phosphatidylcholine (Soya PC), sodium cholate, and TA at a molar ratio of 20/80/5/6. Glycerol (GL) or diglycerol (DG) were also added to improve the skin accumulation of CA and TA. Three TA-Cassome formulations were evaluated using a dynamic light scattering (DLS), NMR, TEM, skin accumulation test for CA and TA, and small-angle X-ray diffraction (SAXD) analysis. TA-Cassome formulations (150 nm) were stable for two weeks and they encapsulated 1.8 mg/mL of TA. TEM and SAXD analysis revealed that the nanoparticles formed a spherical multilayer structure. 1H and 31P NMR indicated that GL and DG enhanced the proton mobility of choline groups of soya PC molecules located on the membrane surface of TA-Cassome. Accumulation of CA and TA in the dermis was increased by adding GL and DG. SAXD analysis revealed that GL and DG promoted the formation of new lamellar structures on the stratum corneum, which contributed to improving the skin accumulation of CA and TA.

The use of alkaline phosphatase (ALP) as a biomarker in some diseases including hepatitis, obstructive jaundice, osteoblastic bone cancer, and osteomalacia is important in clinical diagnosis. Furthermore, ALP activity detection is an essential hot topic in environmental monitoring, biomedical research, and other research fields. In this study, a novel "signal-on" photoelectrochemical (PEC) biosensor based on the ALP-catalyzed phosphorylation reaction was designed to sensitively detect ALP activity. In this design, ascorbic acid-an electron donor-was catalytically produced by ALP from l-ascorbic acid 2-phosphate trisodium salt in situ, which results in an increased photocurrent response signal. For immobilizing the ALP on the electrode surface, poly diallyl dimethyl ammonium chloride was used for the conjugation of ALP, and titanium dioxide (TiO2)-a photoactive material-and graphite-like carbon nitride (g-C3N4) nanocomposites were prepared and characterized. TiO2 attached on g-C3N4 plays an important role for the biosensing purpose due to their good biocompatibility and chemical/thermal stability, while g-C3N4 provides the PEC response signal. Furthermore, the prepared TiO2/g-C3N4 nanocomposites can effectively suppress electron-hole recombinations, improve the excitation conversion efficiency, and make the best use of solar energy. The PEC biosensor for ALP activity detection displays a detection limit of 0.03 U L-1 (S/N = 3), which offers a new route for the ALP activity assay in human serum samples.

A study on the electrochemical oxidation of piperazine and its electrochemical copolymerization with aniline in acidic medium is presented. It was found that the homopolymerization of piperazine cannot be achieved under electrochemical conditions. A combination of electrochemistry, in situ Fourier transform infrared (FTIR), and ex situ X-ray photoelectron spectroscopy (XPS) spectroscopies was used to characterize both the chemical structure and the redox behavior of an electrochemically synthesized piperazine⁻aniline copolymer. The electrochemical sensing properties of the deposited material were also tested against ascorbic acid and dopamine as redox probes.

The paper-based analytical device (PAD) was applied in this study to analyze the antioxidant activity of Danhong injection and its intermediates. First polycaprolactone was printed on the surface of a filter paper with a 3D printing device. The modified filter paper was then prepared using polycaprolactone and solid paraffin as the modifiers. The PAD was prepared after adding DPPH ethanol solution to the modified filter paper. Ascorbic acid solutions with different concentrations were used as the positive drug on PAD. After the occurrence of color reactions, the PAD was dried, and the data of color were collected by a cell phone. The color component G and grayscale were selected as the potential indices for measurement according to the values of determination coefficients, detection limits, and effective number of digits. Qualitative and quantitative analysis of Danhong injection and the concentrate of aqueous extract were realized with the PAD. Because no significant differences were observed between the results obtained using the two potential indices, the average values of these two were used for analysis, and the antioxidant activity of Danhong injection and the concentrate of aqueous extract was equivalent to ascorbic acid solutions of 3.7, 46 g·L⁻¹, respectively. The PAD method presented in this work can be a simple method to determine biological activities of Chinese medicines and their intermediates.

Furan derivatives, potentially carcinogenic to humans, can be formed, in addition to carbohydrates and other sources, from the degradation of ascorbic acid (AA). At present, the mechanisms involved in the ascorbic acid degradation are not yet fully understood. In this study, we reported a gas-phase investigation, performed using Triple Quadrupole (TQ/MS) and Ion Trap Mass Spectrometry (QIT/MS) together with quantum mechanical calculations at the B3LYP/6-31+G(d,p) level of theory, on the non-oxidative degradation mechanism of l-ascorbic acid (AA) to furan derivatives. Gaseous protonated ascorbic acid ions, the AAH+ ionic reagents, were generated by Electrospray Ionization (ESI) of an aqueous AA solution added with a mild protonation reagent. The Collisionally Induced Dissociation (CID) mass spectra of the AAH+ ions displayed gaseous fragment ions corresponding to the degradation intermediates and reaction products, which were structurally characterized and identified. Precise mechanistic insights were achieved by using l-[1-13C]-AA. On the basis of experimental and computational results, the gas phase non-oxidative acid catalyzed degradation mechanism of ascorbic acid is proposed, a benchmark point for the comprehension of the mechanism in the condensed phase.

Ocular chemical burns are common and serious ocular emergencies which require immediate and intensive evaluation and treatment. Loss of vision and disfigurement affect the victims, bringing great sufferings to themselves and their families. China is the biggest developing country in the world with a large number of such cases. The prevention of ocular chemical burns is emphasized in different aspects. After emergency treatment, proper care of chemical burns is started by control of inflammation with corticosteroids. Topical and systemic ascorbic acid supplement is important. Re-epithelialization is critical to stabilize the ocular surface and to prevent corneal ulceration and melting. The goal of treatment is mainly to restore the ocular structure and function. Neuroprotection is important during the treatment course for control of both glaucoma and inflammation. Prognosis depends on the degree of limbal, corneal and conjunctival involvement at the time of injury as well as the management. Medical treatments only or with combination of surgical procedures, including amniotic membrane transplantation, epithelial or limbal stem cell transplantation, tenonplasty, keratoplasty and keratoprosthesis, are according to the classification of ocular chemical burns and the phases. Further investigations should be done in the future in both prevention and management of ocular chemical burns in China. (Chin J Ophthalmol, 2018, 54: 401-405).

Pico sized Stannous oxide particles (SnO PPs) were synthesized in an ethanol-water solvent system on the surface of nitrogen doped graphene oxide (GO). The highly conductive support was a combination of dual interactions between 4-aminomethylbenzylamine (AMBA) and GO. The oppositely positioned -NH2 linkers of the AMBA were covalently incorporated into the GO matrix through condensation reaction followed by the strong π - π stacking interactions between aromatic rings of AMBA and GO. The change in the local chemical environment of GO via dual interactions provided a suitable atmosphere for the growth and dispersion of SnO PPs on GO-AMBA surface. The possible mechanism for the formation of SnO in an ethanol-water solvent system was evaluated. Furthermore, a light was shed on the factors responsible for the pico size of SnO particles synthesis along with its phenomenal distribution on the GO-AMBA surface. The catalyst containing SnO PPs was deployed as a biosensor for the detection of ascorbic acid (AA) for the very first time. A very wide linear range of 5.0 × 10-5-7.0 × 10-3 M, limit of detection (LOD) of 1.19 × 10-5 M along with excellent practical feasibility, storage stability, repeatability and selectivity towards AA electrooxidation showed the excellent synergy between nitrogen-rich GO surface and SnO PPs. The sensitivity (885.54 µAmM-1cm-2) of the catalyst was the most attractive feature, as it was obtained in the presence of 5 and 2-fold higher concentration of UA and DA interfering species respectively.