Aptamer-conjugated graphene oxide-based surface assisted laser desorption ionization mass spectrometry for selective extraction and detection of Aß1-42 in an Alzheimer's disease SH-SY5 cell model.

The generation and accumulation of amyloid-beta peptide (Aß1-42) in amyloid plaques are key characteristics of Alzheimer's disease (AD); thus, specific detection of Aß1-42 is essential for the diagnosis and treatment of AD. Herein, an aptamer-conjugated graphene oxide (Apt-GO) sensor was synthesized by π-π and hydrophobic interactions using thiol poly (ethylene glycol) amine (SH-PEG-NH2) as a spacer unit. Then, it was applied to selective capture of Aß1-42, and the resulting complex was directly analyzed by surface-assisted laser desorption ionization mass spectrometry (SALDI-MS). The results revealed that the Apt-GO could enhance the detection specificity and reduce non-specific adsorption. This method was validated to be sensitive in detecting Aß1-42 at a low level in human serum (ca. 0.1 µM) within a linear range from 0.1 to 10 µM. The immobilizing amount of aptamer on the GO was calculated to be 36.1 nmol/mg (RSD = 11.5%). In conclusion, this Apt-GO-based SALDI-MS method was sensitive and efficient in selective extraction and detection of Aß1-42, which proved to be a good option for early AD diagnosis.

Fabrication and characterization of tea polyphenol W/O microemulsion-based bioactive edible film for sustained release in fish floss preservation.

A coated nanoemulsion (CNE)-based edible film was fabricated on the surface of fish floss (FF) to extend its shelf life during storage. The antioxidant tea polyphenol (TPP) was embedded into W/O microemulsion, which was further encapsulated into multiple emulsion (Multi-E) together with functional soluble dietary fiber (SDF). The physicochemical properties indicated that the nanoemulsion-based edible film (NEF) improved the morphology of FF and reduced the crystallinity of the film by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The water vapor permeability increased gradually and rose to only 0.99% after 5 h, resulting in the water activity of FF at a low level (≤0.51) during the storage period. The TPP inside was released at a constant rate (≤18.10%) on the surface, and such a rate was accelerated in the simulated gastrointestinal environment, especially in intestine reaching 60.12% after 5 h of digestion. Besides, the effect of NEF on the flavor was also evaluated and the contents of ketones, phenols, and pyrazines increased, which displayed a regulating effect on the overall flavor of FF by blocking the external moisture and suppressing the microorganism activity. In summary, the NEF effectively enhanced the flavor and taste of FF, controlled the release of TPP, and reduced the water activity during the storage, thereby extending the shelf life.

Effect of steam explosion pretreatment on the composition and bioactive characteristic of phenolic compounds in Chrysanthemum morifolium Ramat cv. Hangbaiju powder with various sieve fractions.

Steam explosion (SE) pretreatment is an efficient technique to promote the fiber degradation and disrupt materials' cell wall. In this study, the effect of SE pretreatment on the changes in phenolic profile, and the in vitro digestion property of a Chinese indigenous herb "Hangbaiju" (HBJ) powder with various sieve fractions (150-, 180-, 250-, 425-, and 850-µm sieves) were studied. After SE pretreatment, the morphological structure, color attributes, and composition of phenolic compounds were altered significantly (p < .05). The composition and content of phenolic compounds were strongly correlated with particle sizes. The higher extraction yield of phenolic compounds was reached in the intermediate sieve fraction (ca. 250-µm sieves). During in vitro digestion, the changes in phenolic compounds were significant due to the transition from an acidic to the alkaline environment (p < .05). Based on the multivariate statistical analysis, apigenin-7-O-glucoside, luteolin-7-O-glucoside, and linarin, were viewed as the characteristic compounds among various samples. The results highlighted that the phytochemical properties mainly including the composition of phenolic compounds, and in vitro digestion properties of HBJ powder with intermediate sieve fraction could be improved after SE pretreatment.

In Situ Quality Assessment of Dried Sea Cucumber (Stichopus japonicus) Oxidation Characteristics during Storage by iKnife Rapid Evaporative Ionization Mass Spectrometry.

Sea cucumber (Stichopus japonicus) is one of the most luxurious and nutritious seafoods in Asia. It is always processed into dried products to prevent autolysis, but its quality is easily destructed during storage. Herein, an extremely simplified workflow was established for real-time and in situ quality assessment of dried sea cucumbers (DSCs) during storage based on the lipid oxidation characteristics using an intelligent surgical knife (iKnife) coupled with rapid evaporative ionization mass spectrometry (REIMS). The lipidomic phenotypes of DSCs at different storage times were acquired successfully, which were then processed by multivariate statistical analysis. The results showed that the discrepancy in the characteristic ions in different DSCs was significant (p < 0.05) with high R2(Y) and Q2 values (0.975 and 0.986, respectively). The receiver operating characteristic curve revealed that the ions of m/z 739.5, m/z 831.5, m/z 847.6, and m/z 859.6 were the most specific and characteristic candidate biomarkers for quality assessment of DSCs during accelerated storage. Finally, this method was validated to be qualified in precision (RSDintraday ≤ 9.65% and RSDinterday ≤ 9.36%). In conclusion, the results showed that the well-established iKnife-REIMS method was high-throughput, rapid, and reliable in the real-time quality assessment of DSCs.