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OBJECTIVE To investigate the potential therapeutic role of porous SiO2 -coated ultrasmall selenium particles nanospheres (Se@SiO2 nanospheres) pretreatment in acute pancreatitis (AP) and to investigate the related mechanism. METHODS C57BL/6 mice were randomized to the normal control (CON) group, the AP (induced by cerulein injection) (CAE) group, and AP pretreated with Se@SiO2 nanocomposites at 1 and 2 mg/kg (CAE + 1 or 2 mg/kg Se@SiO2 ) groups, respectively. Serum levels of amylase and lipase, inflammatory cytokines (interleukin [IL]-6, IL-1β and tumor necrosis factor [TNF]-α), alanine aminotransferase (ALT), aspartate aminotransferase (AST), blood urea nitrogen (BUN), and creatinine (Cr) were measured, and histopathology was performed to examine the tissue samples of the pancreas, lungs, kidneys and liver. Immunofluorescence assay of reactive oxygen species (ROS), myeloperoxidase (MPO) and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling were conducted, and levels of MPO, malondialdehyde, superoxide dismutase and glutathione were evaluated. Finally, Western blot analysis was used to evaluate protein expressions of Nrf2, HO-1, NQO1, TLR4, MyD88 and p-p65 in pancreatic tissue. RESULTS Se@SiO2 nanospheres alleviated pathological damage to the pancreas, and reduced pancreatic enzymes and inflammatory cytokines. Injury to other organs such as the liver, lungs and kidneys was also alleviated, as indicated by decreased ALT, AST, BUN, and Cr levels as well as improved histopathology. Moreover, Se@SiO2 nanospheres reduced oxidative stress, and ultimately inhibited TLR4/ MyD88/p-p65 pathway and increased the protein expressions of NQO1, Nrf2, and HO-1. CONCLUSION Se@SiO2 nanospheres may alleviate AP by relieving oxidative stress and targeting the TLR4/Myd88/p-p65 and NQO1/Nrf2/HO-1 pathways.

The mixing properties of Gemini surfactants are significantly important to the large-scale application of these surfactants. In this study, we studied the mixing properties of multiple quaternary ammonium salts (MQAS) with cationic surfactant DTAB, anionic surfactant SDS, nonionic surfactant Triton X-100 and anionic biosurfactant rhamnolipid, respectively. Moreover, the phase behavior and aggregation properties of MQAS/SDS mixtures in water were examined by ocular observations and DLS. For equilibrium surface properties, unlike MQAS/DTAB and MQAS/TX-100 mixtures, the equimolar cationic/anionic mixtures (MQAS/SDS and MQAS/RL mixtures) have a lower critical micelle concentration than either pure component. This is always attributed to the formation of cationic surfactant complexes through the electrostatic attraction of hydrophilic groups. Results of dynamic surface properties show that MQAS/TX-100 mixtures exhibit the best dynamic surface activity among these surfactant mixtures, resulting from the good dynamic surface activity of TX-100 and the weak interaction between MQAS and TX-100. Considering the large size of cationic/anionic surfactant complexes, the MQAS/SDS and MQAS/RL mixtures have a smaller R1/2 value, but the γm values of equimolar cationic/anionic mixtures are lower than either pure components. This suggests that the formation of cationic/anionic surfactant complexes reduces the electrostatic adsorption barrier. In the anionic-rich side, the MQAS/SDS mixtures are prone to form vesicles, while the addition of a small amount of MQAS will induce the micelle-to-vesicle transition, which can be regulated by the composition of mixtures. Meanwhile, the increase of temperature induces the transition of precipitate to vesicles. But the micelle-to-vesicle or vesicle-to-micelle transitions induced by the increase of temperature have not been observed at the studied temperature range.

To investigate the potential therapeutic role of porous SiOC57BL/6 mice were randomized to the normal control (CON) group, the AP (induced by cerulein injection) (CAE) group, and AP pretreated with Se@SiOSe@SiOSe@SiO

The interaction mechanism of multiple quaternary ammonium salts (MQAS) with bovine serum albumin (BSA) was examined by the fluorescence quenching method and circular dichroism (CD) spectra. Moreover, the effects of MQAS on the dynamic properties of BSA adsorption layers at different pH values were investigated using dilational interfacial rheology. Results show that the quenching constants increase with an increase in pH values and decrease with an increase in the experiment temperature at pH 5.3. The quenching mechanism is static quenching, and the electrostatic force dominates the interaction between MQAS and BSA at pH 5.3. Due to three positive head groups, MQAS can significantly affect the dynamic interfacial activity of BSA molecules at a relatively low concentration. At pH 4.3, the electrostatic repulsion is unfavorable for the formation of MQAS/BSA complexes. Consequently, MQAS molecules will replace BSA molecules from the interface by competitive adsorption. At the pH value above the isoelectric point of BSA, the electrostatic attraction is better for the formation of MQAS/BSA complexes, which exhibit a rapid adsorption rate and an enhanced interfacial activity. Moreover, the kinetic dependencies of interfacial dilational elasticity for the MQAS/BSA mixtures become nonmonotonous. The appearance of the maximum interfacial elasticity values can be attributed to the formation of tails and loops, which suggests that the addition of MQAS destroys the secondary and tertiary structure of protein in the bulk phase. In addition, the effects of MQAS on the secondary structure of protein were demonstrated by CD spectra.