A smart cauliflower-like carrier for astaxanthin delivery to relieve colon inflammation.

As a fat-soluble carotenoid, astaxanthin has excellent antioxidant and anti-inflammation biological activities, but its poor biocompatibility and low stability limit application of astaxanthin in the food industry. In this study, cauliflower-like carriers (CCs) were constructed based on caseinate, chitosan-triphenylphosphonium (TPP) and sodium alginate through an electrostatic self-assembly method to improve the biocompatibility, stability and targeting transport properties of astaxanthin. The smart CCs showed pH-response release and mitochondrial targeted characteristics. In vitro studies demonstrated that the CCs could improve the internalization of astaxanthin, and significantly inhibited the excessive production of reactive oxygen species and the depolarization of mitochondrial membrane potential caused by oxidative stress. In vivo studies revealed that the astaxanthin-loaded CCs could effectively relieve the colitis induced by dextran sodium sulfate and protect the integrity of the colon tissue structure. The astaxanthin-loaded CCs could significantly inhibit the expression of inflammation factors such as interleukin-1ß, interleukin-6, tumor necrosis factor alpha, cyclooxygenase-2, myeloperoxidase, inducible nitric oxide synthase, and nitric oxide. Moreover, the astaxanthin-loaded CCs could maintain the expression of zonula occludens-1, increase the abundance of Firmicutes and Lactobacillaceae in the intestine. In a word, the constructed astaxanthin delivery system provided a potential application for the oral uptake hydrophobic bio-activator in intervention of ulcerative colitis.

A green initiative for oiled sand cleanup using chitosan/rhamnolipid complex dispersion with pH-stimulus response.

The released oil can affect the vulnerable shoreline environment if the oil spills happen in coastal waters. The stranded oil on shorelines is persistent, posing a long-term influence on the intertidal ecosystem after weathering. Therefore, shoreline cleanup techniques are required to remove the oil from the shoreline environment. In this study, a new shoreline cleanup initiative using chitosan/rhamnolipid (CS/RL) complex dispersion with pH-stimulus response was developed for oiled sand cleanup. The results of factorial and single-factor design revealed that the CS/RL complex dispersion maintained high removal efficiency for oiled sand with different levels of oil content in comparison to using rhamnolipid alone. However, the increase of salinity negatively affected the removal efficiency. The electrostatic screening effect of high ionic strength can hinder the formation of the CS/RL complex, and thus reduce removal efficiency. The pH-responsive characteristic of chitosan allows the easy separation of water and oil in washing effluent. The chitosan polyelectrolytes aggregated and precipitated due to the deprotonation of amino groups by adjusting the pH of the washing effluent to above 8. The microscope image demonstrated that the chitosan aggregates wrapped around the oil droplets and settled to the bottom together, thus achieving oil-water separation. Such pH-stimulus response may help achieve an easy oil-water separation after washing. These findings have important implications for developing the new strategies of oil spill response.