pH-Switchable Pickering miniemulsion enabled by carbon quantum dots for quasi-homogenized biphasic catalytic system

Natural shellac-based microcapsules as lipase carriers for recyclable efficient Pickering interfacial biocatalysis

Enzyme is an important class of catalyst. However, the efficiency of enzyme-catalyzed reactions is constrained by the limited contact between the enzyme and its substrate. In this study, to overcome this challenge, lipase-loaded microcapsules were prepared from natural shellac and nanoparticles using the emulsion template method. These microcapsules can perform dual roles as stabilizers and enzyme carriers to construct a water-in-oil Pickering interfacial biocatalytic system. The results showed that the hydrolytic conversion of the microcapsules could reach 90% within 20 min, which was significantly higher than that of the traditional biphasic system. The catalytic activity was influenced by the oil-to-water volume ratio and the microcapsule content. The microcapsules remained highly catalytic efficiency even after storage for three months or seven cycles of reuse. These microcapsules were prepared without the use of any cross-linkers or harsh solvents. This green and efficient catalytic system has great application prospects in the food industry.

Pickering Emulsions Biocatalysis: Recent Developments and Emerging Trends

Biocatalysis within biphasic systems is gaining significant attention in the field of synthetic chemistry, primarily for its ability to solve the problem of incompatible solubilities between biocatalysts and organic compounds. By forming an emulsion from these two-phase systems, a larger surface area is created, which greatly improves the mass transfer of substrates to the biocatalysts. Among the various types of emulsions, Pickering emulsions stand out due to their excellent stability, compatibility with biological substances, and the ease with which they can be formed and separated. This makes them ideal for reusing both the emulsifiers and the biocatalysts. This review explores the latest developments in biocatalysis using Pickering emulsions. It covers the structural features, methods of creation, innovations in flow biocatalysis, and the role of interfaces in these processes. Additionally, the challenges and future directions are discussed in combining chemical and biological catalysts within Pickering emulsion frameworks to advance synthetic methodologies.

Preparation and properties of pH-sensitive cationic starch nanoparticles

Environmentally friendly and outstanding pH responsiveness cationic starch nanoparticles (CSNP) were prepared through ethanol precipitation from pH-sensitive starch, which preparation of cationic starch (CS) by grafting copolymerization with dimethylaminoethyl methacrylate (DMAEMA). In this work, CSNP showed a nanometer size and regular sphere, highly free-flowing molecular chains, and outstanding pH responsiveness which was proved by the high stability of its stabilized emulsion through 6 emulsification/ demulsification transition. The result of the SEM and particle size distribution indicated that the size of the CSNP-0 was about 800 nm, and decreased with the DMAEMA increased. Moreover, the CSNP-stabilized emulsion was stable at pH = 7 and pH = 12. However, this emulsion exhibited breakage at pH = 2. In addition, the CSNP-stabilized Pickering emulsion achieved an emulsification/demulsification switching by cycling the pH at least 6 times, during which the average droplet size gradually increased. At pH ≥ 7, the emulsions exhibit shear thinning behavior.

Properties of Ophioglossum vulgatum L. extract Pickering emulsion stabilized by carbon dots and its potential use in cosmetics

Ophioglossum vulgatum L. (O. vulgatum) is a species of fern used in traditional Chinese medicine, however, its application in cosmetics has not yet been studied. This study obtained O. vulgatum extract using 70% ethanol solution and evaporation. Fourier Transform Infrared Spectrometer (FTIR) analysis identified many active components in O. vulgatum extract, such as polyols, amino acids, and flavonoids. A Pickering emulsion of O. vulgatum extract was also prepared, stabilized by a type of carbon dot based on l-arginine (CDs-Arg). The prepared Pickering emulsion was characterized by metallographic microscope and contact angle measurement. The results demonstrated that it was a pH-responsive O/W emulsion. Facial cleanser was then created using the prepared Pickering emulsion as the main component. When squeezed onto hands, the cleanser produced many delicate foams and caused no skin irritation. The prepared Pickering emulsion facilitated the use of O. vulgatum in facial cleanser.