Various nanotechnologies have been extensively developed to prepare nanoparticles with different features for satisfying the requirements of diverse fields, but the current achievements are confined to different material systems for the limited acquisition with desirable properties. Here, we demonstrated a flexible strategy based on the broad selectivity of amines in the condensation of green tea polyphenol-EGCG (epigallocatechin gallate), formaldehyde, and amines for the rational design and preparation of versatile nanomaterials. With EGCG as the sole material system and amines (R−NH 2 ) of various functional R groups as the selectable modules, the modular assembly of polyphenolactivated condensation was straightforward and completed in one step, giving rise to different polyphenolic nanoparticles variable in surface chemistry (−amine, −aldehyde, and −carboxyl), shapes (sphere, dumbbell, walnut), internal structures (solid, hollow, and porous), stimuli responsiveness (-s-s-), and fluorescence. The flexibility of the polyphenolic condensation for versatile nanoparticles was further demonstrated by the incorporation of amino-containing anticancer or antibacterial drugs into polyphenolic nanoparticles as nanodrugs. The present study totally involved the use of 13 different amines to synthesize 18 different nanoparticles, not only convincingly specifying the enormous value of the polyphenolic condensation as platform for modular assembly of versatile nanoparticles but also revolutionizing the current strategies and methodologies for encapsulated applications of tea polyphenols.

Food-grade high internal phase Pickering emulsions (HIPPEs), as a promising delivery system for functional substances used in the field of food, medicine, and cosmetics, have attracted considerable attention nowadays. However, most of these functional substances would be easily oxidized due to the sensitivity to oxygen, light, and heat. Therefore, it is crucial to find a new strategy which could efficiently improve the antioxidation of the Pickering system. Here, a novel antioxidative HIPPE stabilized by tea polyphenol nanoparticles (TPNPs) was prepared in this study. TPNPs with a high content of active epigallocatechin gallate component were used as stabilizers, and flaxseed oil was used as the oil phase in this Pickering system. The particle size, zeta potential, morphology, and wettability tests were carried out to investigate the feasibility of TPNPs as Pickering stabilizers. The results indicated that TPNPs with appropriate size (100–400 nm), spherical morphology, and medium wettability (θow ≈ 90°) could meet the demands of Pickering stabilizers. The stability experiments showed that Pickering emulsions exhibited a remarkable physical stability (the emulsification index was up to 100%). Notably, the antioxidant assays demonstrated that the formed emulsion still performed a strong antioxidative capacity after one-month storage. Besides, the gel-like HIPPEs were also successfully obtained at low particle concentrations (1–2%) with the help of polyethylene glycol or just at the high particle concentrations (3–4%) in this study. The rheological measurements exhibited the highly stability of the gel-like emulsions. We expected that this work would be beneficial to the transportation and protection of sensitive functional compounds which could be better used in food, cosmetics, and pharmaceutical systems.

No abstract

The current strategy using the assembly of medicines and active functional molecules to develop nanomedicines often requires both molecules to have a specific matched chemical molecular structure; however, this is often difficult to predict, execute, and control in practical applications. Herein, we reported a general solvent-mediated disassembly/reassembly strategy for preparing nanomedicines based on epigallocatechin gallate (EGCG) active molecules. The polyphenol colloidal spheres (CSs) were selfassembled from molecular condensed EGCG in aqueous solution but disassembled in organic solvents and reassembled in aqueous solution. The solvent-mediated disassembly and reassembly capability of CSs gave rise to the active binding of condensed EGCG to various hydrophilic and hydrophobic guest molecules. The maximum encapsulation and drug-loading rate of reassembled CSs/DOX were 90 and 44%, respectively, and the nanomedicines could reverse drug resistance of tumor cells and exhibit enhanced therapeutic effects for breast cancer. Last but not least, 37.3 g of polyphenol CSs was massively produced at one time with a yield of 74.6%, laying a solid foundation for the practical applications of reassembled nanomedicines. The present strategy leading to a general nanomedicines platform was concise and highly efficient for both hydrophilic and hydrophobic drugs, making a breakthrough for low loading dilemma of current nanomedicines, and would open up a new direction for the preparation of nanocarriers, nanocomposites, and nanomedicines from natural polyphenols.

No abstract