Anti-inflammatoryAnti-cancer Anti-atherogenic properties Bioavailability Permeability Solubility Absorption A B S T R A C T Polymethoxyflavones (PMFs) and hydroxylated polymethoxyflavones exist exclusively in citrus genus, especially in the citrus peels which have been used as herbal medicine for several diseases for thousands of years. In this review, the natural occurrence, isolation and separation of PMFs; synthetic scheme of hydroxylated PMF preparation, especially the reaction mechanism of preparation of 5-hydroxylated PMFs; biotransformation and metabolic fate of PMFs; the preliminary study on PMF bioavailability and the close relationship among solubility, permeability, absorption and oral bioavailability are summarized.The published bioactivity data on anti-inflammatory, anti-cancer and anti-atherogenic properties of PMFs have also been detailed along with a report of new findings of hydroxylated PMFs and their potent biological activities.

The carbonyl stress that leads to the formation of advanced glycation end products (AGEs) in diabetes mellitus has drawn much attention recently. Reactive alpha-dicarbonyl compounds, such as glyoxal (GO) and methylglyoxal (MGO), have been shown to be a high potential glycation agent in vitro and in vivo. In this study, epicatechins in green tea and theaflavins in black tea were found to be able to reduce the concentration of MGO in physiological phosphate buffer conditions. Modified MGO derivatization for GC/flame ionization detector (FID) method in quantification was systematically conducted. In molar ratio of 3 (MGO/polyphenol), theaflavin-3,3'-digallate (TF3) in theaflavins and (-)-epigallocatechin (EGC) in epicatechins showed the highest MGO reduction at 66.65 and 45.74%, respectively, after 1 h of incubation. In kinetic study (molar ratio of MGO/polyphenol = 1:1), rapid MGO reduction occurred within 10 min. Identities of primary adducts between (-)-epigallocatechin gallate (EGCG) and MGO were determined. Newly generated stereoisomers at the C8 position of EGCG A-ring were isolated with a chiral column, and structurally confirmed by 2-D NMR analyses.

Biological materials achieve directional reinforcement with oriented assemblies of anisotropic building blocks. One such example is the nanocomposite structure of keratinized epithelium on the toe pad of tree frogs, in which hexagonal arrays of (soft) epithelial cells are crossed by densely packed and oriented (hard) keratin nanofibrils. Here, a method is established to fabricate arrays of tree-frog-inspired composite micropatterns composed of polydimethylsiloxane (PDMS) micropillars embedded with polystyrene (PS) nanopillars. Adhesive and frictional studies of these synthetic materials reveal a benefit of the hierarchical and anisotropic design for both adhesion and friction, in particular, at high matrix–fiber interfacial strengths. The presence of PS nanopillars alters the stress distribution at the contact interface of micropillars and therefore enhances the adhesion and friction of the composite micropattern. The results suggest a design principle for bioinspired structural adhesives, especially for wet environments.

In the present work, a series of thermoplastic polyurethane (TPU)/microfibrillated cellulose (MFC) nanocomposites were successfully synthesized via in situ polymerization. TPU was covalently grafted onto the MFC by particular association with the hard segments, as evidenced by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis. The adequate dispersion and network structure of MFC in the TPU matrix and the strong interfacial interaction through covalent grafting and hydrogen bonding between MFC and TPU resulted in significantly improved mechanical properties and thermostability of the prepared nanocomposites. The tensile strength and elongation-at-break of the nanocomposite containing only 1 wt % MFC were increased by 4.5-fold and 1.8-fold compared with that of neat TPU, respectively. It was also very interesting to find that the glass transition temperature (Tg) of TPU was decreased significantly with the introduction of MFC, indicating potential for low-temperature resistance applications. Most importantly, compared with TPU nanocomposites reinforced with other nanofillers, the TPU/MFC nanocomposites prepared in this work exhibited excellent transparency and higher reinforcing efficiency.

The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10. 1002/smll.201904248. Switchable structured adhesion on rough surfaces is highly desired for a wide range of applications. Combing the advantages of gecko seta and creeper root, a switchable fibrillar adhesive composed of polyurethane (PU) as the backing layer and graphene/shape memory polymer (GSMP) as the pillar array is developed. The photothermal effect of graphene (under UV irradiation) changes GSMP micropillars into the viscoelastic state, allowing easy and intimate contact on surfaces with a wide range of roughness. By controlling the phase state of GSMP via UV irradiation during detachment, the GSMP micropillar array can be switched between the robust-adhesion state (UV off ) and low-adhesion state (UV on). The state of GSMP micropillars determines the adhesion force capacity and the stress distribution at the detaching interface, and therefore the adhesion performance. The PU-GSMP adhesive achieves large adhesion strength (278 kPa), high switching ratio (29), and fast switching (10 s) at the same time. The results suggest a design principle for bioinspired structured adhesives, especially for reversible adhesion on surfaces with a wide range of roughness. www.advancedsciencenews.com

Flexible and highly efficient energy storage units act as one of the key components in portable electronics. In this work, by planar-integrated assembly of hierarchical ZnCo₂O₄ nanowire arrays/carbon fibers electrodes, a new class of flexible all-solid-state planar-integrated fiber supercapacitors are designed and produced via a low-cost and facile method. The as-fabricated flexible devices exhibit high-efficiency, enhanced capacity, long cycle life, and excellent electrical stability. An enhanced distributed-capacitance effect is experimentally observed for the device. This strategy enables highly flexible new structured supercapacitors with maximum functionality and minimized size, thus making it possible to be readily applied in flexible/portable photoelectronic devices.

It has long been demonstrated the gecko‐inspired micropillar array with T‐shape tips possesses the best adhesion performance of a given material. The further enhancement of the adhesion performances of T‐shape micropillars can offer redundant adhesion to compensate for the inevitable improper contacts. Here, the array of T‐shape polydimethylsiloxane (PDMS) micropillars is incorporated with gradient dispersed calcium carbonate nanoparticles in the micropillar stalk, termed as T‐shape gradient micropillars (TG), possessing the modulus gradient with stiff tip and soft root. The gradient modulus in TG facilitates the contact formation and regulates the stress at the detaching interface, resulting in a 4.6 times adhesion and 2.4 times friction as compared with the pure PDMS T‐shape micropillar arrays. The study here provides a new design strategy for the super‐strong structured dry adhesives.

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